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  • richardmitnick 4:57 pm on April 24, 2017 Permalink | Reply
    Tags: , , Basic Research, , , Where Is Spitzer Now?   

    From Spitzer: “Where Is Spitzer Now?” 

    NASA Spitzer Telescope



    Current Observation Details
    Target Name NGC1385
    RA 3:37:28.32
    Declination -24:30: 4.60
    Program Name SPIRITS1 1
    Principal Investigator Kasliwal
    AOT iracmapp
    Start Time 2017-04-24 21:43:34 UTC
    Duration of Observation 29.39

    How To Read The Details
    Target Name
    This is the name of the object being observed by Spitzer. The name appears as it was input by the observer, and will usually appear as a unique, universally accepted catalog designation rather than a “name” in the traditional sense of the word.
    These are the coordinates in the sky where the object is located. They work much like longitude and latitude on Earth. RA is the object’s position along the equator, and Declination is its position north or south (positive numbers are the northern sky, and negative numbers are the southern sky).
    These are the coordinates in the sky where the object is located. They work much like longitude and latitude on Earth. RA is the object’s position along the equator, and Declination is its position north or south (positive numbers are the northern sky, and negative numbers are the southern sky).
    Program Name
    When astronomers are granted observing time on Spitzer, their planned observations are defined under a unique program name. Each program has specific goals and objectives, such as the various Legacy Science programs, whose objective is to create a substantial and coherent database of archived observations that can be used by subsequent Spitzer researchers.
    Principal Investigator
    This is the name of the scientist who leads the team of people who are making the observation on Spitzer.
    This is the specific observing mode that Spitzer is using for its observation. Spitzer has three different instruments (IRAC – The Infrared Array Camera, IRS – The Infrared Spectrograph, and MIPS – The Multiband Imaging Photometer for Spitzer), all of which can be used in several different ways.
    Start Time
    The time that the observation began. The times are given in UTC (also known as Greenwich Mean Time), which is 8 hours ahead of Pacific Standard Time (7 hours ahead of Pacific Daylight Time).
    Duration of Observation

    Different observations require different amounts of time to gather all the data. Some observations can be quite quick, and some can take hours.

    See the full article here .

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    The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory located on the campus of the California Institute of Technology and part of NASA’s Infrared Processing and Analysis Center.

    NASA image

    NASA JPL Icon

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  • richardmitnick 4:03 pm on April 24, 2017 Permalink | Reply
    Tags: , Astrophotography, , Basic Research, ,   

    From Liverpool: “Shooting for the stars: capturing the beauty of science through astrophotography” 

    Liverpool John Moores University

    Thor’s Helmet is a planetary nebula. Nothing to do with planets, it is actually a shell of gas being thrown off from an old star towards the end of its life cycle. Planetary nebulae are wonderfully varied in shape and colour. This image was originally obtained with the Liverpool Telescope for BBC Sky At Night.

    2-metre Liverpool Telescope at La Palma in the Canary Islands

    Castell Alun High School captured the Messier 27 through the NSO.

    National Solar Observatory at Kitt Peak in Arizona

    One of the best planetary nebulae to observe on the NSO, it almost fills the field of view, providing a spectacular image with vast detail. The image was produced by combining observations in the blue, visual and red filters using NSO’s 3-colour image tool.

    The Crab Nebula is a supernova remnant, the expanding cloud of gas and dust from a catastrophically exploding star. Chinese astronomers witnessed this explosion in 1054 and we still see the remnant cloud now. To the human eye, it would be faint pink. Scientific instruments do not necessarily ‘see’ colours the same way as our eyes and allow astronomers to bring out details that a true colour image might not reveal.

    When thinking about the types of photographs that capture the beauty of science, a stunning landscape or an animal in its natural habitat might come to mind. But when it comes to images from telescopes, we might not immediately consider these as anything more than the collection of scientific data. Beyond their significance in helping us to discover more about our universe, the images of galaxies, planets and stars are also appreciated purely for aesthetic reasons. For many amateur and professional astrophotographers capturing the shapes and colours of the universe is just as important as capturing scientific data. In fact, most astronomical images for general viewing have been modified from their original form. An astrophotographer’s goal in this case is to bring out the best of the image – to find the art within the science.

    Robert Smith, creator of the “Iridis” image which won the Robotic Scope Special Prize at the Insight Astronomy Photographer of the Year competition, sums up the concept of science as art/art as science:

    “We often hear about the idea of representing scientific data in an appealing way as an expression of art, but why not look at it the other way around; ‘art as science’? Astrophotography is not just a matter of making science look pretty, it shows us that beauty actually is science. The winners of this competition were obviously selected because they were beautiful, striking or interesting, but each and every one is also an expression of astrophysical processes and could be the basis of a science seminar in their own right. It is physics that creates that beauty. Looking at the swirling gas in a nebula or the aurorae, you are literally seeing maths and physics.”

    Robert is an astronomer at the Astrophysics Research Institute (ARI) at LJMU and captured the award-winning image from ARI’s very own Liverpool Telescope. As the world’s largest fully robotic telescope, the Liverpool Telescope is responsible for a wide range of images which, in addition to their obvious importance scientifically, are also interesting and beautiful as pieces of art in their own right.

    Astronomers were among the first to embrace photography, with the first images of the sun captured on daguerreotypes, an early photographic imaging process, in the 1840s.

    Users of the Liverpool Telescope not only include researchers at LJMU but because it is remotely operated, it is available to astronomers from around the world. Schools and colleges across the UK and Ireland also get involved in capturing astronomical images. As a part of ARI’s educational outreach programmes, the National Schools’ Observatory (NSO) makes it possible for schoolchildren to study the night sky for themselves via the Telescope. Almost 4,000 schools have already participated with students making well over 100,000 astronomical observations from the classroom. A couple examples of the photos from NSO can be found on this page, but feel free to take a look at more on the NSO website.


    How do you photograph a night sky?

    Make sure it’s a clear night and find a place as far away from light pollution as you can. With a manual camera, try setting 25 second exposure, f/2.8, ISO 1600 (you can experiment with these settings). You’ll need a tripod to keep your camera stable during the exposure. Modern smartphones can produce impressive results as well. There are free apps available to download that automatically take a series of short exposures for you and add them together to create a long night-time photo.

    If you have access to a telescope, you can hold your smartphone up to the eyepiece of the telescope and take your shot, this is known as afocal photography – where the lens takes the place of the human eye.

    There are plenty of tips for getting started in astrophotography, just do a search online and you’ll be exposed to a wealth of information.

    See the full article here .

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    Liverpool John Moores University is a public research university[6] in the city of Liverpool, England. It has 21,875 students, of which 18,375 are undergraduate students and 3,500 are postgraduate, making it the 33rd largest university in the UK by total student population.

    The university can trace its origins to the Liverpool Mechanics’ School of Arts, established in 1823 making it a contestant as the third-oldest university in England; this later merged to become Liverpool Polytechnic. In 1992, following an Act of Parliament the Liverpool Polytechnic became what is now Liverpool John Moores University.

    It is a member of the University Alliance, a mission group of British universities which was established in 2007.[9] and the European University Association.

  • richardmitnick 2:04 pm on April 24, 2017 Permalink | Reply
    Tags: , , , Basic Research, , Is TRAPPIST-1 Really Moonless?, Worlds Without Moons   

    From AAS NOVA: ” Worlds Without Moons” 


    American Astronomical Society

    24 April 2017
    Susanna Kohler

    Many exoplanets are expected to host moons — but can planets in compact systems orbiting close to their host stars do so? [NASA/JPL-Caltech]

    Many of the exoplanets that we’ve discovered lie in compact systems with orbits very close to their host star. These systems are especially interesting in the case of cool stars where planets lie in the star’s habitable zone — as is the case, for instance, for the headline-making TRAPPIST-1 system.

    But other factors go into determining potential habitability of a planet beyond the rough location where water can remain liquid. One possible consideration: whether the planets have moons.

    Supporting Habitability

    Locations of equality between the Hill and Roche radius for five different potential moon densities. The phase space allows for planets of different semi-major axes and stellar host masses. Two example systems are shown, Kepler-80 and TRAPPIST-1, with dots representing the planets within them. [Kane 2017]

    Earth’s Moon is thought to have been a critical contributor to our planet’s habitability. The presence of a moon stabilizes its planet’s axial tilt, preventing wild swings in climate as the star’s radiation shifts between the planet’s poles and equator. But what determines if a planet can have a moon?

    A planet can retain a moon in a stable orbit anywhere between an outer boundary of the Hill radius (beyond which the planet’s gravity is too weak to retain the moon) and an inner boundary of the Roche radius (inside which the moon would be torn apart by tidal forces). The locations of these boundaries depend on both the planet’s and moon’s properties, and they can be modified by additional perturbative forces from the host star and other planets in the system.

    In a new study, San Francisco State University scientist Stephen R. Kane modeled these boundaries for planets specifically in compact systems, to determine whether such planets can host moons to boost their likelihood of habitability.

    Allowed moon density as a function of semimajor axis for the TRAPPIST-1 system, for two different scenarios with different levels of perturbations. The vertical dotted lines show the locations of the six innermost TRAPPIST-1 planets. [Kane 2017]

    Challenge of Moons in Compact Systems

    Kane found that compact systems have a harder time supporting stable moons; the range of radii at which their moons can orbit is greatly reduced relative to spread-out systems like our own. As an example, Kane calculates that if the Earth were in a compact planetary system with a semimajor axis of 0.05 AU, its Hill radius would shrink from being 78.5 times to just 4.5 times its Roche radius — greatly narrowing the region in which our Moon would be able to reside.

