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  • richardmitnick 2:47 pm on May 27, 2016 Permalink | Reply
    Tags: , Astronomy, , Mysterious Changes in the Bright Spots on Ceres   

    From Astro Watch: “Life on Ceres? Mysterious Changes in the Bright Spots Still Baffle Scientists” 

    Astro Watch bloc

    Astro Watch

    May 26, 2016

    1
    No image caption. No image credit.

    Bright spots on the dwarf planet Ceres continue to puzzle researchers. When recently a team of astronomers led by Paolo Molaro of the Trieste Astronomical Observatory in Italy, conducted observations of these features, they found out something unexpected. The scientists were surprised to detect that the spots brighten during the day and also show other variations. This variability still remains a mystery.

    The bright features have been discovered by NASA’s Dawn spacecraft which is orbiting this dwarf planet, constantly delivering substantial information about it.

    NASA/Dawn Spacescraft
    NASA/Dawn Spacescraft

    These spots reflect far more light than their much darker surroundings. The composition of these features is discussed as the scientists debate if they are made of water ice, of evaporated salts, or something else.

    Molaro and his colleagues studied the spots on Ceres in July and August 2015, using the High Accuracy Radial velocity Planet Searcher (HARPS), as was reported by the European Southern Observatory (ESO) earlier this year.

    ESO/HARPS
    ESO 3.6m telescope & HARPS at LaSilla
    ESO 3.6m telescope & HARPS at LaSilla

    This instrument, mounted on ESO’s 3.6m telescope at La Silla Observatory in Chile, enables measurements of radial velocities with the highest accuracy currently available.

    ESO 3.6 meter telescope interior
    ESO 3.6 meter telescope at LaSilla interior

    By utilizing HARPS, the researchers found out unexpected changes in the mysterious bright spots. However, at the beginning they thought that it was an instrumental problem. But after double checking, they had to conclude that the radial velocity anomalies were likely real. Then the team noticed that they were connected to periods of time when the bright spots in the Occator crater were visible from the Earth. So the scientists made an association between them.

    However, these detected variations still continue to perplex the astronomers as they haven’t found a plausible explanation for their occurrence.

    “We know nothing about these changes, really. And this increases the mystery of these spots,” Molaro told Astrowatch.net.

    One of the proposed hypotheses is that the observed changes could be triggered by the presence of volatile substances that evaporate due to solar radiation. When the spots are on the side illuminated by the sun they form plumes that reflect sunlight very effectively. The scientists suggest that these plumes then evaporate quickly, lose reflectivity and produce the observed changes.

    “It is already well known that a lot of water hides beneath the surface of Ceres, so water ice or clathrates hydrates are the most natural hypotheses. But a proper answer will be hopefully provided by scientists working in the Dawn team in the coming months,” Molaro said.

    He noted that the indication of variability needs to be confirmed by direct imaging of Occator’s bright spot at the highest available spatial resolution.

    “This kind of measurements are underway. I would say that the detection of a variability improves our ignorance rather than our understanding of this planetary body,” Molaro revealed.

    The team is currently applying for further observations by the end of this year to repeat in a more systematical way what they have done in their pilot project. An important aspect of their work is to have shown a new way to study Ceres from ground, which could turn out to be useful even after the end of the Dawn mission. However by now, they are eager to see the results from the Dawn spacecraft in the next months.

    If the team’s theory is confirmed, Ceres would seem to be internally active. While this dwarf planet is known to be rich in water, it is unclear whether this is related to the bright spots. It is also still debated if Ceres due to its vast reservoir of water, could be a suitable place to host microbial life.

    “Life as we know it on Earth needs liquid water, biogenic elements and a stable source of energy. Is Ceres a good place to have these things simultaneously and for a substantial amount of time, like billions of years? Nobody knows at the moment,” Molaro concluded.

    See the full article here .

