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Multimessenger astronomy is an emerging field which aims to study astronomical objects using different ‘messengers’ or sources, like electromagnetic radiation (light), neutrinos and gravitational waves. This field gained enormous recognition after the joint detection of gravitational waves and gamma ray bursts in 2017.
________________________________________________________________________________ MIT /Caltech Advanced aLigo .
Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA.
Caltech/MIT Advanced aLigo detector installation Hanford, WA, USA.
VIRGO Gravitational Wave interferometer, near Pisa, Italy.
VIRGO Gravitational Wave interferometer, near Pisa, Italy.
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Gravitational waves can be used to identify the sky direction of an event in space and alert conventional telescopes to follow-up for other sources of radiation. However, following up on prompt emissions would require a rapid and accurate localisation of such events, which will be key for joint observations in the future.
The conventional method to accurately estimate the sky direction of gravitational waves is tedious—taking a few hours to days—while a faster online version needs only seconds. There is an emerging capacity from the LIGO-Virgo collaboration to detect gravitational waves from electromagnetic-bright binary coalescences, tens of seconds before their final merger, and provide alerts across the world. The goal is to coordinate prompt follow up observations with other telescopes around the globe to capture potential electromagnetic flashes within minutes from the mergers of two neutron stars, or a neutron star with a black hole—this was not possible before. The University of Western Australia (AU)‘s SPIIR team is one of the world leaders in this area of research. Determining sky directions within seconds of a merger event is crucial,as most telescopes need to know where to point in the sky. In our recently accepted paper [Physical Review D], led by three visiting students (undergraduate and Masters by research) at the OzGrav-UWA node, we applied analytical approximations to greatly reduce the computational time of the conventional localisation method while maintaining its accuracy. A similar semi-analytical approach has also been published in another recent study [Physical Review D].
The results from this work show great potential and will be integrated into the SPIIR online pipeline going forward in the next observing run. We hope that this work complements other methods from the LIGO-Virgo collaboration and that it will be part of some exciting discoveries.
The ARC Centres of Excellence for Gravitational Wave Discovery OzGrav (AU)
A new window of discovery.
A new age of gravitational wave astronomy.
One hundred years ago, Albert Einstein produced one of the greatest intellectual achievements in physics, the theory of general relativity. In general relativity, spacetime is dynamic. It can be warped into a black hole. Accelerating masses create ripples in spacetime known as gravitational waves (GWs) that carry energy away from the source. Recent advances in detector sensitivity led to the first direct detection of gravitational waves in 2015. This was a landmark achievement in human discovery and heralded the birth of the new field of gravitational wave astronomy. This was followed in 2017 by the first observations of the collision of two neutron-stars. The accompanying explosion was subsequently seen in follow-up observations by telescopes across the globe, and ushered in a new era of multi-messenger astronomy.
The mission of The ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) is to capitalise on the historic first detections of gravitational waves to understand the extreme physics of black holes and warped spacetime, and to inspire the next generation of Australian scientists and engineers through this new window on the Universe.
undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
offer Australian researchers opportunities to work on large-scale problems over long periods of time
establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.
Fig. 1: A typical amplitude spectrum produced with frequency bins that are tuned to the expected dark matter linewidth using the modified LPSD technique. The black line indicates the amplitude spectrum. The noise spectrum was estimated at each frequency bin from neighboring bins to yield the local noise median (blue) and 95% confidence level (CL, green). Peaks (red) above this confidence level were considered candidates for dark matter signals and analyzed further. Credit: Nature via phys.org .
The technologies behind one of the biggest scientific breakthroughs of the century – the detection of gravitational waves – are now being used in the long-standing search for Dark Matter.
Thought to make up roughly 85% of all matter in the Universe, dark matter has never been observed directly and remains one of the biggest unsolved mysteries in modern physics.
______________________________________________________ Dark Matter Background Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM, denied the Nobel, some 30 years later, did most of the work on Dark Matter.
In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.
Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.
Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.
With extremely sensitive detectors now at their disposal, already proven through several outstanding discoveries, scientists believe that existing gravitational wave technology has the true potential to finally discover the exotic material and even find out what it is made of.
In a study published today in Nature, a team led by scientists from Cardiff University’s Gravity Exploration Institute has taken the first step towards this goal by using the instruments, known as laser interferometers, to look for a new kind of dark matter for the very first time.
Until recently, it was widely believed that dark matter was composed of heavy elementary particles.
These were not discovered despite a multitude of efforts, and scientists are now turning to alternative theories to explain dark matter.
A recent theory says that dark matter is actually something called a scalar field, which would behave as invisible waves bouncing around galaxies, including our own Milky Way.
“We realised our instruments could be used to hunt for this new kind of dark matter, although they were initially designed for detecting gravitational waves,’’ said Professor Hartmut Grote, from Cardiff University’s Gravity Exploration Institute, who instigated the investigation.
Within a laser interferometer, two beams of light are bounced between mirrors before meeting up on a detector. From this, scientists can gauge with great accuracy how out of sync the beams of light are with each other, which is itself proxy for any disturbance the beams encounter.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) consists of two interferometers located in the US, each with two 4 km long arms arranged in the shape of an “L”, which were used to detect gravitational waves for the very first time in 2015, and many times since.
_____________________________________________________________________________________ LIGO–VIRGO–KAGRA
The UK/German GEO 600 detector in Germany, where Grote was lead scientist from 2009 to 2017, is another highly sensitive interferometer and was used to develop much of the technology needed to detect gravitational waves.
GEO600 | Max Planck Institute for Gravitational Physics (Albert Einstein Institute)(DE)
The GE0600 detector was used, for the very first time, in this study to search specifically for dark matter.
“Scalar field dark matter waves would pass right through the Earth and our instruments, but as they do so, would cause objects such as mirrors to vibrate ever so slightly,’’ said lead investigator Sander Vermeulen, also from Cardiff University’s Gravity Exploration Institute.
“Vibrations of mirrors would disturb the beams of light in instruments like GEO600 or the LIGO detectors in a particular way characteristic of dark matter, which is something we should be able to detect, depending on the exact properties of that dark matter.”
Even though dark matter has never been directly detected, scientists suspect it exists due to its gravitational effect on objects across the Universe. For example, a large amount of unseen matter may explain why galaxies rotate as they do, and how they could have formed in the first place.
Though the team were unsuccessful in making any sort of detection in this new study, they say they are making important first strides in terms of introducing this technology to dark matter searches and have already made progress in terms of narrowing down certain parameters for future studies.
“I was surprised by how sensitive an instrument can be for hunting dark matter when it was built for an entirely different purpose originally,” continued Professor Grote.
“We have definitively ruled out some theories that say dark matter has certain properties, so future searches now have a better idea of what to look for,” said Vermeulen.
“We believe these new techniques have the true potential to discover dark matter at some point in the future.”
Cardiff Unversity [Prifysgol Caerdydd] (WLS) is a public research university in Cardiff, Wales. Founded in 1883 as the University College of South Wales and Monmouthshire (University College Cardiff from 1972), it became a founding college of the University of Wales in 1893. It merged with the University of Wales Institute of Science and Technology (UWIST) in 1988 to form the University of Wales College, Cardiff (University of Wales, Cardiff from 1996). In 1997 it received its own degree-awarding powers, but held them in abeyance. The college adopted the public name Cardiff University in 1999; in 2005 this became its legal name, when it became an independent university and began awarding its own degrees.
Cardiff University is the third oldest university in Wales and contains three colleges: Arts, Humanities and Social Sciences; Biomedical and Life Sciences; and Physical Sciences and Engineering. It is the only Welsh member of the Russell Group of research-intensive British universities. In 2018–2019, Cardiff had a turnover of £537.1 million, including £116.0 million in research grants and contracts. It has an undergraduate enrolment of 23,960 and a total enrolment of 33,190 (according to HESA data for 2018/19) making it one of the ten largest UK universities. The Cardiff University Students’ Union works to promote student interests in the university and further afield.
Discussions on the founding of a university college in South Wales began in 1879, when a group of Welsh and English MPs urged the government to consider the poor provision of higher and intermediate education in Wales and “the best means of assisting any local effort which may be made for supplying such deficiency.”