    Image of the Moon as it transits across the face of the Sun, as viewed from the Stereo-B spacecraft (which is in an Earth-trailing orbit). [NASA]

    Kane applied his models to the TRAPPIST-1 system as an example, demonstrating that it’s very unlikely that many — if any — of the system’s seven planets would be able to retain a stable moon unless that moon were unreasonably dense.

    Is TRAPPIST-1 Really Moonless?

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile interior

    How do these results fit with other observations of TRAPPIST-1? Kane uses our Moon as an example again: if we were watching a transit of the Earth and Moon in front of the Sun from a distance, the Moon’s transit depth would be 7.4% as deep as Earth’s. A transit of this depth in the TRAPPIST-1 system would have been detectable in Spitzer photometry of the system — so the fact that we didn’t see anything like this supports the idea that the TRAPPIST-1 planets don’t have large moons.

    On the other hand, smaller moons (perhaps no more than 200–300 km in radius) would have escaped detection. Future long-term monitoring of TRAPPIST-1 with observatories like the James Webb Space Telescope or 30-meter-class ground-based telescopes will help constrain this possibility, however.


    Stephen R. Kane 2017 ApJL 839 L19. doi:10.3847/2041-8213/aa6bf2

    There are further referenced articles of interest on the full article.

    See the full article here .

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  • richardmitnick 10:08 am on April 24, 2017 Permalink | Reply
    Tags: , , Basic Research, , , What's The Largest Planet In The Universe?, What's the upper limit to planetary size?   

    From Ethan Siegel: “What’s The Largest Planet In The Universe?” 

    Ethan Siegel
    Apr 24, 2017

    ATG medialab, ESA

    There’s a large difference between a planet and a star, but some planets can be significantly larger than anything we find in our own Solar System.

    In our Solar System, Jupiter is the largest planet we have, but what’s the upper limit to planetary size?

    Lunar and Planetary Institute

    Jupiter may be the largest and most massive planet in the Solar System, but adding more mass to it would only make it smaller.

    If you get too much mass together in a single object, its core will fuse lighter elements into heavier ones.

    NASA, ESA, and G. Bacon (STScI)

    It takes about 75-80 times as much mass as Jupiter to initiate hydrogen burning in the core of an object, but the line between a planet and a star is not so simple.

    At about eighty times the mass of Jupiter, you’ll have a true star, burning hydrogen into helium.


    Brown dwarfs, between about 13-80 solar masses, will fuse deuterium+deuterium into helium-3 or tritium, remaining at the same approximate size as Jupiter but achieving much greater masses. Note the Sun is not to scale and would be many times larger.


    Gliese 229 is a red dwarf star, and is orbited by Gliese 229b, a brown dwarf, that fuses deuterium only. Although Gliese 229b is about 20 times the mass of Jupiter, it’s only about 47% of its radius.

    This line — between a gas giant and a brown dwarf — defines the most massive planet.

    Chen and Kipping, 2016, via https://arxiv.org/pdf/1603.08614v2.pdf

    Planetary size peaks at a mass between that of Saturn and Jupiter, with heavier and heavier worlds getting smaller until true nuclear fusion ignites and a star is born.

    In terms of physical size, however, brown dwarfs are actually smaller than the largest gas giants.

    NASA Ames / W. Stenzel; Princeton University / T. Morton

    Jupiter may only be about 12 times Earth’s diameter, but the largest planets of all are actually less massive than Jupiter, with more massive ones shrinking as more mass is added.

    Above a certain mass, the atoms inside large planets will begin to compress so severely that adding more mass will actually shrink your planet.

    Wikimedia Commons user MarioProtIV

    The exoplanet Kepler-39b is one of the most massive ones known, at 18 times the mass of Jupiter, placing it right on the border between planet and brown dwarf. In terms of radius, however, it’s only 22% larger than Jupiter.

    This happens in our Solar System, explaining why Jupiter is three times Saturn’s mass, but only 20% physically larger.

    Wikimedia Commons user Kelvinsong

    A cutaway of Jupiter’s interior. If all the atmospheric layers were stripped away, the core would appear to be a rocky Super-Earth. Planets that formed with fewer heavy elements can be a lot larger and less dense than Jupiter.

    But many solar systems have planets made out of much lighter elements, without large, rocky cores inside.

    NASA/ESA Hubble

    WASP-17b is one of the largest planets confirmed not to be a brown dwarf. Discovered in 2009, it is twice the radius of Jupiter, but only 48.6% of the mass. Many other ‘puffy’ planets are comparably large, but none are yet significantly larger.

    As a result, the largest planets can be up to twice as big as Jupiter before becoming stars.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

  • richardmitnick 9:23 am on April 24, 2017 Permalink | Reply
    Tags: , , , Basic Research, Breaking Planet Chains and Cracking the Kepler Dichotomy, , Kepler Dichotomy, , Planetary migration   

    From astrobites: “Breaking Planet Chains and Cracking the Kepler Dichotomy” 

    Astrobites bloc


    Apr 24, 2017
    Michael Hammer

    Title: Breaking the Chains: Hot Super-Earth systems from migration and disruption of compact resonant chains
    Authors: Andre Izidoro, Masahiro Ogihara, Sean N. Raymond, Alessandro Morbidelli, Arnaud Pierens, Bertram Bitsch, Christophe Cossou, Franck Hersant
    First Author’s Institution: Laboratoire d’astrophysique de Bordeaux, University of Bordeaux

    Status: Submitted to MNRAS [open access]

    To migrate, or not to migrate? That is the question. Of course, since planets are not Shakespearean characters, they should not have a choice! When a planet forms in a disk, it creates two spiral waves: a weaker one ahead of the planet that drags it forward (sending the planet outwards), and a stronger one behind the planet that pulls it backwards (sending the planet inwards). Ultimately, every planet should migrate inwards and in most cases, end up much closer to its star than where it formed.

    When planets in the outer disk migrate inwards faster than planets closer in, they start to catch up to each other. As these planets get closer together, they eventually become gravitationally locked into resonance: pairs of orbits where the outer planet takes exactly twice as long (or another integer ratio such as 3-to-2, etc.) to complete an orbit around its star as the inner one. Once this happens, the planets migrate together, maintaining that 2-to-1 ratio. In systems with many rocky planets, the third one will follow suit and fall into a resonance with the second planet, as will the fourth with the third, and so on. Eventually, the system will have a long chain of up to 10 resonant rocky planets tightly packed in the inner part of the disk!

    Yet even though migration is supposed to be inevitable, only about 5% of the planetary systems discovered by the Kepler mission are actually in this setup (TRAPPIST-1 is the most famous).

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    The other 95% are not, many of which because they only have one planet. Today’s paper, led by Andre Izidoro, attempts to explain these discrepancies by suggesting that all systems migrate into resonant chains, but not all of them stay in resonant chains!

    Two-Phase Setup

    Izidoro et al. study this problem by conducting two-phase N-body simulations of 120 hypothetical planetary systems with 20 to 30 rocky planets for 100 Myr. These planets start out with 0.1 to 4.5 Earth masses and are spread out evenly in the outer disk beyond 5 AU.

    In phase one (0 to 5 Myr), the planets may migrate due to the presence of a gaseous protoplanetary disk. Meanwhile, the disk also keeps the planets on flat, circular orbits by damping the planets’ eccentricities and inclinations.
    In phase two (5 to 100 Myr), the planets can no longer migrate since the disk has dissipated away. However, they are free to develop eccentric and inclined orbits since they are now controlled by interactions with each other instead of interactions with the disk.

    Compact, but not too compact

    Izidoro et al. find that all of their planetary systems migrate into compact resonant chains within 1.5 Myr, safely less than the disk’s lifetime of 5 Myr. Many of these systems (40%) then survive as resonant chains for the entire 100 Myr simulation.

    However, some systems (60%) become too compact (see Figure 1). In particular, the ones that are too compact with higher mass planets become unstable after the disk fades away! The resonant chains then collapse as some of the planets eject and the rest spread farther apart. As they spread out, the surviving planets’ orbits also become more eccentric and inclined.

    Figure 1. Two example resonant chains after phase one. The first system (left) will survive phase two (without the disk). The second system (right) will become unstable because it has more planets too close together. Some of the surviving planets will develop inclined orbits, making them less likely to transit. Adapted from Figs. 2 and 3 of the paper.

    Single-Planet Imposters

    In order to compare their results with actual exoplanet systems discovered by the Kepler Mission, Izidoro et al. must determine what fraction of their planets can transit (and be “detected” by Kepler).

    Planet transit. NASA/Ames

    NASA/Kepler Telescope

    They find that in the stable resonant chains, Kepler can detect 3 or more planets in 66% of these systems. On the other side in the unstable systems, the inclined orbits from the instabilities make it so that Kepler can only detect 1 planet in 78% of these systems, even though over 90% of the unstable systems still have multiple planets.