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  • richardmitnick 11:38 am on May 27, 2016 Permalink | Reply
    Tags: , Astronomy, , Leon Golub Lead Editor for the Sun and Heliosphere corridor   

    From AAS NOVA: “AAS Publishing News: An Interview with Leon Golub” 

    AASNOVA

    Amercan Astronomical Society

    27 May 2016
    Susanna Kohler

    1
    Leon Golub, Harvard Smithsonian Center for Astrophysics, Massachusetts, USA, is the new Lead Editor for the Sun and Heliosphere corridor.

    In the lead-up to next week’s 2016 Solar Physics Division (SPD) meeting, we wanted to introduce you to Leon Golub, our new Lead Editor for the Sun and the Heliosphere corridor.

    Leon is a Senior Astrophysicist in the High Energy Division at the Harvard-Smithsonian Center for Astrophysics. He specializes in studies of solar and stellar magnetic activity, and he has built numerous rocket and satellite instruments to study the Sun and its dynamic behavior.

    Tell me about your field of research and some of your current projects.

    I’ve been working primarily on understanding the dynamics of the solar corona, especially using new types of instrumentation that can provide challenges to our theoretical understanding.

    Why did you choose this field?

    Shortly after graduating from MIT in experimental high energy physics I found a position with a group that was preparing to launch an X-ray telescope on Skylab as part of the cluster of solar instruments called the Apollo Telescope Mount. I have stayed with that field and related ones ever since.

    What do you consider to be some of the biggest open questions in solar and heliospheric research today?

    There are so many major questions that it’s difficult to just settle on a few. The heliosphere is defined by the extent of the influence of the Sun on the interstellar medium.

    3
    Heliosphere from http://www.nasa.gov/centers/ames/news/releases/2001/01images/Pioneer10/pioneer10.htm

    It is an exciting time in that area of study, because we now have the ability to make impressive new observations that allow us to test our understanding of that outer boundary.

    Within those limits, the Sun has a major influence on solar system objects via its gravitational pull, its light and heat, and the magnetized plasma and high energy particles that it emits in all directions. We are making major discoveries related to how the Sun has influenced the formation and evolution of the planets, including our own planet.

    The source of all this influence is, of course, the Sun itself, and we are working to understand how magnetic fields are generated inside the Sun and how they produce the observed dynamic processes once they emerge from inside.

    4
    A coronal mass ejection observed by the LASCO C3 instrument on the Solar and Heliospheric Observatory. [NASA/ESA/SOHO]

    ESA/SOHO
    ESA/SOHO

    What do you anticipate will be some of the most exciting topics presented on at the SPD meeting next week?

    We have some new and exciting presentations that I’m looking forward to, related to solar magnetism and solar dynamics, especially flares and mass ejections. There are also some spectacular developments going on in improving the quality of ground-based observations, normally limited by the murkiness of our atmosphere. I expect to see some thrilling new observations from them.

    What do you do in your work for ApJ?

    I am one of the new Lead Editors, heading the Solar and Heliospheric corridor. This is a new level of editorial work situated between the Editor in Chief and the Scientific Editors (SEs). I am also acting as an SE myself, along with the other Solar and Heliospheric SEs.

    What do you think makes for a well-authored paper?

    I have long thought that a training in journalism is the best preparation for authoring scientific papers. What is your headline? Can you inform the reader succinctly and clearly?

    Is there anything else you’d like to share about the publishing process with potential authors?

    I would tell potential authors that our primary goal is to help them publish high quality work, and that the review process is critical to that effort. It takes time, but it makes all the difference.

    See the full article here .

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  • richardmitnick 11:14 am on May 27, 2016 Permalink | Reply
    Tags: Astronomy, , , , NASA's Juno Spacecraft Crosses Jupiter/Sun Gravitational Boundary   

    From JPL-Caltech: “NASA’s Juno Spacecraft Crosses Jupiter/Sun Gravitational Boundary” 

    NASA JPL Banner

    JPL-Caltech

    May 27, 2016
    DC Agle
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-9011
    agle@jpl.nasa.gov

    NASA /Juno
    NASA /Juno

    Since its launch five years ago, there have been three forces tugging at NASA’s Juno spacecraft as it speeds through the solar system. The sun, Earth and Jupiter have all been influential — a gravitational trifecta of sorts. At times, Earth was close enough to be the frontrunner. More recently, the sun has had the most clout when it comes to Juno’s trajectory. Today, it can be reported that Jupiter is now in the gravitational driver’s seat, and the basketball court-sized spacecraft is not looking back.