In October 1881, William Gladstone’s government appointed a departmental committee to conduct “an enquiry into the nature and extent of intermediate and higher education in Wales”, chaired by Lord Aberdare and consisting of Viscount Emlyn, Reverend Prebendary H. G. Robinson, Henry Richard, John Rhys and Lewis Morris. The Aberdare Report, as it came to be known, took evidence from a wide range of sources and over 250 witnesses and recommended a college each for North Wales and South Wales, the latter to be located in Glamorgan and the former to be the established University College of Wales in Aberystwyth (now Aberystwyth University). The committee cited the unique Welsh national identity and noted that many students in Wales could not afford to travel to University in England or Scotland. It advocated a national degree-awarding university for Wales, composed of regional colleges, which should be non-sectarian in nature and exclude the teaching of theology.
After the recommendation was published, Cardiff Corporation sought to secure the location of the college in Cardiff, and on 12 December 1881 formed a University College Committee to aid the matter. There was competition to be the site between Swansea and Cardiff. On 12 March 1883, after arbitration, a decision was made in Cardiff’s favour. This was strengthened by the need to consider the interests of Monmouthshire, at that time not legally incorporated into Wales, and the greater sum received by Cardiff in support of the college, through a public appeal that raised £37,000 and a number of private donations, notably from the Lord Bute and Lord Windsor. In April Lord Aberdare was appointed as the College’s first president. The possible locations considered included Cardiff Arms Park, Cathedral Road, and Moria Terrace, Roath, before the site of the Old Royal Infirmary buildings on Newport Road was chosen.
The University College of South Wales and Monmouthshire opened on 24 October 1883 with courses in Biology, Chemistry, English, French, German, Greek, History, Latin, Mathematics and Astronomy, Music, Welsh, Logic and Philosophy, and Physics. It was incorporated by Royal Charter the following year, this being the first in Wales to allow the enrollment of women, and specifically forbidding religious tests for entry. John Viriamu Jones was appointed as the University’s first Principal at the age of 27. As Cardiff was not an independent university and could not award its own degrees, it prepared its students for examinations of the University of London or for further study at Oxford or Cambridge.
In 1888 the University College at Cardiff and that of North Wales (now Bangor University) proposed to the University College Wales at Aberystwyth joint action to gain a university charter for Wales, modelled on that of Victoria University, a confederation of new universities in Northern England. Such a charter was granted to the new University of Wales in 1893, allowing the colleges to award degrees as members. The Chancellor was set ex officio as the Prince of Wales, and the position of operational head would rotate among heads of the colleges.
In 1885, Aberdare Hall opened as the first hall of residence, allowing women access to the university. This moved to its current site in 1895, but remains a single-sex hall. In 1904 came the appointment of the first female associate professor in the UK, Millicent Mackenzie, who in 1910 became the first female full professor at a fully chartered UK university.
In 1901 Principal Jones persuaded Cardiff Corporation to give the college a five-acre site in Cathays Park (instead of selling it as they would have done otherwise). Soon after, in 1905, work on a new building commenced under the architect W. D. Caröe. Money ran short for the project, however. Although the side-wings were completed in the 1960s, the planned Great Hall has never been built. Caroe sought to combine the charm and elegance of his former (Trinity College, Cambridge) with the picturesque balance of many Oxford colleges. On 14 October 1909 the “New College” building in Cathays Park (now Main Building) was opened in a ceremony involving a procession from the “Old College” in Newport Road.
In 1931, the School of Medicine, founded as part of the college in 1893 along with the Departments of Anatomy, Physiology, Pathology, Pharmacology, was split off to form the Welsh National School of Medicine, which was renamed in 1984 the University of Wales College of Medicine.
In 1972, the institution was renamed University College Cardiff.
Groundbreaking discoveries about gravitational waves, black holes, cosmic rays, neutrinos and other areas of cutting-edge astronomy may soon become more frequent due to the convergence of two major communities of astronomers in a fresh project.
Previously, Europe had two major collaborative networks for ground-based astronomy running over the past couple of decades, known as OPTICON and RadioNet. These focused on observing astronomical phenomena in separate wavelength ranges of the electromagnetic spectrum – the former at optical wavelengths, in a portion of the spectrum that includes visible light; and the latter at longer, radio wavelengths.
Now, these two domains of astronomy are uniting in a project called the OPTICON RadioNet Pilot (ORP)(EU), a consortium of astronomers from 37 institutions and 15 European countries, plus Australia and South Africa.
Referring to itself as Europe’s largest astronomy network, the initiative was set up in light of the increasing need for astronomers to have a range of skills in different domains and use complementary techniques to understand phenomena. It also brings together around 20 telescopes and telescope arrays owned by members of the consortium, with the aim of harmonising methods and tools between the two domains, and opening up physical and virtual access to facilities.
He explained that the more you can observe about phenomena at different wavelengths, the more of a picture you can build. ‘Multi-wavelength astronomy is about observing across the whole spectral domain to have as much information as possible,’ he said. ‘The light we receive in optical and radio wavelengths comes from different physical processes; so the more we observe in terms of wavelength coverage, the more we learn about the physical processes.’
Dr Cuby said the aim is to facilitate and speed up the process of getting telescope time for projects that require different facilities – which can be a long-winded process – making it easier for people to do more ambitious projects that previously required vast management efforts.
The telescope facilities include the likes of LOFAR, a trans-European low-frequency radio telescope network based in the Netherlands, and EVN, a network of radio telescopes located mainly in Europe and Asia, with additional antennas in South Africa and Puerto Rico.
The telescope facilities include the likes of LOFAR, a trans-European low-frequency radio telescope network based in the Netherlands, and EVN, a network of radio telescopes located mainly in Europe and Asia, with additional antennas in South Africa and Puerto Rico.
Dr Cuby elaborated on how the need is growing to foster harmonisation between domains in the current age of so-called multi-messenger astronomy. This involves the observation of various “messenger” particles – such as gravitational waves, neutrinos and cosmic rays – that can reveal different information about the same sources, potentially giving unprecedented insight into the universe and its origins.
Harmonisation is also key for time-domain astronomy, which explores how astronomical events vary over time. Events now being explored are frequently transient, with many, like fast radio bursts, lasting mere milliseconds. Capturing multiple aspects of them thus requires rapid deployment of telescopes and facilities, which can again be aided by collaboration. ‘This time-domain astronomy is going to explode in the coming years,’ said Dr Cuby. ‘This is really the golden age of astronomy.’
Professor Gerry Gilmore, a cosmologist at The University of Cambridge (UK) who is involved in ORP as scientific coordinator for OPTICON, elaborated further. “That’s the sort of science we now do, where you discover something that’s usually highly variable and very often it’s transient,” he said. “It’s all over very quickly and you don’t get another chance. You want then to be able to bring the whole array of potential capabilities into looking at that particular place in the sky now.”
Previously, said Prof. Gilmore, capturing a transient event relied on a huge amount of luck in looking in the right place at the right time, but ORP provides a chance to “plan to be lucky” through more targeted efforts between different researchers and opens up the “discovery space” in astronomy.
“As soon as the technology became available to start looking for shorter and shorter timescale events, hey presto, we discovered they’re all there – the universe is full of stuff. And it’s the most extreme things that happen fastest.”
Gravitational waves
Much of this multi-messenger and time-domain astronomy is in its infancy, but is being opened up by advances in technologies and new deployments of cutting-edge observatories around the world.
One emerging area that ORP hopes will be spurred by collaboration is that of gravitational waves. First detected in 2015, these are ripples in space-time formed by some of the universe’s most cataclysmic events, such as pairs of black holes colliding.
This November, an international team of astronomers announced the detection of a record number of gravitational waves, adding 35 new observations over the course of roughly six months to bring the total to 90 so far.
The findings, they believe, will help further our understanding of the evolution of the universe, and topics such as the life and death of stars.
With the related study listing more than 1,600 authors from all corners of the world, and harnessing around 100 ground- and space-based instruments – including visible, infrared and radio telescopes, neutrino and gamma-ray observatories, and X-ray instruments – this reflects the hugely extensive collaboration taking place in modern astronomy.