    Explaining the Kepler Dichotomy

    One of the defining features of Kepler’s planets is the large number of systems with only one transiting planet. Naturally, we expected that Kepler would not be able to find all of the planets in each of its systems since planets at large separations from their star that do not line up with our line-of-sight will not transit. However even with this bias, the fact that there are so many more single-planet systems than two-planet systems (see Figure 2) suggests that Kepler systems belong to a dichotomy: roughly 50% of all systems have just one planet (including non-transiting ones) and 50% have many planets (5+ for small stars). Such a high fraction of single-planet systems is a huge surprise, given how many planets exist in our own solar system.

    However, the two populations of planetary systems in this study offer an explanation for the Kepler dichotomy that would imply these single planets are not so lonely. Izidoro et al. calculate that if no more than 25% of all planetary systems are compact resonant chains (with the rest being unstable systems), this distribution of systems can match the high fraction of systems with just one transiting planet in the Kepler dichotomy — even though nearly all of these systems would have multiple planets.

    Figure 2. Comparison of Kepler’s planetary systems to this paper’s planetary systems. In the Kepler sample (green), the vast majority of systems have only one transiting planet. The unstable systems in this paper (blue) would have even more single-transit systems, while the stable resonant chains (red) have a lot fewer. A proper balance between these two (90% unstable, 10% stable — gray) matches the Kepler dichotomy pretty well. Fig. 15 of the paper.

    Why so unstable?

    Izidoro et al. expect that in reality, roughly 5% of all planetary systems are stable resonant chains (since this is the fraction found by Kepler), which is consistent with their upper limit of 25% they need to explain the dichotomy. Even though the authors find that 40% remain stable in their study, they suspect that simulations with a more realistic protoplanetary disk would lead to many more systems going unstable. Nonetheless, the authors caution that their model remains incomplete until they find a reason for ~95% of Kepler’s systems becoming unstable at some point in their history.

    It may also be the case that not all systems migrate into resonant chains to begin with, or even that planets do not migrate as easily as this study presumes. For now, we can still take solace in knowing that at least some of Kepler’s single-planet systems have non-transiting companions that they can orbit with for billions of years.

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

  • richardmitnick 7:21 am on April 24, 2017 Permalink | Reply
    Tags: , Basic Research, , , , Natalie Batalha,   

    From Many Worlds: Women in STEM – “The Influential Natalie Batalha” 

    NASA NExSS bloc


    Many Words icon

    Many Worlds

    Marc Kaufman

    Natalie Batalha, project scientist for the Kepler mission and a leader of NASA’s NExSS initiative on exoplanets, was just selected as one of Time Magazine’s 100 most influential people in the world. (NASA, TIME Magazine.)

    I’d like to make a slight detour and talk not about the science of exoplanets and astrobiology, but rather a particular exoplanet scientist who I’ve had the pleasure to work with.

    The scientist is Natalie Batalha, who has been lead scientist for NASA’s landmark Kepler Space Telescope mission since soon after it launched in 2009, has serves on numerous top NASA panels and boards, and who is one of the scientists who guides the direction of this Many Worlds column.

    Last week, Batalha was named by TIME Magazine as one of the 100 most influential people in the world. This is a subjective (non-scientific) calculation for sure, but it nonetheless seems credible to me and to doubtless many others.

    Batalha and the Kepler team have identified more than 2500 exoplanets in one small section of the distant sky, with several thousand more candidates awaiting confirmation. Their work has once and for all nailed the fact that there are billions and billions of exoplanets out there.

    “NASA is incredibly proud of Natalie,” said Paul Hertz, astrophysics division director at NASA headquarters, after the Time selection was announced.

    “Her leadership on the Kepler mission and the study of exoplanets is helping to shape the quest to discover habitable exoplanets and search for life beyond the solar system. It’s wonderful to see her recognized for the influence she has had on the world – and on the way we see ourselves in the universe.”

    And William Borucki, who had the initial idea for the Kepler mission and worked for decades to get it approved and then to manage it, had this to say about Batalha:

    “She has made major contributions to the Kepler Mission throughout its development and operation. Natalie’s collaborative leadership style, and expert knowledge of the population of exoplanets in the galaxy, will provide guidance for the development of successor missions that will tell us more about the habitability of the planets orbiting nearby stars.”

    Batalha has led the science mission of the Kepler Space Telescope since it launched in 2009. (NASA)

    As a sign of the perceived importance of exoplanet research, two of the other TIME influential 100 are discoverers of specific new worlds. They are Guillem Anglada-Escudé (who led a team that detected a planet orbiting Proxima Centauri) and Michael Gillon (whose team identified the potentially habitable planets around the Trappist-1 system.)

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets, NASA announced on Wednesday. (NASA)

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile interior

    But Batalha, and no doubt the other two scientists, stress that they are part of a team and that the work they do is inherently collaborative. It absolutely requires that many others also do difficult jobs well.

    For Batalha, working in that kind of environment is a natural fit with her personality and skills. Having watched her at work many times, I can attest to her ability to be a strong leader with extremely high standards, while also being a kind of force for calm and inclusiveness.

    We worked together quite a bit on the establishing and running of this column, which is part of the NASA Nexus for Exoplanet System Science (NExSS) initiative to encourage interdisciplinary thinking and collaboration in exoplanet science.

    It was NASA’s astrobiology senior scientist Mary Voytek who set up the initiative and saw fit to start this column, and it was Batalha (along with several others) who helped guide and focus it in its early days.

    I think back to her patience. I was visiting her at NASA’s Ames Research Center in Silicon Valley and talking shop — meaning stars and planets and atmospheres and the like. While I had done a lot of science reporting by that time, astronomy was not a strong point (yet.)

    So in conversation she made a reference to stars on the Hertzsprung-Russell diagram and I must have had a somewhat blank look to me. She asked if I was familiar with Hertzsprung-Russell and I had to confess that I was not.

    Not missing a beat, she then went into an explanation of what is a basic feature of astronomy, and did it without a hint of impatience. She just wanted me to know what the diagram was and what it meant, and pushed ahead with good cheer to bring me up to speed — as I’m sure she has done many other times with many people of different levels of exposure to the logic and complexities of her very complex work.

    Hertzsprung–Russell diagram with 22,000 stars plotted from the Hipparcos Catalogue and 1,000 from the Gliese Catalogue of nearby stars. Stars tend to fall only into certain regions of the diagram. The most prominent is the diagonal, going from the upper-left (hot and bright) to the lower-right (cooler and less bright), called the main sequence. In the lower-left is where white dwarfs are found, and above the main sequence are the subgiants, giants and supergiants. The Sun is found on the main sequence at luminosity 1 (absolute magnitude 4.8) and B−V color index 0.66 (temperature 5780 K, spectral type G2V). Wikipedia

    (Incidently, the Hertzsprung-Russell diagram plots each star on a graph measuring the star’s brightness against its temperature or color.)

    I mention this because part of Batalha’s influence has to do with her ability to communicate with individuals and audiences from the lay to the most scientifically sophisticated. Not surprisingly, she is often invited to be a speaker and I recommend catching her at the podium if you can.

    By chance — or was it chance? — the three exoplanet scientists selected for the Time 100 were at Yuri Milner’s Breakthrough Discuss session Thursday when the news came out. On the left is Anglada-Escude, Batalha in the middle and Gillon on the right.

    Batalha was born in Northern California with absolutely no intention of being a scientist. Her idea of a scientist, in fact, was a guy in a white lab coat pouring chemicals into a beaker.

    As a young woman, she was an undergrad at the University of California at Berkeley and planned on going into business. But she had always been very good and advanced in math, and so she toyed with other paths. Then, one day, astronaut Rhea Setton came to her sorority. Setton had been a member of the same sorority and came to deliver a sorority pin she had taken up with during on a flight on the Space Shuttle.

    “That visit changed my path,” Batalha told me. “When I had that opportunity to see a woman astronaut, to see that working for NASA was a possibility, I decided to switch my major — from business to physics.”

    After getting her BA in physics from UC Berkeley, she continued in the field and earned a PhD in astrophysics from UC Santa Cruz. Batalha started her career as a stellar spectroscopist studying young, sun-like stars. Her studies took her to Brazil, Chile and, in 1995, Italy, where she was present at the scientific conference when the world learned of the first planet orbiting another star like our sun — 51 Pegasi b.

    It had quite an impact. Four years later, after a discussion with Kepler principal investigator Borucki at Ames about challenges that star spots present in distinguishing signals from transiting planets, she was hired to join the Kepler team. She has been working on the Kepler mission ever since.

    Asked how she would like to use her now publicly acknowledged “influence,” she returned to her work on the search for habitable planets, and potentially life, beyond earth.

    “We’ve seen that there’s such a keen public interest and an enormous scientific interest in terms of habitable worlds, and we have to keep that going,” she said. “This is a very hard problem to solve, and we need all hands on deck.”

    She said the effort has to be interdisciplinary and international to succeed, and she pointed to the two other time 100 exoplanet hunters selected. One is from Belgium and the other is working in the United Kingdom, but comes from Spain.

    When the nominal Kepler mission formally winds down in September, she says she looks forward to more actively engaging with the exoplanet science Kepler has made possible.

    The small planets identified by Kepler as of one year ago that are small and orbit in the region around their star where water can exist as a liquid. NASA Ames/N. Batalha and W. Stenzel

    Batalha’s role in the NASA NExSS initiative offers a window into what makes her a leader — she excels at making things happen.

    Voytek and Shawn Domogal-Goldman of Goddard founded and oversee the group. They then chose Batalha two other leaders (Anthony Del Genio of the Goddard Institute for Space Studies and Dawn Gelino of NASA Exoplanet Science Institute ) to be the hands-on leaders of the 18 groups of scientists from a wide variety of American universities.