    “Today the gravitational influence of Jupiter is neck and neck with that of the sun,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “As of tomorrow, and for the rest of the mission, we project Jupiter’s gravity will dominate as the trajectory-perturbing effects by other celestial bodies are reduced to insignificant roles.”

    Juno was launched on Aug. 5, 2011. On July 4 of this year, it will perform a Jupiter orbit insertion maneuver — a 35-minute burn of its main engine, which will impart a mean change in velocity of 1,212 mph (542 meters per second) on the spacecraft. Once in orbit, the spacecraft will circle the Jovian world 37 times, skimming to within 3,100 miles (5,000 kilometers) above the planet’s cloud tops. During the flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.

    Juno’s name comes from Greek and Roman mythology. The mythical god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife — the goddess Juno — was able to peer through the clouds and reveal Jupiter’s true nature.

    NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for NASA’s Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. The California Institute of Technology in Pasadena manages JPL for NASA.

    For more information about Juno visit these sites:

    http://www.nasa.gov/juno

    http://missionjuno.swri.edu

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 11:05 am on May 27, 2016 Permalink | Reply
    Tags: Astronomy, , , , , Object 1994 JR1   

    From Astronomy: “New Horizons collects first science on a Kuiper Belt object past Pluto” 

    Astronomy magazine

    Astronomy Magazine

    May 18, 2016
    NASA

    The spacecraft has now twice observed 1994 JR1, a Kuiper Belt object orbiting more than 3 billion miles from the Sun.

    NASA/New Horizons spacecraft
    NASA/New Horizons spacecraft

    1
    New Horizons scientists used light curve data – the variations in the brightness of light reflected from the object’s surface – to determine JR1’s rotation period of 5.4 hours. NASA/JHUAPL/SwRI

    Warming up for a possible extended mission as it speeds through deep space, NASA’s New Horizons spacecraft has now twice observed 1994 JR1, a 90-mile-wide (145 kilometers) Kuiper Belt object (KBO) orbiting more than 3 billion miles (5 billion km) from the Sun. Science team members have used these observations to reveal new facts about this distant remnant of the early solar system.

    Kuiper Belt. Minor Planet Center
    Kuiper Belt. Minor Planet Center

    Taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI) on April 7-8 from a distance of about 69 million miles (111 million km), the images follow on observations from November 2015, when New Horizons detected JR1 from 170 million miles (280 million km) away.

    NASA New Horizons LORRI Camera
    NASA New Horizons LORRI Camera

    Simon Porter, a New Horizons science team member from the Southwest Research Institute (SwRI) in Boulder, Colorado, said the observations contain several valuable findings. “Combining the November 2015 and April 2016 observations allows us to pinpoint the location of JR1 to within 600 miles (1,000km), far better than any small KBO,” he said, adding that the more accurate orbit also allows the science team to dispel a theory, suggested several years ago, that JR1 is a quasi-satellite of Pluto.

    From the closer vantage point of the April 2016 observations, the team also determined the object’s rotation period, observing the changes in light reflected from JR1’s surface to determine that it rotates once every 5.4 hours (or a JR1 day). “That’s relatively fast for a KBO,” said John Spencer from SwRI. “This is all part of the excitement of exploring new places and seeing things never seen before.”

    Spencer added that these observations are great practice for possible close-up looks at about 20 more ancient Kuiper Belt objects that may come in the next few years, should NASA approve an extended mission. New Horizons flew through the Pluto system on July 14, 2015, making the first close-up observations of Pluto and its family of five moons. The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, 2014 MU69, on January 1, 2019.

    See the full article here .