One of the authors, Dr Sarp Akcay, a theoretical physicist at The University College Dublin (IE) who is not involved in ORP, said the ORP initiative looks promising for inspiring more rapid discoveries.
“This type of large-scale collaboration will be extremely helpful for gravitational-wave astronomy, and even more so for so-called multi-messenger astronomy,” he said. “With more telescopes joining a global network, follow-up observations can be made quicker in the future, adding to our knowledge of these events.”
Prof. Gilmore said, meanwhile, that although the main focus of ORP is on inspiring collaboration rather than carrying out specific investigations itself, a test case for the project is combining the search for black holes in the optical and radio wavelengths to find out more about their nature, exactly how common these objects are, and whether theories about them are correct.
And with the Milky Way alone thought to harbour millions of black holes, which are often formed by the death of massive stars, there’s a vast amount to find out. “There’s a handful of them that have been observed in very special circumstances,” said Prof. Gilmore. “So we’ve seen the tip of the iceberg, but we predict that there are huge numbers of them.”
=== Long-term view
Though it’s early days for ORP, which launched this March, and the exact way it develops is yet to be seen, Dr Cuby and his team hope that the pilot can later transition into a sustainable long-term project beyond its current scheduled duration until early 2025. The aim is also to enable open access to those around the world, broadening the scope for involvement of previously under-represented researchers and countries.
Prof. Gilmore said, meanwhile, that the separate communities have been increasingly converging in recent years, while the OPTICON and RadioNet projects have already established strong collaborative networks in their individual domains over many years. “The community has been changing steadily over the last few decades,” he said. “People have been forming teams and using a range of facilities for a given scientific topic. Multi-wavelength astronomy is the reality of the way we actually do it these days.”
With the ORP project, he said: “Now, it should be possible for a group of young, enthusiastic scientists just to choose their leader, she writes the proposal, and ping – off the team goes”.
Professor Anton Zensus, scientific coordinator for RadioNet in the ORP project, believes the initiative is a “crucial step” in furthering the field of astronomy that will allow a much richer picture of the universe.
“Multifrequency use allows us to better understand the secrets of the universe,” he said. “ORP will allow a fast reaction to unexpected and transient astronomical phenomena in the sky, such as gamma ray bursts. We aim on getting a full image illuminating all aspects of phenomena.”
Dr Zensus added that bringing the radio and optical communities together to harmonise astronomy is a “crucial step to make it attractive for users from all astronomical communities” and help open up this area of science to non-specialist users too. “A multi-messenger approach will deepen our understanding of astronomy phenomena, and at the same time create new questions and approaches,” he said.
[This writer is forced to ask: Will Europe eclipse the U.S.A. in especially as they did in High Energy Physics? When the U.S. Congress foolishly cancelled the Superconducting Supercollider [SSC] in Texas, the U.S allowed for the hegemony in High Energy Physics to move the the Large Hadron Collider [LHC] at CERN on the Swiss French border The LHC powered up to 14 TeV. The LHC found the Higgs Boson after Fermilab’s Tevatron could not develop the energy in TeV to do the job. The Tevetron never actually powered up to even 2 TeV. But the SSC was much larger and would have quickly developed 20 TeV in each direction.
Now the NSF seems to be abandoning Radio Astronomy, having defunded the Arecibo Radio Telescope in Puerto Rico and reducing the funding for he Green Bank Radio Telescope in West Virginia, while the European Union has committed €20 billion to Radio Astronomy.
A black hole collision should forever scar space-time. Credit: Alfred Pasieka / Science Source.
The first detection of gravitational waves in 2016 provided decisive confirmation of Einstein’s general theory of relativity. But another astounding prediction remains unconfirmed: According to general relativity, every gravitational wave should leave an indelible imprint on the structure of space-time. It should permanently strain space, displacing the mirrors of a gravitational wave detector even after the wave has passed.
Since that first detection almost six years ago, physicists have been trying to figure out how to measure this so-called “memory effect.”
“The memory effect is absolutely a strange, strange phenomenon,” said Paul Lasky, an astrophysicist at Monash University (AU). “It’s really deep stuff.”
Their goals are broader than just glimpsing the permanent space-time scars left by a passing gravitational wave. By exploring the links between matter, energy and space-time, physicists hope to come to a better understanding of Stephen Hawking’s black hole information paradox, which has been a major focus of theoretical research for going on five decades. “There’s an intimate connection between the memory effect and the symmetry of space-time,” said Kip Thorne, a physicist at The California Institute of Technology (US) whose work on gravitational waves earned him part of the 2017 Nobel Prize in Physics. “It is connected ultimately to the loss of information in black holes, a very deep issue in the structure of space and time.”
A Scar in Space-Time
Why would a gravitational wave permanently change space-time’s structure? It comes down to general relativity’s intimate linking of space-time and energy.
First consider what happens when a gravitational wave passes by a gravitational wave detector. The Laser Interferometer Gravitational-Wave Observatory (LIGO) has two arms positioned in an L shape [see Livingstone, LA installation above]. If you imagine a circle circumscribing the arms, with the center of the circle at the arms’ intersection, a gravitational wave will periodically distort the circle, squeezing it vertically, then horizontally, alternating until the wave has passed. The difference in length between the two arms will oscillate — behavior that reveals the distortion of the circle, and the passing of the gravitational wave.
According to the memory effect, after the passing of the wave, the circle should remain permanently deformed by a tiny amount. The reason why has to do with the particularities of gravity as described by general relativity.
The objects that LIGO detects are so far away, their gravitational pull is negligibly weak. But a gravitational wave has a longer reach than the force of gravity. So, too, does the property responsible for the memory effect: the gravitational potential.
In simple Newtonian terms, a gravitational potential measures how much energy an object would gain if it fell from a certain height. Drop an anvil off a cliff, and the speed of the anvil at the bottom can be used to reconstruct the “potential” energy that falling off the cliff can impart.
But in general relativity, where space-time is stretched and squashed in different directions depending on the motions of bodies, a potential dictates more than just the potential energy at a location — it dictates the shape of space-time.
“The memory is nothing but the change in the gravitational potential,” said Thorne, “but it’s a relativistic gravitational potential.” The energy of a passing gravitational wave creates a change in the gravitational potential; that change in potential distorts space-time, even after the wave has passed.
How, exactly, will a passing wave distort space-time? The possibilities are literally infinite, and, puzzlingly, these possibilities are also equivalent to one another. In this manner, space-time is like an infinite game of Boggle. The classic Boggle game has 16 six-sided dice arranged in a four-by-four grid, with a letter on each side of each die. Each time a player shakes the grid, the dice clatter around and settle into a new arrangement of letters. Most configurations are distinguishable from one another, but all are equivalent in a larger sense. They are all at rest in the lowest-energy state that the dice could possibly be in. When a gravitational wave passes through, it shakes the cosmic Boggle board, changing space-time from one wonky configuration to another. But space-time remains in its lowest-energy state.
Super Symmetries
That characteristic — that you can change the board, but in the end things fundamentally stay the same — suggests the presence of hidden symmetries in the structure of space-time. Within the past decade, physicists have explicitly made this connection.
The story starts back in the 1960s, when four physicists wanted to better understand general relativity. They wondered what would happen in a hypothetical region infinitely far from all mass and energy in the universe, where gravity’s pull can be neglected, but gravitational radiation cannot. They started by looking at the symmetries this region obeyed.
They already knew the symmetries of the world according to special relativity, where space-time is flat and featureless. In such a smooth world, everything looks the same regardless of where you are, which direction you’re facing, and the speed at which you’re moving. These properties correspond to the translational, rotational and boost symmetries, respectively. The physicists expected that infinitely far from all the matter in the universe, in a region referred to as “asymptotically flat,” these simple symmetries would reemerge.
To their surprise, they found an infinite set of symmetries in addition to the expected ones. The new “supertranslation” symmetries indicated that individual sections of space-time could be stretched, squeezed and sheared, and the behavior in this infinitely distant region would remain the same.