    (Asked why she selected Batalha, Voytek replied, “TIME is recognizing what motivated us to select her as one of the leaders for….NExSS. Her scientific and leadership excellence.”)

    This is the official NExSS task: “Teams will help classify the diversity of worlds being discovered, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Scientists are developing ways to identify habitable environments on these worlds and search for biosignatures, or signs of life. Central to the work of NExSS is understanding how biology interacts with the atmosphere, surface, oceans, and interior of a planet, and how these interactions are affected by the host star.”

    She has encouraged and helped create the kinds of collaborations that these tasks have made essential, but also helped identify upcoming problems and opportunities for exoplanet research and has started working on ways to address them. For instance, it became clear within the NExSS group and larger community that many, if not most exoplanet researchers would not be able to effectively apply for time to use the James Webb Space Telescope (JWST) for several years after it launched in late 2018.

    NASA/ESA/CSA Webb Telescope annotated

    To be awarded time on the telescope, researchers have to write detailed descriptions of what they plan to do and how they will do it. But how the giant telescope will operate in space is not entirely know — especially as relates to exoplanets. So it will be impossible for most researchers to make proposals and win time until JWST is already in space for at least two of its five years of operation.

    Led by Batalha, exoplanet scientists are now hashing out a short list of JWST targets that the community as a whole can agree should be the top priorities scientifically and to allow researchers to learn better how JWST works. As a result, they would be able to propose their own targets for research much more quickly in those early years of JWST operations. It’s the kind of community consensus building that Batalha is known for.

    She also has an important roles in the NASA Astrophysics Advisory Committee and hopes to use the skills she developed working with Kepler on the upcoming Transiting Exoplanet Survey Satellite (TESS) mission.


    Batalha preparing for the Science Walk in San Francisco on Earth Day.

    A mother of four (including daughter Natasha, who is on her way to also becoming an accomplished astrophysicist), Batalha is active on Facebook sharing her activities, her often poetic thoughts, and her strong views about scientific and other issues of the day.

    She was an active participant, for instance, in the National March for Science in San Francisco, posting photos and impressions along the way. I think it’s fair to say her presence was noticed with appreciation by others.

    And that returns us to what she considers to be some of her greatest potential “influence” — being an accomplished, high ranking and high profile NASA female scientist.

    “I don’t have to stand up and say to young women ‘You can do this.’ You can just exist doing your work and you become a role model. Like Rhea Setton did with me.”

    And it is probably no coincidence that four other senior (and demanding) positions on the Kepler mission are filled by women — two of whom were students in classes taught some years ago by Natalie Batalha.

    See the full article here .

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    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

  • richardmitnick 9:54 am on April 23, 2017 Permalink | Reply
    Tags: , , Basic Research, Computer modelling, , , , , Modified Newtonian Dynamics, or MOND, , Simulating galaxies,   

    From Durham: “Simulated galaxies provide fresh evidence of dark matter” 

    Durham U bloc

    Durham University

    21 April 2017
    No writer credit

    A simulated galaxy is pictured, showing the main ingredients that make up a galaxy: the stars (blue), the gas from which the stars are born (red), and the dark matter halo that surrounds the galaxy (light grey). No image credit.

    Further evidence of the existence of dark matter – the mysterious substance that is believed to hold the Universe together – has been produced by Cosmologists at Durham University.

    Using sophisticated computer modelling techniques, the research team simulated the formation of galaxies in the presence of dark matter and were able to demonstrate that their size and rotation speed were linked to their brightness in a similar way to observations made by astronomers.

    One of the simulations is pictured, showing the main ingredients that make up a galaxy: the stars (blue), the gas from which the stars are born (red), and the dark matter halo that surrounds the galaxy (light grey).

    Alternative theories

    Until now, theories of dark matter have predicted a much more complex relationship between the size, mass and brightness (or luminosity) of galaxies than is actually observed, which has led to dark matter sceptics proposing alternative theories that are seemingly a better fit with what we see.

    The research led by Dr Aaron Ludlow of the Institute for Computational Cosmology, is published in the academic journal, Physical Review Letters.

    Most cosmologists believe that more than 80 per cent of the total mass of the Universe is made up of dark matter – a mysterious particle that has so far not been detected but explains many of the properties of the Universe such as the microwave background measured by the Planck satellite.

    CMB per ESA/Planck


    Convincing explanations

    Alternative theories include Modified Newtonian Dynamics, or MOND. While this does not explain some observations of the Universe as convincingly as dark matter theory it has, until now, provided a simpler description of the coupling of the brightness and rotation velocity, observed in galaxies of all shapes and sizes.

    The Durham team used powerful supercomputers to model the formation of galaxies of various sizes, compressing billions of years of evolution into a few weeks, in order to demonstrate that the existence of dark matter is consistent with the observed relationship between mass, size and luminosity of galaxies.

    Long-standing problem resolved

    Dr Ludlow said: “This solves a long-standing problem that has troubled the dark matter model for over a decade. The dark matter hypothesis remains the main explanation for the source of the gravity that binds galaxies. Although the particles are difficult to detect, physicists must persevere.”

    Durham University collaborated on the project with Leiden University, Netherlands; Liverpool John Moores University, England and the University of Victoria, Canada. The research was funded by the European Research Council, the Science and Technology Facilities Council, Netherlands Organisation for Scientific Research, COFUND and The Royal Society.

    See the full article here .

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    Durham U campus

    Durham University is distinctive – a residential collegiate university with long traditions and modern values. We seek the highest distinction in research and scholarship and are committed to excellence in all aspects of education and transmission of knowledge. Our research and scholarship affect every continent. We are proud to be an international scholarly community which reflects the ambitions of cultures from around the world. We promote individual participation, providing a rounded education in which students, staff and alumni gain both the academic and the personal skills required to flourish.

  • richardmitnick 9:14 am on April 23, 2017 Permalink | Reply
    Tags: Basic Research, Doppel, Fotini Markopoulou, ,   

    From Nautilus: “This Physics Pioneer Walked Away from It All” 



    July 28, 2016
    Sally Davies
    Illustrations by Ping Zhu
    Photography by Tom Jamieson

    Inside the South London offices of Doppel, a wearable technology start-up, sandwiched into a single room on a floor between a Swedish coffee shop and a wig-making studio, CEO and quantum physicist Fotini Markopoulou is debating the best way to describe an off-switch.

    Doppel: the wearable heartbeat that works with your body

    Markopoulou and her three co-founders have gathered in convivial discomfort around a cluttered formica table and lean-to blackboard. They’re redesigning the features of their eponymous first device, which is due to be released in October. It’s a kind of elegant watch that sits on the inside of your wrist and delivers a regular, vibrating pulse. By mimicking a heartbeat, the Doppel helps regulate a person’s emotions and mental focus.

    Swiveling in a chair, Markopoulou says she likes a “smothering” gesture—placing a palm over the face of the Doppel to turn it off—because it is intuitive and simple, and the term suggests the device is “alive.” “You could always murder it,” deadpans commercial director Jack Hooper. Head of technology Andreas Bilicki chimes in. “Why not ‘choke’ or ‘asphyxiate’?” The team throws around alternatives: “throttle”; “go to sleep, to sleep”; “turn your Doppel off, just like putting a blanket over a parrot’s cage.”

    A NEW BEAT: Fotini Markopoulou at work at Doppel, the wearable technology startup she co-founded, after saying goodbye to theoretical physics.

    Markopoulou, 45, observes the banter with a half-smile. She is fine-featured and striking. Her heavy-lidded eyes anchor a gaze that seems wary of its own powers, as if her promiscuous intelligence must hold itself back from latching on to your every word. She wears her hair in a tousled pixie-cut, and on this spring day, a green knit sweater and blue scarf with a pattern of fish-like scales. There are no airs about her, nor any indication that she’s 20 years older than the rest of the team. Markopoulou lives in Oxford but sleeps on design director Nell Bennett’s couch whenever she comes down to London.

    After the meeting, Markopoulou and I walk downstairs to get a coffee. With the zeal of the reborn, she tells me how much she relishes the pleasures of making a product that people will use and pay for. “There is a very 
practical satisfaction to getting stuff done, whether it’s making something or selling something,” she says. “I do enjoy solving practical problems, like how to convince people Doppel’s a good idea, or how to get the right deal from an accountant.”

    It’s hard to see how these tasks could fully absorb Markopoulou. She is one of the most radical and fiercely creative theoretical physicists alive today, and a founding faculty member of the Perimeter Institute for Theoretical Physics in Waterloo, Canada, where she was at the vanguard of quantum gravity.

    Perimeter Institute in Waterloo, Canada

    This is the branch of physics striving to unify the two most fundamental theories of the universe: general relativity, proposed by Einstein, and quantum mechanics.

    Quantum theory describes the rowdy interactions of fundamental particles that govern many of the forces in the known universe—except gravity. Gravity is rendered beautifully predictable by general relativity, which envisions it as an effect of how the four dimensions of space and time curve in response to matter, like a piece of tarpaulin bending under a bowling ball. Quantum theory’s ability to predict the behavior of an electron in a magnetic field has been described as the most precisely tested phenomenon in the history of science. But putting it together with gravity has so far produced absurd mathematical results. It’s as if a soccer player and a tennis player were managing to carry on a game despite being ignorant of the opponent’s rules.