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  • richardmitnick 8:44 am on May 27, 2016 Permalink | Reply
    Tags: Astronomy, , Kepler-62f, ,   

    From UCLA: “A planet 1,200 light-years away is a good prospect for a habitable world” – Women in Science 

    UCLA bloc

    UCLA

    May 26, 2016
    Stuart Wolpert

    1
    Kepler-62f, shown here in an artist’s rendering, is far enough from its star that its atmosphere would need a high concentration of carbon dioxide to maintain liquid water on the planet’s surface. Artist’s conception by NASA Ames/JPL-Caltech/T. Pyle

    A distant planet known as Kepler-62f could be habitable, a team of astronomers reports.

    The planet, which is about 1,200 light-years from Earth in the direction of the constellation Lyra, is approximately 40 percent larger than Earth. At that size, Kepler-62f is within the range of planets that are likely to be rocky and possibly could have oceans, said Aomawa Shields, the study’s lead author and a National Science Foundation astronomy and astrophysics postdoctoral fellow in UCLA’s department of physics and astronomy.

    2
    Aomawa Shields. Martin Cox

    NASA’s Kepler mission discovered the planetary system that includes Kepler-62f in 2013, and it identified Kepler-62f as the outermost of five planets orbiting a star that is smaller and cooler than the sun.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    But the mission didn’t produce information about Kepler-62f’s composition or atmosphere or the shape of its orbit.

    Shields collaborated on the study with astronomers Rory Barnes, Eric Agol, Benjamin Charnay, Cecilia Bitz and Victoria Meadows, all of the University of Washington, where Shields earned her doctorate. To determine whether the planet could sustain life, the team came up with possible scenarios about what its atmosphere might be like and what the shape of its orbit might be.

    “We found there are multiple atmospheric compositions that allow it to be warm enough to have surface liquid water,” said Shields, a University of California President’s Postdoctoral Program Fellow. “This makes it a strong candidate for a habitable planet.”

    On Earth, carbon dioxide makes up 0.04 percent of the atmosphere. Because Kepler-62f is much farther away from its star than Earth is from the sun, it would need to have dramatically more carbon dioxide to be warm enough to maintain liquid water on its surface, and to keep from freezing.

    The team ran computer simulations based on Kepler-62f having:

    An atmosphere that ranges in thickness from the same as Earth’s all the way up to 12 times thicker than our planet’s.
    Various concentrations of carbon dioxide in its atmosphere, ranging from the same amount as is in the Earth’s atmosphere up to 2,500 times that level.
    Several different possible configurations for its orbital path.

    They found many scenarios that allow it to be habitable, assuming different amounts of carbon dioxide in its atmosphere.

    Shields said that for the planet to be consistently habitable throughout its entire year, it would require an atmosphere that is three to five times thicker than Earth’s and composed entirely of carbon dioxide. (This would be analogous to replacing every molecule in Earth’s atmosphere with carbon dioxide, which means that the planet would have 2,500 times more carbon dioxide in its atmosphere.) Having such a high concentration of carbon dioxide would be possible for the planet because, given how far it is from its star, the gas could build up in the planet’s atmosphere as temperatures get colder to keep the planet warm.

    “But if it doesn’t have a mechanism to generate lots of carbon dioxide in its atmosphere to keep temperatures warm, and all it had was an Earth-like amount of carbon dioxide, certain orbital configurations could allow Kepler-62f’s surface temperatures to temporarily get above freezing during a portion of its year,” she said. “And this might help melt ice sheets formed at other times in the planet’s orbit.”

    The research is published online in the journal Astrobiology, and will be in a future print edition.

    The scientists made their calculations of the shape of the planet’s possible orbital path using an existing computer model called HNBody, and they used existing global climate models (the Community Climate System Model and the Laboratoire de Me´te´orologie Dynamique Generic model) to simulate its climate. It was the first time astronomers have combined results from these two different types of models to study an exoplanet, the term for a planet outside our solar system.

    Shields said the same technique could be applied to understand whether exoplanets much closer to Earth could be habitable, so long as the planets are likely to be rocky, Shields said. (Gas planets have very different compositions.)