In the 1980s, Abhay Ashtekar, a physicist at The Pennsylvania State University (US), discovered that the memory effect was the physical manifestation of these symmetries. In other words, a supertranslation was exactly what would cause the Boggle universe to pick a new but equivalent way to warp space-time.
His work connected these abstract symmetries in a hypothetical region of the universe to real effects. “To me that’s the exciting thing about measuring the memory effect — it’s just proving these symmetries are really physical,” said Laura Donnay, a physicist at The Vienna University of Technology (TU Wien)[Technische Universität Wien](AT). “Even very good physicists don’t quite grasp that they act in a nontrivial way and give you physical effects. And the memory effect is one of them.”
Probing a Paradox
The point of the Boggle game is to search the seemingly random arrangement of letters on the grid to find words. Each new configuration hides new words, and hence new information.
Like Boggle, space-time has the potential to store information, which could be the key to solving the infamous black hole information paradox. Briefly, the paradox is this: Information cannot be created or destroyed. So where does the information about particles go after they fall into a black hole and are re-emitted as information-less Hawking radiation?
In 2016, Andrew Strominger, a physicist at Harvard University (US), along with Stephen Hawking [The University of Cambridge (UK)] and Malcolm Perry [The University of Cambridge (UK) and Queen Mary University of London (UK)] realized that the horizon of a black hole has the same supertranslation symmetries as those in asymptotically flat space. And by the same logic as before, there would be an accompanying memory effect. This meant the infalling particles could alter space-time near the black hole, thereby changing its information content. This offered a possible solution to the information paradox. Knowledge of the particles’ properties wasn’t lost — it was permanently encoded in the fabric of space-time.
“The fact that you can say something interesting about black hole evaporation is pretty cool,” said Sabrina Pasterski, a theoretical physicist at Princeton University (US). “The starting point of the framework has already had interesting results. And now we’re pushing the framework even further.”
Pasterski and others have launched a new research program relating statements about gravity and other areas of physics to these infinite symmetries. In chasing the connections, they’ve discovered new, exotic memory effects. Pasterski established a connection between a different set of symmetries and a spin memory effect, where space-time becomes gnarled and twisted from gravitational waves that carry angular momentum.
A Ghost in the Machine
Alas, LIGO scientists haven’t yet seen evidence of the memory effect. The change in the distance between LIGO’s mirrors from a gravitational wave is minuscule — about one-thousandth the width of a proton — and the memory effect is predicted to be 20 times smaller.
LIGO’s placement on our noisy planet worsens matters. Low-frequency seismic noise mimics the memory effect’s long-term changes in the mirror positions, so disentangling the signal from noise is tricky business.
Earth’s gravitational pull also tends to restore LIGO’s mirrors to their original position, erasing its memory. So even though the kinks in space-time are permanent, the changes in the mirror position — which enables us to measure the kinks — are not. Researchers will need to measure the displacement of the mirrors caused by the memory effect before gravity has time to pull them back down.
While detecting the memory effect caused by a single gravitational wave is infeasible with current technology, astrophysicists like Lasky and Patricia Schmidt of The University of Birmingham (UK) have thought up clever workarounds. “What you can do is effectively stack up the signal from multiple mergers,” said Lasky, “accumulating evidence in a very statistically rigorous way.”
Lasky and Schmidt have independently predicted that they’ll need over 1,000 gravitational wave events to accumulate enough statistics to confirm they’ve seen the memory effect. With ongoing improvements to LIGO, as well as contributions from the VIRGO detector in Italy and KAGRA in Japan, Lasky thinks reaching 1,000 detections is a few short years away.
“It is such a special prediction,” said Schmidt. “It’s quite exciting to see if it’s actually true.”
Correction: December 9, 2021
The original version of this article attributed the original discovery of the connection between supertranslation symmetries and the memory effect to Andrew Strominger in 2014. In fact, that connection had previously been known. The 2014 discovery by Strominger was between supertranslation symmetries, the memory effect and a third topic.
Formerly known as Simons Science News, Quanta Magazine (US) is an editorially independent online publication launched by the Simons Foundation to enhance public understanding of science. Why Quanta? Albert Einstein called photons “quanta of light.” Our goal is to “illuminate science.” At Quanta Magazine, scientific accuracy is every bit as important as telling a good story. All of our articles are meticulously researched, reported, edited, copy-edited and fact-checked.
Figure showing sections through marginal surfaces in a ‘snapshot’ of the researchers’ simulation. The apparent horizons are the three dark lines (the newly formed one is outside and contains the two original ones), while unstable marginal surfaces are lighter colored. Some of the unstable surfaces evolve to merge and annihilate with the two original (inner) apparent horizons. Credit: Pook-Kolb, Hennigar & Booth.
Binary black hole mergers are fascinating cosmological events, which have been theorized to be the among the strongest sources of gravitational waves in the universe. While astrophysicists have carried out extensive research focusing on these events, many questions remain unanswered.
Apparent horizons are boundaries delineating the edge of a black hole. In their previous works, two of the researchers involved in the recent study had been trying to develop new ways to identify apparent horizons in spacetimes simple enough that their metrics could be written down on paper. Using the methods they developed, they were able to identify several new horizon-like surfaces that had been overlooked by previous works.
“Part of the original inspiration for that study was understanding self-intersecting apparent horizons that had recently been identified during black hole mergers by Daniel and his collaborators,” Daniel Pook-Kolb, Robie A. Hennigar and Ivan Booth, the researchers who carried out the study, told Phys.org, via email. “Then, Ivan was asked to be an examiner for Daniel’s Ph.D. thesis and, while writing his report, realized that the simple methods could also be applied in Daniel’s much more complicated numerically generated merger spacetimes. After the thesis was published, we started collaborating.”
Initially, Pook-Kolb analyzed data from the full numerical simulations he produced as part of his thesis. Almost immediately, he identified a series of new structures that matched the team’s theoretical predictions.
One of the primary objectives of the new study was to gain a better understanding of how two black holes can merge and become one. As the researchers continued their analyses, they became more confident that they would be able to answer this unanswered question.
“For many years, it has been known how the event horizon looks during a merger; that’s the famous pair of pants diagram, but that does not tell us much about the dynamics, especially how the spacetime evolves inside the black holes,” Pook-Kolb, Hennigar and Booth explained. “To get more insight, we look instead at apparent horizons, which are ubiquitous in the numerical relativity community.”
Approximately 50 years ago, Stephen Hawking and George Ellis speculated briefly about what happens to the apparent horizons of binary black holes when they merge, in their book The Large Scale Structure of Space-Time. Since then, however, researchers have been unable to paint a full and consistent picture of this phenomenon.
“For a long time, this has been a fairly academic question, as black holes were elusive objects that had never been directly observed individually, let alone witnessing two of them merge,” Pook-Kolb, Hennigar and Booth said. “This has changed dramatically since the first gravitational wave signatures of mergers were detected in 2015.
Merger observations are now almost routine. We therefore think that gaining an understanding of all their aspects is interesting in itself.”
In their paper, Pook-Kolb, Hennigar and Booth specifically examined black hole configurations with a certain symmetry, where the whole system remains unchanged after rotations occur around one axis. The method they used to carry out their analysis has three key components.
Firstly, the researchers employed a highly accurate technique for simulating spacetimes, including spacetimes inside a black hole. Secondly, they used a numerical method that allowed them to resolve the horizons, even in instances when they become very distorted.
“The third ‘ingredient’ of our method is a conceptually simple way to find all the possible horizons: The equations for finding apparent horizons are rewritten from complicated equations for surfaces to relatively simple ones for curves,” Pook-Kolb, Hennigar and Booth said. “Once one finds one of these curves, it can be rotated to obtain the full surface. Then the search for horizons becomes a one-dimensional search, which is easy to tackle with today’s computers. To the best of our knowledge, no one fully worked out the mathematics for that before, yet it is what finally enabled us to uncover the structure in the interior of the newly formed black hole.”
Over the past few decades, astrophysicists were able to paint a clear picture of what happens in the exterior spacetime of black holes during binary black hole mergers. In addition, the gravitational waves that were predicted to be associated with these events are now consistently detected.