    After years of single-minded study, Markopoulou co-created a novel potential solution known as “quantum graphity.” This model of the universe operates at a scale that is tiny even by subatomic standards—as tiny in relation to a speck of dust as a speck of dust is to the entire universe. It suggests that space itself and its attendant laws and features could evolve out of interconnected dots to create the dimensions we experience as space, like a soufflé rising from a pan.

    “Fotini is extremely original, original to a fault,” says Lee Smolin, a fellow founder of Perimeter who used to be married to Markopoulou. “Most scientists pick up on ideas which are dominant, which come from living figures, and develop them incrementally. She doesn’t do that—she works solely on her own ideas.”

    Between sips of a latte, Markopoulou describes how theoretical physics consumed her. “It’s a lot like being in a monastery, like no normal human needs should make you waver from the cause of understanding where the universe came from,” she says. “In my previous eyes, just leaving is a moral failure, more than anything else. It’s a devotion thing—your devotion has just gone.” She pauses to shape her next thought. “It’s also not really a loss of faith; I changed.”

    GOT RHYTHM?: Markopoulou oversaw the design and engineering of the Doppel, which sends a mood-affecting pulse to a wearer’s wrist, from prototype to product.

    Five years after walking away from physics, Markopoulou is still trying to explain that change to herself. She was forced to re-examine her position when Perimeter’s new director, Neil Turok, who joined in 2008, deemed her work too speculative and squeezed her out of the Institute. But her unease had deeper roots.

    Working in a field where the air of reality was so thin, Markopoulou started to lose touch with her own life. “I have so many friends in their late 40s, and they still don’t have an actual home or a family or anything. As long as they have a place where they can go and think they’re happy.” She casts a wry smile. “I failed that test, obviously. For a lot of people that makes sense, and even for me that makes sense 80 percent. It’s that other 20 percent that causes problems.”

    Doppel embodies many of the qualities that Markopoulou came to miss in her work as a physicist. The company is grounded in psychophysiology, a field which considers the mind to be deeply rooted in the body and its environment. But embracing the fact that the self is interwoven with the world, and at its mercy, is a frightening thought, Markopoulou says. Escaping that fear, and trying to pin down the interconnection between humans and the natural systems that make us what we are, is what drew her to physics in the first place.

    “I did appreciate, for a long time, the way science detaches you from that scariness, because you ignore it,” Markopoulou says. “Between the truth of the physical world and a physics theory, there’s humans. Of course, nothing happens there, because removing the person is the whole point of training as a scientist.” A pause. “But this may or may not be possible.”

    As a teenager growing up in Athens, Greece, Markopoulou looked like an ordinary kid: permed hair, heavy ribbed sweaters, a penchant for Clint Eastwood Westerns. But she was already attracted to the study of transcendent truths. On her way home from school, she would sometimes drop in at Greek orthodox churches to lie on her back in the pews, and contemplate the elaborate scenes of stars and angels painted into the interior domes. One summer, when she was 15, she happened across a book in the library of the British Council with the title Starseekers, a quasi-mystical account of the history of cosmology, by English writer Colin Wilson. “I got totally obsessed with that book,” Markopoulou says. She convinced her mother, Maria, to buy her an Atari computer, and spent hours trying to translate Starseekers into Greek on a word processor.

    Markopoulou lived with her mother in a cramped two-story studio in Athens, where Maria worked as a figurative sculptor. She was a magnetic, troubled figure, unafraid to set her own moral compass but riven with internal conflicts. She’d fallen pregnant one summer to a Greek sculptor she had known in Florence, where she trained as an artist against the wishes of her parents, and decided to raise the baby as a single mother in Athens. She was 33. “Her lovely way of putting this was, ‘Jesus was also 33 when he was put on the cross,’ ” Markopoulou says. “But it was also very clear that I was the best thing that had ever happened to her.” (Markopoulou has never met and knows little about her father, who died in 1997.)

    Markopoulou loved accompanying Maria to exhibitions and openings, but struggled to disentangle her sense of self from her mother’s strong and particular judgments. “My mother’s relation with reality, it would be wrong to say that it wasn’t solid, but it was just different,” Markopoulou says. Maria hated to sleep and refused to have a bed: “My mother clearly thought that sleeping was like dying, and that she might not wake up if she did, and something like a bed might as well have been a tombstone. I did realize as I was growing up that you couldn’t rely on her description of something.”

    The subjectivity of aesthetic merit troubled Markopoulou. “One of the things I hated about the art-world is that decision-making is quite arbitrary,” she says. “People could say Picasso is shit just because they felt like saying it. I found that very frustrating, and very political; they’re gatekeepers, and then your life and self-perception is a function of those gatekeepers.”

    Markopoulou’s education in Greece was “a complete disaster,” she says, with teachers whose instruction consisted of reading the newspaper at the front of the classroom. In her final year of high school, Markopoulou went in search of private evening classes; by mistake, she walked through the door of an institution that offered A-levels, the exams for students entering the British university system. She hadn’t considered studying in the United Kingdom, but ended up enrolling. “The usual story about people in quantum gravity is, ‘I read about Einstein when I was 8,’ ” she says. That was not her. The pendulum for her imaginary career had swung between being an astronaut and an archeologist. She only selected theoretical physics under the pressure of her university application, and chose the course on the casual advice of a tutor at the school, a former NASA scientist, who said it would be a good balance for her aptitude in physics and mathematics.

    Markopoulou failed her A-levels—“the first time I walked into the lab was for the exam, and half the questions I answered in Greek”—but, as part of the clearing process between teachers and universities, her tutor secured her a place at Queen Mary’s University in London, her first choice. The department had several excellent particle physicists investigating the top quark, but the place retained the welcoming atmosphere of institutions unburdened by hallowed reputations.

    Money was tight, so Markopoulou didn’t have much of a social life. She planned birthday parties at McDonald’s for a bit of extra cash, while her mother, who was living with her in London to get the rent from her studio in Athens, repaired antiques. (They would continue to live together until the last year of Markopoulou’s Ph.D.) But Markopoulou loved it all the same. She and a clutch of the other undergraduates would relax in the chapel café between lectures, and occasionally head out in the evenings to hear one of their professors play amateur hard rock. At the same time, in her classes, she got wind of the fact that “there was some forbidden place”—that when it came to certain subjects, such as why time moves in one direction, it was better not to ask. She was not content with what the rules were; she wanted to know how they came to be.

    Toward the end of her undergraduate degree, a friend suggested Markopoulou attend a lecture on quantum gravity by Chris Isham, a rigorously mathematical physicist at Imperial College. He was also a Jungian analyst and devout Christian, with the air of a mystic and a fondness for peppering his lectures with passages from T.S. Eliot and Heidegger. “You can’t take out of the world the fact we see it,” Isham tells me. “What is the reality we hang onto? Well, it’s us, but who are we that sit inside this space which is relative to us?”

    Isham was the first person Markopoulou encountered who could relate the technical dimensions of science to humans’ wider search for meaning. “Sometimes doing physics can be a bit like doing plumbing—you have your equations and tools and you go around and fix stuff, and if you do it in a smart way, people respect you,” she says. “Because you are a professional physicist, you get used to the idea that there are difficult questions that you do not do for a living. But these are what drove most of us to join the ranks.”

    Markopoulou was developing her own clear vision of what she wanted to achieve as a physicist. “I am not going to devote my life to something because it’s beautiful—it’s this quest for the truth,” she says. “Science is not philosophy—there is not a lot of value in thinking about questions if you cannot come up with answers. But I’ve always been attracted to what is the furthest away you can get such that you can still come back with an answer. You’re trying to find the end of the coil to unfold it.”

    Under Isham’s influence, Markopoulou started to grapple with quantum gravity. Her assigned Ph.D. project was based on a previous paper that examined the movement of dust particles to develop a new approach to splitting time away from the three dimensions of space. This sounds like a solution in search of a problem—surely time is a different thing from space?—until you remember Einstein’s counterintuitive insight that time is intimately interwoven with the fabric of space, and can be similarly twisted and bent by matter and movement. Time is dynamic, and defined by its relationship to what’s happening around it. It follows that there is no absolute time that the whole universe obeys—and more troublingly, when you push the equations far enough, time has a tendency to disappear entirely. “The relativity view of the world is that space and time is out there and it’s more or less a static thing—time is just another dimension,” the distinguished physicist Roger Penrose explains to me.

    However, Einstein’s account of time doesn’t make sense in quantum theory. The quantum realm is host to all sorts of phenomena—particles existing in two places at once, or becoming entangled, as if they’re able to communicate their properties instantly and seemingly telepathically, whether separated by a lab-bench or a light-year. It adopts a version of time that’s far more conventional, like a metronome ticking away in the background, distinct from the bizarre behavior of quantum theory’s zoo of quarks, bosons, and fermions.

    DESIGN NOTES: When she worked on quantum gravity, Markopoulou gave many presentations with graphics. Likewise at Doppel, she and her colleagues post notes to visualize and solve problems.

    It began to dawn on Markopoulou that you might be able to reconcile these two accounts of time by looking more closely at how they viewed space. After her first paper on dust modeling, she turned to spin networks. These are geometric models which help physicists describe quantum interactions in space, and fit more readily with the mathematics of general relativity. Markopoulou had the idea of combining spin networks with a “causal set,” which allows time to be captured as a history of discrete events rather than a continuous flow. Showing how histories could be represented spatially let her bring a more substantive version of time into general relativity—one that wasn’t rigid (as in some accounts of quantum theory) nor completely flexible (as in general relativistic spacetime).