    “This will help us understand how likely certain planets are to be habitable over a wide range of factors, for which we don’t yet have data from telescopes,” she said. “And it will allow us to generate a prioritized list of targets to follow up on more closely with the next generation of telescopes that can look for the atmospheric fingerprints of life on another world.”

    Scientists do not know whether life could exist on an exoplanet, but Shields is optimistic about finding life in the universe.

    More than 2,300 exoplanets have been confirmed, and a few thousand others are considered planet candidates, but only a couple dozen are known to be in the “habitable zone” — meaning that they orbit their star at a distance that could enable them to be warm enough to have liquid water on their surfaces, Shields said.

    Shields earned a master’s degree in acting from UCLA and worked as an actor. In January 2015, she founded Rising Stargirls, a program that teaches middle school-aged girls of color about astronomy and astrobiology using theater, writing and visual art. Teachers can request a free copy of the Rising Stargirls discussion guide and activity book through the program’s website.

    The Kepler space telescope is NASA’s first mission capable of detecting Earth-size planets around stars like our sun.

    See the full article here .

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    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 6:47 am on May 27, 2016 Permalink | Reply
    Tags: , Astronomy, , Breakthrough Starshot, , Yuri Milner   

    From AAAS: “Q&A: Web billionaire describes his plan to shoot for the stars” 

    AAAS

    AAAS

    May. 26, 2016
    Zeeya Merali

    1
    Breakthrough Starshot lasers. Breakthrough Starshot will require lasers many times more powerful than any existing today.
    Breakthrough Initiatives

    Last month, Russian internet billionaire Yuri Milner announced plans to send thousands of tiny spacecraft to visit Alpha Centauri, the closest star system at 4.4 light-years from Earth. Dubbed Breakthrough Starshot, the mission aims to take close-up images and collect data from any potentially habitable planets there.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker
    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    In order to cover the vast distance—41 trillion kilometers—in a reasonable time, the proposed spacecraft will each weigh less than a gram. Once in space, they will unfurl lightweight sails to catch laser beams shot from Earth, accelerating to one-fifth the speed of light under light pressure. Launch could be 30 years off, and the trip to Alpha Centauri would take a further 2 decades.

    Milner, who also supports the multimillion-dollar Breakthrough Prizes and Breakthrough Listen, a search for signs of extraterrestrial intelligence, has committed $100 million to this venture. But Breakthrough Starshot has polarized opinion: Some are enthused by its ambition, whereas others say it is costly and unnecessary, isn’t feasible, or is downright dangerous. Milner spoke with Science by phone about the challenges facing the project and how he answers his critics. His responses have been edited for clarity and brevity.

    Q: How did your interest in space travel and in this mission to Alpha Centauri come about?

    A: I was named Yuri after Yuri Gagarin because I was born the same year the Russian cosmonaut was launched on the first manned space flight. So I’ve carried this message about space travel in my name my whole life!

    Breakthrough Starshot came from a small working group we put together to devise a practical space project to a neighboring star system that could achieve results within the lifetime of a generation. They considered various propulsion mechanisms for interstellar travel—including fusion engines and matter-antimatter propulsion—and concluded that the sail configuration is the most feasible in a reasonable time frame.

    The idea of using spacecraft with solar-powered sails is actually very old, but until recently it was purely theoretical. Over the past 20 years there has been significant progress in microelectronics, nanomaterials, and laser technology that means we can now have a sensible conversation about making a gram-scale starship and accelerating it to 20% of the speed of light.

    2
    Starstruck: Yuri Milner. Breakthrough Initiatives

    Q: You’ve contributed $100 million dollars, but the final project could cost $10 billion. Where will this extra money come from?

    A: We’ve been open from day one that this is not something you can build in a garage and no one person can finance this machine. If this is going to happen, I envisage this as something that will need international collaboration on a financial scale comparable to CERN [the particle physics laboratory near Geneva, Switzerland].

    The seed money covers the first 5 to 10 years’ research and development phase, and within that time we should know if the challenges the project faces can be overcome or if they are insurmountable. The second phase will be to build a prototype and I think that can be financed by private investors, too. The final machine will need international backing.