What happens in the interior spacetime, however, so far remained unclear. The recent work by Pook-Kolb, Hennigar, and Booth sheds some light on what could happen inside binary black holes when they merge.
“The most important result of our study is that it unveiled the fate of the original two horizons,” Pook-Kolb, Hennigar and Booth said. “They both eventually vanish, but they don’t just disappear. Instead, they smoothly annihilate with other horizon-like structures. One might go as far as saying ‘they turn around in time,” and in doing so, they become what we call unstable.”
A further achievement of this recent study is that it introduces a method to easily differentiate between generic marginal surfaces, also known as MOTSs, and MOTSs that can be regarded as physically meaningful black hole boundaries (i.e., horizons). In the future, this method could also be used by other research teams to study horizons in black holes.
“By computing a MOTS’s stability properties, we can immediately tell if it belongs to a physically behaving horizon or if it is just an unstable marginal surface,” Pook-Kolb, Hennigar and Booth explained. “This criterion establishes something very important to us: Despite the sheer number of marginal surfaces we found, we find a very clear and simple structure when we include the stability properties.”
In their recent study, Pook-Kolb, Hennigar and Booth report valuable new insight about what could happen to apparent horizons when two black holes merge into one. So far, their analyses considered non-spinning binary black holes, but they plan to eventually conduct further studies focusing on rotating black holes.
“Obviously, there are still many questions to address,” Pook-Kolb, Hennigar and Booth said. “Probably the most important one will be to extend our study to fully generic mergers of rotating black holes. While we do think that very similar structures should exist, we have been surprised often enough to remain extremely curious.”
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A multidisciplinary team including an LLNL mathematician has discovered a machine learning-based technique capable of automatically deriving a mathematical model for the motion of binary black holes from raw gravitational wave data. Gravitational waves are produced by cataclysmic events such as the merger of two black holes, which ripple outward as the black holes spiral toward each other and can be detected by installations such as the Laser Interferometer Gravitational-wave Observatory (LIGO). Image credit: T. Pyle/LIGO.
The announcement that the Laser Interferometer Gravitational-wave Observatory (LIGO) had detected gravitational waves during the merger of two black holes sent ripples throughout the scientific community in 2016. The earthshaking news not only confirmed one of Albert Einstein’s key predictions in his general theory of relativity, but also opened a door to a better understanding of the motion of black holes and other spacetime-warping phenomena.
Cataclysmic events such as the collision of black holes or neutron stars produce the largest gravitational waves. Binary black holes orbit around each other for billions of years before eventually colliding to form a single massive black hole. During the final moments as they merge, their mass is converted to a gigantic burst of energy — per Einstein’s equation e=mc2 — which can then be detected in the form of gravitational waves.
To understand the motion of binary black holes, researchers have traditionally simplified Einstein’s field equations and solved them to calculate the emitted gravitational waves. The approach is complex and requires expensive, time-consuming simulations on supercomputers or approximation techniques that can lead to errors or break down when applied to more complicated black hole systems.
Along with collaborators at The University of Massachusetts (US), Dartmouth College (US) and The University of Mississippi (US), a Lawrence Livermore National Laboratory (LLNL) mathematician has discovered an inverse approach to the problem, a machine learning-based technique capable of automatically deriving a mathematical model for the motion of binary black holes from raw gravitational wave data, requiring only the computing power of a laptop. The work appears online in the journal Physical Review Research.
Working backward using gravitational wave data from numerical relativity simulations, the team designed an algorithm that could learn the differential equations describing the dynamics of merging black holes for a range of cases. The waveform inversion strategy can quickly output a simple equation with the same accuracy as equations that have taken humans years to develop or models that take weeks to run on supercomputers.
“We have all this data that relates to more complicated black hole systems, and we don’t have complete models to describe the full range of these systems, even after decades of work,” said lead author Brendan Keith, a postdoctoral researcher in LLNL’s Center for Applied Scientific Computing. “Machine learning will tell us what the equations are automatically. It will take in your data, and it will output an equation in a few minutes to an hour, and that equation might be as accurate as something a person had been working on for 10-20 years.”
Keith and the other two members of the multidisciplinary team met at a computational relativity workshop at the Institute for Computational and Experimental Research in Mathematics at Brown University (US). They wanted to test ideas from recent papers describing a similar type of machine learning problem — one that derived equations based on trajectories of a dynamical system — on lower-dimensional data, like that of gravitational waves.
Keith, a computational scientist in addition to being a mathematician, wrote the inverse problem and the computer code, while his academic partners helped him obtain the data, and added the physics needed to scale from one-dimensional data to a multi-dimensional system of equations and interpret the model.
“We had some confidence that if we went from one dimension to one dimension, it would work — that’s what the earlier papers had done — but a gravitational wave is lower-dimensional data than the trajectory of a black hole,” Keith said. “It was a big, exciting moment when we found out it does work.”
The approach doesn’t require complicated general relativity theory, only the application of Kepler’s laws of planetary motion and the math needed to solve an inverse problem. Starting with just a basic Newtonian, non-relativistic model (like the moon orbiting around the Earth) and a system of differential equations parameterized by neural networks, the team discovered the algorithm could learn from the differences between the basic model and one that behaved much differently (like two orbiting black holes) to fill in the missing relativistic physics.
“This is a completely new way to approach the problem,” said co-author Scott Field, an assistant professor in mathematics and gravitational wave data scientist at The University of Massachusetts-Dartmouth (US). “The gravitational-wave modeling community has been moving towards a more data-driven approach, and our paper is the most extreme version of this, whereby we rely almost exclusively on data and sophisticated machine learning tools.”
Applying the methodology to a range of binary black hole systems, the team showed that the resulting differential equations automatically accounted for relativistic effects in black holes such as perihelion precession, radiation reaction and orbital plunge. In a side-by-side comparison with state-of-the-art orbital dynamics models that the scientific community has used for decades, the team discovered their machine learning model was equally accurate and could be applied to more complex black hole systems, including situations with higher dimension data but a limited number of observations.
“The most surprising part of the results was how well the model could extrapolate outside of the training set,” said co-author Akshay Khadse, a Ph.D. student in physics at the University of Mississippi. “This could be used for generating information in the regime where the gravitational wave detectors are not very sensitive or if we have a limited amount of gravitational wave signal.”
The researchers will need to perform more mathematical analysis and compare their predictions to more numerical relativity data before the method is ready to use with current gravitational data collected from the LIGO installations, the team said. They hope to devise a Bayesian inversion approach to quantify uncertainties and apply the technique to more complicated systems and orbital scenarios, as well as use it to better calibrate traditional gravitational-wave models.
Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration
DOE’s Lawrence Livermore National Laboratory (LLNL) (US) is an American federal research facility in Livermore, California, United States, founded by the University of California-Berkeley (US) in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System (US). In 2012, the laboratory had the synthetic chemical element livermorium named after it.
LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.
The Laboratory is located on a one-square-mile (2.6 km^2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.
LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence, director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.
The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.
Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the DOE’s Los Alamos National Laboratory(US) and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.
Historically, the DOE’s Lawrence Berkeley National Laboratory (US) and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.
The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.” The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS. The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.
On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km^2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.
A team of international scientists, including researchers from The Australian National University (ANU), and researchers from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) have unveiled the largest number of gravitational waves ever detected.
The discoveries will help solve some of the most complex mysteries of the Universe, including the building blocks of matter and the workings of space and time.
The global team’s study, published today on Physical Review X, made 35 new detections of gravitational waves caused by pairs of black holes merging or neutron stars and black holes smashing together, using the LIGO and Virgo observatories between November 2019 and March 2020.
This brings the total number of detections to 90 after three observing runs between 2015 and 2020.
The new detections are from massive cosmic events, most of them billions of light years away, which hurl ripples through space-time. They include 32 black hole pairs merging, and likely three collisions between neutron stars and black holes.
ANU is one of the key players in the international team making the observations and developing the sophisticated technology to hunt down elusive gravitational waves across the vast expanse of the Universe.
Distinguished Professor Susan Scott, from the ANU Centre for Gravitational Astrophysics, said the latest discoveries represented “a tsunami” and were a “major leap forward in our quest to unlock the secrets of the Universe’s evolution”.