    Her work caught the eye of Smolin, an American theoretical physicist who at the time was visiting Imperial from Penn State University. He’d made a name for himself as a joint inventor of loop quantum gravity theory—a competitor to string theory in the quantum gravity sweepstakes—which was building on spin networks to develop a more sophisticated picture of quantum spacetime. Smolin worked with Markopoulou on a paper on causal sets, and invited her back to Penn State for three months while she was finishing her dissertation. They would marry in 1999.

    At the time, Penn State was a premier institution for non-string quantum gravity, and Markopoulou was surrounded by a number of other brilliant young scientists. “A bunch of different ideas were coming together; there was this sense that you might actually do something faster than the person in the next room, which is very unusual in quantum gravity,” she says. String theory had never appealed to Markopoulou, who saw it as cutthroat and conformist. “String theory has a very strong pecking order,” she says. “It comes with a strong machismo: What complicated stuff can you do? They’re very good at maintaining that.”

    Some of Markopoulou’s contemporaries saw the equations pointing to the conclusion that time is an illusion at the fundamental level, and that what we experience as the progression of events emerges as a byproduct of fluctuations in space. But Markopoulou tended to attack the problem from the other direction—looking at time as the most important thing, and space as something that grows out of it, or is left as a trace, like a logbook of what has taken place in time. “I’m a bit extreme in that I would actually like to keep a fairly old-style time,” Markopoulou says. “I’m not wrong in my views. They come with challenges, but they also come with opportunities.”

    IN HER ELEMENT: At the Perimeter Institute for Theoretical Physics, where she was a founding member, Markopoulou, seen here in 2002, was known as a persuasive, though not forceful, leader. Derek Shapton

    In early 2000, whispers went around the theoretical physics community that somebody wanted to donate $100 million for an institute dedicated to foundational physics. Markopoulou and Smolin were approached by Howard Burton, a Canadian with a Ph.D. in theoretical physics from the University of Waterloo, who was the emissary for this Gatsby-like figure. “I genuinely thought the guy was a sociologist studying the reactions of physicists to that statement—the amount of money is crazy for foundational physics,” Markopoulou says. By now she was doing a postdoctoral fellowship at the Max Planck Institute for Gravitational Physics in Berlin. She and Smolin were flown in secrecy to Canada and only informed that the donor was Mike Lazaridis, the founder of Blackberry, on the drive from the airport: “We spent the night at Mike’s house, where he made us French toast and talked us into coming to Waterloo.”

    By the time Perimeter was set up, she and Smolin had separated, but remained friends—which was just as well. To lay the scientific groundwork for the institute, the three founding faculty huddled together in a former restaurant, along with several postdoctoral students and Burton, whom Lazaridis had appointed as the director. They inherited the coffee machine and learned to make top-notch barista cappuccinos. The institute aspired to a flat management structure hospitable to free-thinkers, without tenured jobs or the ordinary hierarchies of a university physics department, in the hope that this would foster more interesting research.

    While Markopoulou was not a forceful leader, she was a persuasive one, says Seth Lloyd, a physicist and professor at the Massachusetts Institute of Technology, and a longtime collaborator of Markopoulou’s. He recalls trekking with her and some postdocs in the Sangre de Cristo Mountains, when she was on a fellowship at the Santa Fe Institute in New Mexico. “At each stage of the hike, there were different suggestions about where to go, and we always ended up doing what Fotini thought was a good thing,” he says. “We had a great time, none of us ever thought Fotini was imposing her will—just that what Fotini seemed to want to do was the right thing to do.”

    At Perimeter, Markopoulou was at her best when the learning and experimentation were the quickest. Invariably her work became playful and synthetic. “At some point I thought we should just reduce the whole thing to the basic property of space, which is here and there,” she says. Physicists were willing to toy with the nature of time and “hack” general relativity to create a quantum gravity theory, she says. But they seldom played with the nature of space or “hacked” quantum theory. With Simone Severini, an Italian computer scientist, and graduate student Tomasz Konopka, Markopoulou drew on quantum information theory to develop the notion of quantum graphity. “Fotini thought it was fun—this cute idea, that the universe is a big network, like the London Underground, that changes over time,” Severini says.

    Markopoulou was partly inspired by the principle of emergence, where complexity can emerge from simplicity, or, more to her point, simplicity from complexity, such as wiggling water molecules forming ice crystals or waves. Paramount in her model was the ability to create images that explained “geometrogenesis,” her and her colleagues’ term for the emergence of the structure of spacetime during a critical phase in the birth of the universe. “Once it starts being hard to visualize, I’m not happy, I get uncomfortable,” she says. “I also think you can have an extreme richness while staying with very few building blocks.”

    She was tickled by an aperçu from Ludwig Boltzmann, the 19th-century Austrian physicist, who looked at the physical properties of atoms and said, “Every Tom, Dick, and Harry felt himself called upon to devise his own special combination of atoms and vortices, and fancied in having done so that he had pried out the ultimate secrets of the Creator.” Markopoulou chuckles. “It felt to me, when we were arguing ‘Is it my model? Is it your model?’ we were totally every Tom, Dick, and Harry.”

    In quantum graphity, space evolves out of dots that are either “on” or “off ”—connected or disconnected to the next dot. It doesn’t matter exactly what the dots are; they represent coordinates in a network of relationships, the fundamental constituents of the universe. The idea, Markopoulou explains, comes from a branch of mathematics known as category theory, in which “what something is, is the sum of how it behaves, rather than how it is.” At the highest possible energy, at the beginning of the universe, all the dots in the graph are joined, and no notion of space exists. But as the system cools and loses energy, the points start detaching, which creates the dimensions and laws of space. In this model, space becomes like a crystal that forms out of a liquid as it cools. “The value of this is in trying to give, however primitive it might be, some language to talk about space not being there,” she says.

    “It was very courageous of Fotini to start working on this,” says Sabine Hossenfelder, a research fellow at the Frankfurt Institute for Advanced Studies, a think tank devoted to theoretical physics, who from 2006 to 2009 did postdoc work at Perimeter. “It’s the kind of thing you think has been done long ago, but surprisingly it wasn’t.” It would have been much easier, Hossenfelder says, for Markopoulou to find a niche for herself within an existing theory, like loop quantum gravity. “But quantum graphity of course is much more exciting. It’s a new idea, one that could have done a good job bridging the gap between theory and experiment.”

    No image caption. No image credit.

    As Markopoulou’s reputation grew, she was often called upon to represent Perimeter to the public. She was a young, accomplished woman in physics—a rarity. She enjoyed and tended to accept speaking invitations, partly to help change perceptions of female scientists. “For previous generations, the question was ‘Are there women in science?’ Now there are, but girls want to know, ‘Are they normal?’ When you seem to be happy, and you seem to be a woman they’d be happy to be, that’s a fairly big thing.” Her world revolved around quantum gravity. Shortly after separating from Smolin, she had fallen into a relationship with a German postdoctoral fellow at the institute, Olaf Dreyer, whom she married after four years. They lived and breathed their discipline. “It’s nice to share these things with somebody closely,” she says.

    But Markopoulou found her more radical theories were sometimes greeted with the sly criticism that they were “creative.” “The fact that you don’t look like the standard makes it hard for them; they will take longer to form judgments, which means you stay in the doubt area for longer,” she says. It was made worse by the pervasive attitude among physicists that you should gather your laurels by doing sensible calculations throughout your career, and only cook up new theories of quantum gravity in your old age.

    Markopoulou refused to play that game, and a sense of discontent began to build. Every problem she solved created a quagmire of fresh ones; and, daughter of sculptors, she was tiring of academic papers as the only tangible thing she could “make.” After a while, even her public-facing activities began to grate. “There is a part of me that felt like a kind of clown, telling people magical things about the universe,” she says. “Something you take very seriously and you’ve devoted your life to, and you’ve made your own sacrifices for, is, for other people, at best entertainment.” She consoled herself with something Isham once told her, counsel he’d received in turn from the physicist John Archibald Wheeler. When it comes to quantum gravity, he says, you’re bound to fail. “What’s important is not the fact you fail, but how you fail.” Markopoulou was determined to fail better, to borrow Samuel Beckett’s phrase.

    In 2008, the South African physicist Turok was appointed director of Perimeter. Turok, who describes himself as “very demanding,” pulled back from the more outré flavors of foundational physics and expanded into other areas, including particle physics, cosmology, and quantum computing. He didn’t want the institute, he says, “to be center for alternative physicists who were doing unusual things in speculative directions.”

    By 2009, Markopoulou’s personal life was undergoing its own quantum transitions. At a conference in Waterloo about physics and the financial crisis, organized by Smolin, Markopoulou met systems theorist and physicist Doyne Farmer. The pair was instantly dazzled by one another, and within five days decided to upend their lives to be together. Markopoulou separated from Dreyer and Farmer from his wife. Not long after, she got pregnant on a road trip from San Francisco to Santa Fe in Farmer’s 1967 Datsun convertible. Their son, Maris, was born in 2010; a year later, Markopoulou’s mother Maria passed away.