    Q: Might the money be better spent on a new planet-hunting telescope?

    A: We’re actually in negotiations to spend some of the money to increase the capability of some ground-based telescopes to take a direct image of possible planets around Alpha Centauri. That would use existing infrastructure and we hope to announce it soon. This is important because we don’t even know with any degree of certainty if there are potentially habitable planets in the Alpha Centauri system to target with Breakthrough Starshot.

    But there is no substitute for a flyby and taking close-up images. This would be the equivalent of the New Horizons mission to Pluto.

    NASA/New Horizons spacecraft
    NASA/New Horizons spacecraft

    To get an equal quality image with a ground or near-Earth telescope, you would need a telescope on the scale of a few hundred kilometers and that’s not a small endeavor.

    Q: Even if the project’s giant lasers can be built, what about the damage they could potentially cause to the environment or their misuse as a weapon?

    A: Laser technology is following its own Moore’s law trajectory, so in a couple of decades’ time we think laser power will have increased sufficiently and such lasers will not be prohibitively expensive. But from the outset we identified that there must be some form of global consensus on its use. It may be that we have the technological capability but the project stalls because there is no agreement about the governance of such a machine.

    3
    The 4LGSF is part of the Adaptive Optics Facility on Unit Telescope 4 of the VLT.

    Q: Won’t laser beams fired through the atmosphere lose power through dispersion? Wouldn’t a space-based array be better?

    A: That would increase the cost 100 times and push the mission back a few hundred years. So for a space-based system, let’s just stop talking now. It’s not going to happen in our lifetime. A space-based laser also poses more serious policy issues because it could be pointed at Earth and is more difficult to control.

    The power from Earth-based lasers will not be dramatically different. The basic principle would be to utilize the adaptive optics already used by ground-based telescopes to deal with the challenges of the distortion of light passing through the atmosphere.

    Q: Critics have warned that the powerful laser beam could set the tiny craft spinning out of control or destroy the fragile sails. Have you considered such scenarios?

    A: Our experts have been looking into this and now think that a spinning craft may actually be more stable than a nonspinning one. But we don’t know whether the sails will melt when the laser hits them or what the craft will meet in interstellar space. We’ve identified more than 20 technological challenges to the successful completion of this project. More work is needed and that’s what the research phase is for.

    Q: Can you miniaturize the sensors, imaging, and signaling equipment to fit on such a small craft?

    A: We have carried out pretty detailed calculations that show we can shrink down the imaging equipment and sensors, even today. And surprisingly, to send a signal over trillions of miles you only need a small laser on board, powered by a watt-scale battery, and that can be made gram-scale. The sail would then be used as a dish to help transmit the signal, while the laser array on Earth would act as a receiver. So miniaturization of nanocraft is probably the least of the problems—the sails and the lasers are bigger obstacles.

    Q: Are you worried about sustaining a workforce for such a long-term project?

    A: It took two or three hundred years to build some cathedrals, but people did not lose interest. We have proven that we can focus on long term scientific projects, too: 2016 will be remembered as the year we detected gravitational waves but the LIGO experiment took 50 years; CERN is another example of experiments stretching over decades. This is the exciting next stage of space exploration being ignited and the fire will keep burning.

    Caltech/MIT Advanced aLigo detector in Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector in Livingston, LA, USA

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Q: You have identified many ways this project might fail. Are you worried that your investment might ultimately go to waste?

    A: Honestly, we are a very lucky generation because we are the first that could pull this off and, if we do, it will be incredible. But if not, we have promised to keep all the results of our research open to the public. One day our civilization will make use of it. It is human nature to explore the world around us and I don’t think that curiosity will ever go away.

    See the full article here .

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 5:45 pm on May 26, 2016 Permalink | Reply
    Tags: AIR & Space, Astronomy, , , , , , ,   

    From Air & Space: “SETI Gets an Upgrade” 

    1

    Air & Space

    June 2016
    Damond Benningfield

    2
    The Green Bank radio telescope in West Virginia may pull in an alien signal. (Jiuguang Wang)

    Dan Werthimer doesn’t mean to be rude, but he’s getting ready to eavesdrop on the neighbors.