“These discoveries represent a tenfold increase in the number of gravitational waves detected by LIGO and Virgo since they started observing,” Distinguished Professor Scott said.
“We’ve detected 35 events. That’s massive! In contrast, we made three detections in our first observing run, which lasted four months in 2015-16.
“This really is a new era for gravitational wave detections and the growing population of discoveries is revealing so much information about the life and death of stars throughout the Universe.
“Looking at the masses and spins of the black holes in these binary systems indicates how these systems got together in the first place.
“It also raises some really fascinating questions. For example, did the system originally form with two stars that went through their life cycles together and eventually became black holes? Or were the two black holes thrust together in a very dense dynamical environment such as at the centre of a galaxy?”
“This new technology is allowing us to observe more gravitational waves than ever before,” she said.
“We are also probing the two black hole mass gap regions and providing more tests of Einstein’s theory of general relativity.
“The other really exciting thing about the constant improvement of the sensitivity of the gravitational wave detectors is that this will then bring into play a whole new range of sources of gravitational waves, some of which will be unexpected.”
The Australian National University (AU) is a world-leading university in Australia’s capital city, Canberra. Our location points to our unique history, ties to the Australian Government and special standing as a resource for the Australian people.
Our focus on research as an asset, and an approach to education, ensures our graduates are in demand the world-over for their abilities to understand, and apply vision and creativity to addressing complex contemporary challenges.
Australian National University is regarded as one of the world’s leading research universities, and is ranked as the number one university in Australia and the Southern Hemisphere by the 2021 QS World University Rankings. It is ranked 31st in the world by the 2021 QS World University Rankings, and 59th in the world (third in Australia) by the 2021 Times Higher Education.
In the 2020 Times Higher Education Global Employability University Ranking, an annual ranking of university graduates’ employability, Australian National University was ranked 15th in the world (first in Australia). According to the 2020 QS World University by Subject, the university was also ranked among the top 10 in the world for Anthropology, Earth and Marine Sciences, Geography, Geology, Philosophy, Politics, and Sociology.
Established in 1946, Australian National University is the only university to have been created by the Parliament of Australia. It traces its origins to Canberra University College, which was established in 1929 and was integrated into Australian National University in 1960. Australian National University enrolls 10,052 undergraduate and 10,840 postgraduate students and employs 3,753 staff. The university’s endowment stood at A$1.8 billion as of 2018.
Australian National University counts six Nobel laureates and 49 Rhodes scholars among its faculty and alumni. The university has educated two prime ministers, 30 current Australian ambassadors and more than a dozen current heads of government departments of Australia. The latest releases of ANU’s scholarly publications are held through ANU Press online.
The first rendered image of a black hole, illuminated by infalling matter. In this study, researchers have proposed a model where these objects can gain mass without the addition of matter: they can cosmologically couple to the growth of the universe itself. Image Credit: Jean-Pierre Luminet, “Image of a Spherical Black Hole with Thin Accretion Disk,” Astronomy and Astrophysics 75 (1979): 228–35.
Over the past 6 years, gravitational wave observatories have been detecting black hole mergers, verifying a major prediction of Albert Einstein’s theory of gravity.
But there is a problem—many of these black holes are unexpectedly large. Now, a team of researchers from the University of Hawaiʻi at Mānoa, The University of Chicago (US), and The University of Michigan (US) have proposed a novel solution to this problem: Black holes grow along with the expansion of the universe.
Since the first observation of merging black holes by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2015, astronomers have been repeatedly surprised by their large masses.
Though they emit no light, black hole mergers are observed through their emission of gravitational waves—-ripples in the fabric of spacetime that were predicted by Einstein’s theory of general relativity.
Physicists originally expected that black holes would have masses less than about 40 times that of the Sun, because merging black holes arise from massive stars, which can’t hold themselves together if they get too big.
The LIGO and Virgo observatories, however, have found many black holes with masses greater than that of 50 suns, with some as massive as 100 suns.
Numerous formation scenarios have been proposed to produce such large black holes, but no single scenario has been able to explain the diversity of black hole mergers observed so far, and there is no agreement on which combination of formation scenarios is physically viable. This new study, published in The Astrophysical Journal Letters, is the first to show that both large and small black hole masses can result from a single pathway, wherein the black holes gain mass from the expansion of the universe itself.
Astronomers typically model black holes inside a universe that cannot expand. “It’s an assumption that simplifies Einstein’s equations because a universe that doesn’t grow has much less to keep track of,” said Kevin Croker, a professor at the UH Mānoa Department of Physics and Astronomy. “There is a trade-off though: Predictions may only be reasonable for a limited amount of time.”
Because the individual events detectable by LIGO—Virgo only last a few seconds, when analyzing any single event, this simplification is sensible. But these same mergers are potentially billions of years in the making. During the time between the formation of a pair of black holes and their eventual merger, the universe grows profoundly. If the more subtle aspects of Einstein’s theory are carefully considered, then a startling possibility emerges: The masses of black holes could grow in lockstep with the universe, a phenomenon that Croker and his team call cosmological coupling.
The most well-known example of cosmologically-coupled material is light itself, which loses energy as the universe grows. “We thought to consider the opposite effect,” said research co-author and UH Mānoa Physics and Astronomy Professor Duncan Farrah. “What would LIGO—Virgo observe if black holes were cosmologically coupled and gained energy without needing to consume other stars or gas?”
To investigate this hypothesis, the researchers simulated the birth, life, and death of millions of pairs of large stars. Any pairs where both stars died to form black holes were then linked to the size of the universe, starting at the time of their death. As the universe continued to grow, the masses of these black holes grew as they spiraled toward each other. The result was not only more massive black holes when they merged, but also many more mergers. When the researchers compared the LIGO—Virgo data to their predictions, they agreed reasonably well. “I have to say I didn’t know what to think at first,”‘ said research co-author and University of Michigan Professor Gregory Tarlé. “It was a such a simple idea, I was surprised it worked so well.”
According to the researchers, this new model is important because it doesn’t require any changes to our current understanding of stellar formation, evolution, or death. The agreement between the new model and our current data comes from simply acknowledging that realistic black holes don’t exist in a static universe. The researchers were careful to stress, however, that the mystery of LIGO—Virgo’s massive black holes is far from solved.
“Many aspects of merging black holes are not known in detail, such as the dominant formation environments and the intricate physical processes that persist throughout their lives,” said research co-author and NASA Hubble Fellow Dr. Michael Zevin. “While we used a simulated stellar population that reflects the data we currently have, there’s a lot of wiggle room. We can see that cosmological coupling is a useful idea, but we can’t yet measure the strength of this coupling.”
Research co-author and UH Mānoa Physics and Astronomy Professor Kurtis Nishimura expressed his optimism for future tests of this novel idea, “As gravitational-wave observatories continue to improve sensitivities over the next decade, the increased quantity and quality of data will enable new analysis techniques. This will be measured soon enough.”
The The University of Hawai‘I (US) includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.
The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.
UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.
The University of Hawaiʻi system, formally the University of Hawaiʻi (US) is a public college and university system that confers associate, bachelor’s, master’s, and doctoral degrees through three university campuses, seven community college campuses, an employment training center, three university centers, four education centers and various other research facilities distributed across six islands throughout the state of Hawaii in the United States. All schools of the University of Hawaiʻi system are accredited by the Western Association of Schools and Colleges. The U.H. system’s main administrative offices are located on the property of the University of Hawaiʻi at Mānoa in Honolulu CDP.