    Markopoulou was still attracted to deep inquiry, but the further down she went, the less objective she found her colleagues’ judgments about the value of her work. “If you’re in a place where everything is certain, that’s a very boring place,” she says. “But if you jump out with no parachute, it’s either a sociological exercise or a folly.” She’d been striving to position her research at the metaphorical “edge of chaos,” the point at which order emerges from complexity. But she’d started to get the creeping suspicion she was back with the artists in her mothers’ studio, competing for recognition and influence without any clear standards.

    “In the absence of any kind of experimental confirmation or the ability to falsify your theories, quantum gravity has ended up being dominated by a few influential tastemakers,” says Lloyd. “Fotini fell foul of that because she had her own strong sense of what is a good thing to do; her tastes were different.”

    As the institute continued to grow, Turok faced the challenges of needing to formalize its processes and manage larger numbers of physicists. Perimeter had already begun the process of implementing tenure for its faculty, which Turok inherited. Markopoulou prepared to apply. By this time she was back in Berlin again, on a fellowship at the Max Planck Institute. She put together a dossier of her accomplishments for Turok, which was also to be reviewed by a tenure committee and quantum gravity experts.

    Turok says he respected Markopoulou, but doubted her work would lead anywhere. He denied her tenure. “Fotini had pursued a very independent line of inquiry that was really very different and hardly acknowledged by leading researchers in the field,” Turok says. “I applauded her for her bravery for pursuing her own line, but that inevitably brings risks with it. She is a very fundamental thinker; she had original ideas. But at the end of the day you had to decide if those ideas are going to pan out.”

    Markopoulou says she was disappointed that Perimeter had “shifted from a flat hierarchy of scientists to an all-powerful director.” Turok emailed her out of the blue, she says, to stop the review process and deny her tenure. “As a result of my case, an independent consultant was appointed because I had been the only woman faculty for nine years, I had a strong academic record, and Neil stopped the tenure process just as I had a baby,” Markopoulou says. (“I respectfully beg to differ,” Turok responds. “A tenure review process was never initiated.”) The matter is subject to an out-of-court settlement.

    In the autumn of 2011, Markopoulou walked out of Perimeter for good.

    One sunny morning in March, I visit Markopoulou at her home outside Oxford, perched on a hill and encircled by stands of oak, ash, and silvery birch. Nancy, the wife of the poet and classicist Robert Graves, used to run a grocery store on the site before the poet John Masefield knocked it down to build a theater in 1924. The top rooms sit snug under the original proscenium arch. Markopoulou loves theater—a legacy of being Greek, she says. It allows you to “step out of your normal shoes, to shift reality a bit, and to actively participate by forcing you to suspend your belief.” Not unlike science at its highest levels.

    In the living room, Markopoulou bundles herself up into a burgundy armchair with the cheerful self-possession of a family cat. A Persian rug sprawls across the wood floor, monopolized by a Lego space station. One of her mother’s bronze busts broods from a windowsill, a beautiful, dauby figure of a woman with braids parted down the middle. “You were asking me the other day what made me change,” she says. “One big thing was my mother died and opened up a space for me.” Markopoulou wouldn’t have touched art while her mother was alive, but recognizes now that a similar desire to make, to craft and to create, is part of who she is.

    “In many ways, physics and what I did are almost ideally positioned to my experience with my mother,” she says. “I probably did come out of that wanting a much more firm grasp of what is what, and objective decision-making. Now I don’t feel I need that much any more, but growing up that was a big deal. Also, it was far away from her, it was my own space, but at the same time there were many ways in which the deeper challenges are the same.” Sculpture is a lot like creating a physics theory, she says, because you have to turn it around and make sure it works from every angle. “You have to understand the essence of what you’re doing before you start, because only then do you have a chance that it’s going to work from all sides.”

    Did she believe this philosophy could help her solve quantum gravity? “I never really wanted to single-handedly solve it. But I never went in thinking that we can’t. I always assumed it was possible.” Does she still think it is? “Not soon, but I don’t know. If I knew, I would be doing it,” she quips.

    During her unsteady transition out of physics, Farmer was a pillar of support for Markopoulou. “I’m very much what I do, so going through a transition is a time when I don’t know who I am,” she says. “I was lucky to have the context where that was perfectly possible.”

    Farmer is a distinguished and idiosyncratic physicist in his own right. While still in grad school at the University of California, Santa Cruz, studying physical cosmology, he and fellow physicist, Norman Packard, created one of the world’s first wearable computers. Released in the 1970s, it was a toe-operated device embedded in the tip of a shoe, which allowed the wearer and an accomplice to track the progress of a roulette ball and achieve a 20 percent advantage over the house. He and Packard later decided to found one of the first predictive stock trading companies, which was ultimately sold to UBS, a financial services company, in 2006. Farmer’s interests now lie in “econophysics,” a field which he founded and which applies the mathematics of natural systems to gather insights about the economy.

    When Farmer landed a post at Oxford University in 2011, Markopoulou was faced with “the usual two body problem in academia” of trying to find a job nearby. But when she started looking, she realized her heart wasn’t in it. She had been toying with industrial design, and asked the advice of the musician Brian Eno, a physics follower and a friend. He advised her to look into the master’s program in Innovation Design Engineering run by the Royal College of Arts and Imperial College in London, and wrote her a letter of reference.

    She sailed through the admissions process, which included an exercise where prospective students had to explain how they would evade a pack of zombies chasing them toward the lip of a cliff. She enjoyed the classwork but found the mental shift hard at first. “It just felt silly because you go from, ‘This is how the universe started’ to, ‘This mattress has these bubbles.’ ”

    But she loved making things, and also made the personal connections that evolved into Doppel. A sailing trip to Greece, in which the Doppel crew nearly scuppered Markopoulou’s and Farmer’s large-bottomed boat on the rocks off the island of Cephalonia, cemented the team’s conviction that they could withstand the trials of doing a start-up.

    The kernel for Doppel came from a piece in New Scientist about interoception—the way humans can discern the internal states of the body and conceive of it as “their own.” The idea is that our sense of self is not merely a mental process that somehow envelops the body, but somehow arises from the two-way conversation between the brain and other organs. As Manos Tsakiris, the softly spoken psychologist and neuroscientist who advises Doppel, tells me, “You cannot cut off cognition from the rest of the body, and you cannot cut off the body from the rest of the world in which you interact.” By harvesting your natural response to rhythm, Doppel runs counter to the notion that the self resides in the mind alone—that the human is a creature of the will, a maker of rational decisions, a sovereign mind bossing around dumb matter.

    With hindsight, Markopoulou sees her work at Doppel as a “natural evolution” from what she did before. Isham had inspired her to pursue physics as a quest to understand reality from within, when scientists can’t stand apart from what they’re trying to analyze. But now, instead of the universe as the ultimate system, she has the human body. “If you think about physics, it’s a human creation. The equations represent stuff we come up with because of our senses. So shouldn’t our senses be part of what goes into physics?” Markopoulou says.

    Markopoulou thinks that many disputes in science come down to competing metaphysical commitments. She recognizes that her own belief in the fundamental nature of time, and her dislike of timelessness, is a moral preference as much as anything else. “Most of the physics where time does not exist comes with determinism as well. There is something about thinking that time is real and being responsible for your actions,” she tells me.

    This belief in the inexorable movement of time is what seems to have allowed Markopoulou to reinvent herself—to turn away from years spent building a career as a physicist and to start from scratch as a designer and entrepreneur. “This is the nice thing about me, but it’s also a little bit weird: When I do something, I just do it. So when I switched, I switched,” she says. “Our mind can live in the past, the future, or any fantasy place it wants, but our body only processes the now.”

    Doppel is unlikely to be the end of Markopoulou’s journey. “Whatever it is that you do, it has to have a context. Academia is one context, business is another context. I can’t really tell you if it’s better or worse, it’s a different set of rules—and right now I have come to no conclusions as to what I think about those rules. I’m still exploring.”

    See the full article here .

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    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

  • richardmitnick 6:59 am on April 23, 2017 Permalink | Reply
    Tags: , , Basic Research, , , Singularity   

    From Science Alert: “Physicists Say They’ve Found a Way to Detect Naked Singularities… if They Exist” 


    Science Alert

    21 APR 2017


    Black holes are weird: insanely dense objects that are crammed into such a small space they cause space-time to distort and the laws of physics to break down into a singularity.

    Fortunately, the Universe shields us from this weirdness by wrapping black holes in event horizons. But now, physicists say they’ve found a way we could detect something even more extreme – a naked singularity – and most likely bend the laws of physics in the process.

    “A naked singularity, if such a thing exists, would be an abrupt hole in the fabric of reality – one that would not just distort space-time, but would also wreak havoc on the laws of physics wherever it goes and lead to a catastrophic loss of predictability,” explains Avaneesh Pandey for IB Times.

    If that sounds a little too confronting, don’t worry, this whole study is purely theoretical, and is hinged on one very big assumption – that naked singularities actually exist in our Universe, something that scientists have never confirmed.

    But according to Einstein’s theory of general relativity at least, and our best computer models to date, naked singularities are possible.

    So, what are they? A singularity can form when huge stars collapse at the end of their lives into regions so small and dense, physics as we know it fails to explain what could happen there.

    There are two general laws of physics that govern our understanding of reality: quantum mechanics, which explains all the small stuff, such as the behaviour of subatomic particles; and general relativity, which describes the stuff we can see, such as stars and galaxies.

    When applied to singularities, both these schools of thought predict different and incompatible outcomes.

    And we’ve never really had to deal with that conundrum, because all the singularities we know of are inside black holes, wrapped in an event horizon from which not even light can escape – or at the very birth of our Universe, shrouded by radiation we can’t see past. Out of sight, out of mind, right?

    But naked singularities are theoretical singularities that are exposed to the rest of the Universe for some reason.

    Below you can see an illustration of a black hole wrapped in its event horizon (dotted line) on the left, and a naked singularity on the right. The arrows indicate light, which would be able to escape a naked singularity, but not a black hole.

    Sudip Bhattacharyya/Pankaj Joshi

    Assuming they do exist, the big question then is how would we be able to distinguish a naked singularity from a regular black hole, and this is where the new study comes in.

    Researchers from the Tata Institute of Fundamental Research in India have come up with a two-step plan based on the fact that singularities, as far as we know, are rotating objects, just like black holes.

    According to Einstein’s theory of general relativity, the fabric of space-time in the vicinity of any rotating objects gets ‘twisted’ due to this rotation. And this effect causes a gyroscopic spin and makes the orbits of particles around the rotating objects ‘precess’, or change their rotational axis.

    You can watch the hypnotic precession of a gyroscope below to see what we mean – its axis is no longer straight:


    Based on this, the researchers say that we could figure out the nature of a rotating objects by measuring the rate at which a gyroscope precesses – its precession frequency – at two fixed points close to the object.

    According to the new paper, there are two possibilities:

    1. The precession frequency of the gyroscope changes wildly between the two points, which suggests the rotating object in question is a regular black hole.
    2. The precession frequency changes in a regular, well-behaved manner, indicating a naked singularity.

    Obviously getting a gyroscope close enough to a black hole to perform these experiments isn’t exactly easy.

    But that’s okay, because the team has also come up with a way to observe the same effect from here on Earth – measuring the precession frequencies of matter falling into either black holes or naked singularities using X-ray wavelengths.

    “This is because the orbital plane precession frequency increases as the matter approaches a rotating black hole, but this frequency can decrease and even become zero for a rotating naked singularity,” the team’s press release explains.

    Again, we have to make it clear that all of this is wildly speculative at this time – we have never found any candidate naked singularities, and we’re only just beginning to truly understand regular black holes.

    It’s also worth noting that last week, another team of researchers suggested that even if naked singluarities exist, strange quantum effects could keep them hidden from us.

    So there’s definitely no consensus right now on whether we’ll ever get the chance to study naked singularities.

    And that’s not a terrible thing for now, because are we really ready to observe what goes on at the edge of our Universe?

    Maybe, in our lifetime, we’ll find out.

    The research has been published in Physical Review D.

    See the full article here .

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  • richardmitnick 1:23 pm on April 22, 2017 Permalink | Reply
    Tags: , , , Basic Research,   

    From AGU: “New study ranks hazardous asteroid effects from least to most destructive” 

    AGU bloc

    American Geophysical Union

    19 April 2017
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    The trace left in the sky by the meteor that broke up over Chelyabinsk, Russia, in 2013. A new study explored seven effects associated with asteroid impacts — heat, pressure shock waves, flying debris, tsunamis, wind blasts, seismic shaking and cratering — and estimated their lethality for varying sizes.
    Credit: Alex Alishevskikh

    Violent winds, shock waves from impacts pose greatest threat to humans.

    If an asteroid struck Earth, which of its effects—scorching heat, flying debris, towering tsunamis—would claim the most lives? A new study has the answer: violent winds and shock waves are the most dangerous effects produced by Earth-impacting asteroids.

    The study explored seven effects associated with asteroid impacts—heat, pressure shock waves, flying debris, tsunamis, wind blasts, seismic shaking and cratering—and estimated their lethality for varying sizes. The researchers then ranked the effects from most to least deadly, or how many lives were lost to each effect.

    Overall, wind blasts and shock waves were likely to claim the most casualties, according to the study. In experimental scenarios, these two effects accounted for more than 60 percent of lives lost. Shock waves arise from a spike in atmospheric pressure and can rupture internal organs, while wind blasts carry enough power to hurl human bodies and flatten forests.

    “This is the first study that looks at all seven impact effects generated by hazardous asteroids and estimates which are, in terms of human loss, most severe,” said Clemens Rumpf, a senior research assistant at the University of Southampton in the United Kingdom, and lead author of the new study published in Geophysical Research Letters, a journal of the American Geophysical Union.

    Rumpf said his findings, which he plans to present at the 2017 International Academy of Astronautics Planetary Defense Conference in Tokyo, Japan, could help hazard mitigation groups better prepare for asteroid threats because it details which impact effects are most dominant, which are less severe and where resources should be allocated.

    Though studies like his are necessary to reduce harm, deadly asteroid impacts are still rare, Rumpf said. Earth is struck by an asteroid 60 meters (more than 190 feet) wide approximately once every 1500 years, whereas an asteroid 400 meters (more than 1,300 feet) across is likely to strike the planet every 100,000 years, according to Rumpf.

    “The likelihood of an asteroid impact is really low,” said Rumpf. “But the consequences can be unimaginable.”

    Modeling asteroid effects

    Rumpf and his colleagues used models to pepper the globe with 50,000 artificial asteroids ranging from 15 to 400 meters (49 to 1312 feet) across—the diameter range of asteroids that most frequently strike the Earth. The researchers then estimated how many lives would be lost to each of the seven effects.

    Land-based impacts were, on average, an order of magnitude more dangerous than asteroids that landed in oceans.

    Large, ocean-impacting asteroids could generate enough power to trigger a tsunami, but the wave’s energy would likely dissipate as it traveled and eventually break when it met a continental shelf. Even if a tsunami were to reach coastal communities, far fewer people would die than if the same asteroid struck land, Rumpf said. Overall, tsunamis accounted for 20 percent of lives lost, according to the study.

    The heat generated by an asteroid accounted for nearly 30 percent of lives lost, according to the study. Affected populations could likely avoid harm by hiding in basements and other underground structures, Rumpf said.

    Seismic shaking was of least concern, as it accounted for only 0.17 percent of casualties, according to the study. Cratering and airborne debris were similarly less concerning, both garnering fewer than 1 percent of deaths.

    Only asteroids that spanned at least 18 meters (nearly 60 feet) in diameter were lethal. Many asteroids on the lower end of this spectrum disintegrate in Earth’s atmosphere before reaching the planet’s surface, but they strike more frequently than larger asteroids and generate enough heat and explosive energy to deal damage. For example, the meteor involved in the 2013 impact in Chelyabinsk, Russia, was 17 to 20 meters (roughly 55 to 65 feet) across and caused more than 1,000 injuries, inflicting burns and temporary blindness on people nearby.

    Understanding risk

    This chart shows reported fireball events for which geographic location data are provided. Each event’s calculated total impact energy is indicated by its relative size and by a color.
    Credit: NASA

    “This report is a reasonable step forward in trying to understand and come to grips with the hazards posed by asteroids and comet impactors,” said geophysicist Jay Melosh, a distinguished professor in the Department of Earth, Atmospheric and Planetary Sciences at Purdue University in Lafayette, Indiana.

    Melosh, who wasn’t involved in the study, added that the findings “lead one to appreciate the role of air blasts in asteroid impacts as we saw in Chelyabinsk.” The majority of the injuries in the Chelyabinsk impact were caused by broken glass sent flying into the faces of unknowing locals peering through their windows after the meteor’s bright flash, he noted.

    The study’s findings could help mitigate loss of human life, according to Rumpf. Small towns facing the impact of an asteroid 30 meters across (about 98 feet) may fare best by evacuating. However, an asteroid 200 meters wide (more than 650 feet) headed for a densely-populated city poses a greater risk and could warrant a more involved response, he said.

    “If only 10 people are affected, then maybe it’s better to evacuate the area,” Rumpf said. “But if 1,000,000 people are affected, it may be worthwhile to mount a deflection mission and push the asteroid out of the way.”

    See the full post here .

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    The purpose of the American Geophysical Union is to promote discovery in Earth and space science for the benefit of humanity.

    To achieve this mission, AGU identified the following core values and behaviors.

    Core Principles

    As an organization, AGU holds a set of guiding core values:

    The scientific method
    The generation and dissemination of scientific knowledge
    Open exchange of ideas and information
    Diversity of backgrounds, scientific ideas and approaches
    Benefit of science for a sustainable future
    International and interdisciplinary cooperation
    Equality and inclusiveness
    An active role in educating and nurturing the next generation of scientists
    An engaged membership
    Unselfish cooperation in research
    Excellence and integrity in everything we do

    When we are at our best as an organization, we embody these values in our behavior as follows:

    We advance Earth and space science by catalyzing and supporting the efforts of individual scientists within and outside the membership.
    As a learned society, we serve the public good by fostering quality in the Earth and space science and by publishing the results of research.
    We welcome all in academic, government, industry and other venues who share our interests in understanding the Earth, planets and their space environment, or who seek to apply this knowledge to solving problems facing society.
    Our scientific mission transcends national boundaries.
    Individual scientists worldwide are equals in all AGU activities.
    Cooperative activities with partner societies of all sizes worldwide enhance the resources of all, increase the visibility of Earth and space science, and serve individual scientists, students, and the public.
    We are our members.
    Dedicated volunteers represent an essential ingredient of every program.
    AGU staff work flexibly and responsively in partnership with volunteers to achieve our goals and objectives.

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