The University of Hawaiʻi-Mānoa is the flagship institution of the University of Hawaiʻi system. It was founded as a land-grant college under the terms of the Morrill Acts of 1862 and 1890. Programs include Hawaiian/Pacific Studies, Astronomy, East Asian Languages and Literature, Asian Studies, Comparative Philosophy, Marine Science, Second Language Studies, along with Botany, Engineering, Ethnomusicology, Geophysics, Law, Business, Linguistics, Mathematics, and Medicine. The second-largest institution is the University of Hawaiʻi at Hilo on the “Big Island” of Hawaiʻi, with over 3,000 students. The University of Hawaiʻi-West Oʻahu in Kapolei primarily serves students who reside in Honolulu’s western and central suburban communities. The University of Hawaiʻi Community College system comprises four community colleges island campuses on O’ahu and one each on Maui, Kauaʻi, and Hawaiʻi. The schools were created to improve accessibility of courses to more Hawaiʻi residents and provide an affordable means of easing the transition from secondary school/high school to college for many students. University of Hawaiʻi education centers are located in more remote areas of the State and its several islands, supporting rural communities via distance education.
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The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the island of Hawai’i feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.
An oncoming tsunami of data threatens to overwhelm huge data-rich research projects on such areas that range from the tiny neutrino to an exploding supernova, as well as the mysteries deep within the brain.
Left to right: Erik Katsavounidis of MIT’s Kavli Institute, Philip Harris of the Department of Physics, and Song Han of the Department of Electrical Engineering and Computer Science are part of a team from nine institutions that secured $15 million in National Science Foundation funding to set up the Accelerated AI Algorithms for Data-Driven Discovery (A3D3) Institute. Photo: Sandi Miller.
When LIGO picks up a gravitational-wave signal from a distant collision of black holes and neutron stars, a clock starts ticking for capturing the earliest possible light that may accompany them: time is of the essence in this race.
Data collected from electrical sensors monitoring brain activity are outpacing computing capacity. Information from the Large Hadron Collider (LHC)’s smashed particle beams will soon exceed 1 petabit per second.
To tackle this approaching data bottleneck in real-time, a team of researchers from nine institutions led by The University of Washington (US), including The Massachusetts Institute of Technology (US), has received $15 million in funding to establish the Accelerated AI Algorithms for Data-Driven Discovery (A3D3) Institute. From MIT, the research team includes Philip Harris, assistant professor of physics, who will serve as the deputy director of the A3D3 Institute; Song Han, assistant professor of electrical engineering and computer science, who will serve as the A3D3’s co-PI; and Erik Katsavounidis, senior research scientist with the MIT Kavli Institute for Astrophysics and Space Research.
Infused with this five-year Harnessing the Data Revolution Big Idea grant, and jointly funded by the Office of Advanced Cyberinfrastructure, A3D3 will focus on three data-rich fields: multi-messenger astrophysics, high-energy particle physics, and brain imaging neuroscience. By enriching AI algorithms with new processors, A3D3 seeks to speed up AI algorithms for solving fundamental problems in collider physics, neutrino physics, astronomy, gravitational-wave physics, computer science, and neuroscience.
“I am very excited about the new Institute’s opportunities for research in nuclear and particle physics,” says Laboratory for Nuclear Science Director Boleslaw Wyslouch. “Modern particle detectors produce an enormous amount of data, and we are looking for extraordinarily rare signatures. The application of extremely fast processors to sift through these mountains of data will make a huge difference in what we will measure and discover.”
“Before the development of HLS4ML, the fastest processing that we knew of was roughly a millisecond per AI inference, maybe a little faster,” says Harris. “We realized all the AI algorithms were designed to solve much slower problems, such as image and voice recognition. To get to nanosecond inference timescales, we recognized we could make smaller algorithms and rely on custom implementations with Field Programmable Gate Array (FPGA) processors in an approach that was largely different from what others were doing.”
A few months later, Harris presented their research at a physics faculty meeting, where Katsavounidis became intrigued. Over coffee in Building 7, they discussed combining Harris’ FPGA with Katsavounidis’s use of machine learning for finding gravitational waves. FPGAs and other new processor types, such as graphics processing units (GPUs), accelerate AI algorithms to more quickly analyze huge amounts of data.
“I had worked with the first FPGAs that were out in the market in the early ’90s and have witnessed first-hand how they revolutionized front-end electronics and data acquisition in big high-energy physics experiments I was working on back then,” recalls Katsavounidis. “The ability to have them crunch gravitational-wave data has been in the back of my mind since joining LIGO over 20 years ago.”
Two years ago they received their first grant, and the University of Washington’s Shih-Chieh Hsu joined in. The team initiated the Fast Machine Lab, published about 40 papers on the subject, built the group to about 50 researchers, and “launched a whole industry of how to explore a region of AI that has not been explored in the past,” says Harris. “We basically started this without any funding. We’ve been getting small grants for various projects over the years. A3D3 represents our first large grant to support this effort.”
“What makes A3D3 so special and suited to MIT is its exploration of a technical frontier, where AI is implemented not in high-level software, but rather in lower-level firmware, reconfiguring individual gates to address the scientific question at hand,” says Rob Simcoe, director of MIT Kavli Institute for Astrophysics and Space Research and the Francis Friedman Professor of Physics. “We are in an era where experiments generate torrents of data. The acceleration gained from tailoring reprogrammable, bespoke computers at the processor level can advance real-time analysis of these data to new levels of speed and sophistication.”
The Huge Data from the Large Hadron Collider
With data rates already exceeding 500 terabits per second, the LHC processes more data than any other scientific instrument on earth. Its future aggregate data rates will soon exceed 1 petabit per second, the biggest data rate in the world.
“Through the use of AI, A3D3 aims to perform advanced analyses, such as anomaly detection, and particle reconstruction on all collisions happening 40 million times per second,” says Harris.
The goal is to find within all of this data a way to identify the few collisions out of the 3.2 billion collisions per second that could reveal new forces, explain how Dark Matter is formed, and complete the picture of how fundamental forces interact with matter. Processing all of this information requires a customized computing system capable of interpreting the collider information within ultra-low latencies.
“The challenge of running this on all of the 100s of terabits per second in real-time is daunting and requires a complete overhaul of how we design and implement AI algorithms,” says Harris. “With large increases in the detector resolution leading to data rates that are even larger the challenge of finding the one collision, among many, will become even more daunting.”
The Brain and the Universe
Thanks to advances in techniques such as medical imaging and electrical recordings from implanted electrodes, neuroscience is also gathering larger amounts of data on how the brain’s neural networks process responses to stimuli and perform motor information. A3D3 plans to develop and implement high-throughput and low-latency AI algorithms to process, organize, and analyze massive neural datasets in real time, to probe brain function in order to enable new experiments and therapies.
With Multi-Messenger Astrophysics (MMA), A3D3 aims to quickly identify astronomical events by efficiently processing data from gravitational waves, gamma-ray bursts, and neutrinos picked up by telescopes and detectors.
“We have reached a point where detector network growth will be transformative, both in terms of event rates and in terms of astrophysical reach and ultimately, discoveries,” says Katsavounidis. “‘Fast’ and ‘efficient’ is the only way to fight the ‘faint’ and ‘fuzzy’ that is out there in the universe, and the path for getting the most out of our detectors. A3D3 on one hand is going to bring production-scale AI to gravitational-wave physics and multi-messenger astronomy; but on the other hand, we aspire to go beyond our immediate domains and become the go-to place across the country for applications of accelerated AI to data-driven disciplines.”
The mission of the MIT Kavli Institute (MKI) for Astrophysics and Space Research is to facilitate and carry out the research programs of faculty and research staff whose interests lie in the broadly defined area of astrophysics and space research. Specifically, the MKI will
Provide an intellectual home for faculty, research staff, and students engaged in space- and ground-based astrophysics
Develop and operate space- and ground-based instrumentation for astrophysics
Engage in technology development
Maintain an engineering and technical core capability for enabling and supporting innovative research
Communicate to students, educators, and the public an understanding of and an appreciation for the goals, techniques and results of MKI’s research.
The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.
The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.
To date, The Kavli Foundation has made grants to establish Kavli Institutes on the campuses of 20 major universities. In addition to the Kavli Institutes, nine Kavli professorships have been established: three at Harvard University, two at University of California, Santa Barbara, one each at University of California, Los Angeles, University of California, Irvine, Columbia University, Cornell University, and California Institute of Technology.
The Kavli Institutes:
The Kavli Foundation’s 20 institutes focus on astrophysics, nanoscience, neuroscience and theoretical physics.
Astrophysics
The Kavli Institute for Particle Astrophysics and Cosmology at Stanford University
The Kavli Institute for Cosmological Physics, University of Chicago
The Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology
The Kavli Institute for Astronomy and Astrophysics at Peking University
The Kavli Institute for Cosmology at the University of Cambridge
The Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo
Nanoscience
The Kavli Institute for Nanoscale Science at Cornell University
The Kavli Institute of Nanoscience at Delft University of Technology in the Netherlands
The Kavli Nanoscience Institute at the California Institute of Technology
The Kavli Energy NanoSciences Institute at University of California, Berkeley and the Lawrence Berkeley National Laboratory
The Kavli Institute for NanoScience Discovery at the University of Oxford
Neuroscience
The Kavli Institute for Brain Science at Columbia University
The Kavli Institute for Brain & Mind at the University of California, San Diego
The Kavli Institute for Neuroscience at Yale University
The Kavli Institute for Systems Neuroscience at the Norwegian University of Science and Technology
The Kavli Neuroscience Discovery Institute at Johns Hopkins University
The Kavli Neural Systems Institute at The Rockefeller University
The Kavli Institute for Fundamental Neuroscience at the University of California, San Francisco
Theoretical physics
Kavli Institute for Theoretical Physics at the University of California, Santa Barbara
The Kavli Institute for Theoretical Physics China at the University of Chinese Academy of Sciences
Most elements lighter than iron are forged in the cores of stars. A star’s white-hot center fuels the fusion of protons, squeezing them together to build progressively heavier elements. But beyond iron, scientists have puzzled over what could give rise to gold, platinum, and the rest of the universe’s heavy elements, whose formation requires more energy than a star can muster.
A new study by researchers at MIT and the University of New Hampshire finds that of two long-suspected sources of heavy metals, one is more of a goldmine than the other.
The study, published today in The Astrophysical Journal Letters, reports that in the last 2.5 billion years, more heavy metals were produced in binary neutron star mergers, or collisions between two neutron stars, than in mergers between a neutron star and a black hole.
The study is the first to compare the two merger types in terms of their heavy metal output, and suggests that binary neutron stars are a likely cosmic source for the gold, platinum, and other heavy metals we see today. The findings could also help scientists determine the rate at which heavy metals are produced across the universe.
“What we find exciting about our result is that to some level of confidence we can say binary neutron stars are probably more of a goldmine than neutron star-black hole mergers,” says lead author Hsin-Yu Chen, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research (US).
As stars undergo nuclear fusion, they require energy to fuse protons to form heavier elements. Stars are efficient in churning out lighter elements, from hydrogen to iron. Fusing more than the 26 protons in iron, however, becomes energetically inefficient.
“If you want to go past iron and build heavier elements like gold and platinum, you need some other way to throw protons together,” Vitale says.
Scientists have suspected supernovae might be an answer. When a massive star collapses in a supernova, the iron at its center could conceivably combine with lighter elements in the extreme fallout to generate heavier elements.
In 2017, however, a promising candidate was confirmed, in the form a binary neutron star merger, detected for the first time by LIGO and Virgo, the gravitational-wave observatories in the United States and in Italy, respectively.
The detectors picked up gravitational waves, or ripples through space-time, that originated 130 million light years from Earth, from a collision between two neutron stars — collapsed cores of massive stars, that are packed with neutrons and are among the densest objects in the universe.
The cosmic merger emitted a flash of light, which contained signatures of heavy metals.
“The magnitude of gold produced in the merger was equivalent to several times the mass of the Earth,” Chen says. “That entirely changed the picture. The math showed that binary neutron stars were a more efficient way to create heavy elements, compared to supernovae.”
Chen and her colleagues wondered: How might neutron star mergers compare to collisions between a neutron star and a black hole? This is another merger type that has been detected by LIGO and Virgo and could potentially be a heavy metal factory. Under certain conditions, scientists suspect, a black hole could disrupt a neutron star such that it would spark and spew heavy metals before the black hole completely swallowed the star.
The team set out to determine the amount of gold and other heavy metals each type of merger could typically produce. For their analysis, they focused on LIGO and Virgo’s detections to date of two binary neutron star mergers and two neutron star – black hole mergers.
The researchers first estimated the mass of each object in each merger, as well as the rotational speed of each black hole, reasoning that if a black hole is too massive or slow, it would swallow a neutron star before it had a chance to produce heavy elements. They also determined each neutron star’s resistance to being disrupted. The more resistant a star, the less likely it is to churn out heavy elements. They also estimated how often one merger occurs compared to the other, based on observations by LIGO, Virgo, and other observatories.
Finally, the team used numerical simulations developed by Foucart, to calculate the average amount of gold and other heavy metals each merger would produce, given varying combinations of the objects’ mass, rotation, degree of disruption, and rate of occurrence.
On average, the researchers found that binary neutron star mergers could generate two to 100 times more heavy metals than mergers between neutron stars and black holes. The four mergers on which they based their analysis are estimated to have occurred within the last 2.5 billion years. They conclude then, that during this period, at least, more heavy elements were produced by binary neutron star mergers than by collisions between neutron stars and black holes.
The scales could tip in favor of neutron star-black hole mergers if the black holes had high spins, and low masses. However, scientists have not yet observed these kinds of black holes in the two mergers detected to date.
Chen and her colleagues hope that, as LIGO and Virgo resume observations next year, more detections will improve the team’s estimates for the rate at which each merger produces heavy elements. These rates, in turn, may help scientists determine the age of distant galaxies, based on the abundance of their various elements.
“You can use heavy metals the same way we use carbon to date dinosaur remains,” Vitale says. “Because all these phenomena have different intrinsic rates and yields of heavy elements, that will affect how you attach a time stamp to a galaxy. So, this kind of study can improve those analyses.”
This research was funded, in part, by NASA, the National Science Foundation, and the LIGO Laboratory.
Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology (US) adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.
As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology (US) . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology (US) is a member of the Association of American Universities (AAU).
Foundation and vision
In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.
Rogers, a professor from the University of Virginia (US), wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:
“The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”
The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.
Early developments
Two days after Massachusetts Institute of Technology (US) was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst (US)). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.
Massachusetts Institute of Technology (US) was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.
The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology (US) faculty and alumni rebuffed Harvard University (US) president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.
In 1916, the Massachusetts Institute of Technology (US) administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.
Curricular reforms
In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology (US) catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities (US)in 1934.
Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at Massachusetts Institute of Technology (US) that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.
Massachusetts Institute of Technology (US)‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology (US)’s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, Massachusetts Institute of Technology (US) became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.
These activities affected Massachusetts Institute of Technology (US) profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of Massachusetts Institute of Technology (US) between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, Massachusetts Institute of Technology (US) no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.
In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and Massachusetts Institute of Technology (US)’s defense research. In this period Massachusetts Institute of Technology (US)’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. Massachusetts Institute of Technology (US) ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT (US) Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology (US) students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)
In the 1980s, there was more controversy at Massachusetts Institute of Technology (US) over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, Massachusetts Institute of Technology (US)’s research for the military has included work on robots, drones and ‘battle suits’.
Recent history
Massachusetts Institute of Technology (US) has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology (US) classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.
Massachusetts Institute of Technology (US) was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.
In 2001, inspired by the open source and open access movements, Massachusetts Institute of Technology (US) launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, Massachusetts Institute of Technology (US) announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology (US) faculty adopted an open-access policy to make its scholarship publicly accessible online.
Massachusetts Institute of Technology (US) has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology (US) community with thousands of police officers from the New England region and Canada. On November 25, 2013, Massachusetts Institute of Technology (US) announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of the Massachusetts Institute of Technology (US) community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.
In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.
It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology (US) physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also an Massachusetts Institute of Technology (US) graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.
The mission of Massachusetts Institute of Technology (US) is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.
MIT /Caltech Advanced aLigo . 
Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA. 
Caltech/MIT Advanced aLigo detector installation Hanford, WA, USA. 
VIRGO Gravitational Wave interferometer, near Pisa, Italy. 
VIRGO Gravitational Wave interferometer, near Pisa, Italy.
sciencesprings 