    For decades, astronomers have been listening for messages sent to us—a “Hello, is anyone out there?” signal from intelligent aliens. But now Werthimer is about to get nosier; his team at the University of California at Berkeley is conducting the first search for communities on other worlds that are speaking to one another—between planets and even across star systems. And to do it, he has two of the world’s largest radio telescopes and support from a planet‑hunting optical telescope.

    Thanks to a new initiative announced last July, Werthimer’s team will begin searching for extraterrestrial civilizations, using instruments with greater sensitivity and scanning across a wider range of frequencies than any SETI (search for extraterrestrial intelligence) project to date. Called Breakthrough Listen, it began earlier this year and will continue for a decade at a price tag of $100 million. “It’s a lot of money, a lot of telescope time,” says Werthimer. “We’ll be able to look at a hundred billion radio channels simultaneously. A big problem in SETI is we don’t know on what frequency ET might be transmitting, so the more channels you can listen to, the better chance you have of finding” a communication.

    It’s an incredibly exciting time scientifically,” adds Werthimer’s colleague Andrew Siemion, director of Berkeley’s SETI Research Center and another Breakthrough Listen leader. “Something like one in five stars has an Earth-like planet…. And our ability to look for different kinds of signals from intelligent civilizations on those planets is growing by leaps and bounds.”

    3
    Andrew Siemion eyed the Green Bank Telescope, in the 13,000 square-mile National Radio Quiet Zone, as ideal for SETI research in 2010. (Dr. Andrew P.V. Siemion)

    Even with improvements in technology, though, SETI has remained a tiny area within the field of radio astronomy. “In the entire world, there are probably fewer than 12 people who do full-time SETI research,” according to Seth Shostak, a senior astronomer for the SETI Institute in nearby Mountain View.

    But that small cadre of researchers, with the help of a few dozen part-time SETI dabblers, has plowed through an impressive number of projects. They have scanned the skies at radio and optical wavelengths for intentional messages from other civilizations. Researchers have picked through data from NASA’s planet-hunting Kepler space telescope for evidence of vast architecture eclipsing part of a star’s light. (The public release of one star’s odd light curve last year generated a round of speculation about alien mega-structures. Sadly, followup observations have suggested that the more likely explanation is a swarm of comets.) And they’ve looked for super-civilizations producing copious amounts of waste heat in the form of infrared energy. And the ideas never stop coming: There is a proposal to search for alien probes and artifacts in the solar system (possible payoffs but expensive) and another to listen for signals in beams of neutrinos or the recently discovered gravitational waves (far beyond current technology).

    The bottleneck is never a lack of ideas,” says Shostak. “The problem has always been funding.”

    From the first search for extraterrestrial signals—Frank Drake’s Project Ozma in 1960—SETI has struggled to be taken seriously by traditional funding agencies. Modest NASA studies in the 1970s and 1980s were criticized by the U.S. Congress; in 1993, legislators axed what was meant to be NASA’s long-term sky survey after just a year. Since then the field has survived, barely, primarily on private funding sources.

    Then last summer, Russian billionaire Yuri Milner announced he would foot the bill for the biggest alien hunt in history. “In the 20th century, we stepped out from our planet—to space, to the moon, to the solar system,” Milner said at a press conference for Breakthrough Listen last summer. “In the 21st century, we will find out about life on a galactic scale…. It is time to open our eyes, our ears, and our minds to the cosmos.” Among the luminaries endorsing Milner’s project that day was astrophysicist Stephen Hawking.

    Milner, named after first-human-in-space Yuri Gagarin, was studying physics at Moscow University in the 1980s when the entrepreneurial spirit first hit him. He started buying American-made personal computers and reselling them in local shops, then ventured to the United States to get an MBA. After briefly working at the World Bank, he returned to Russia and began investing in businesses, parlaying the purchase of a small factory into the takeover of the country’s largest Internet company. With that move as an entry to the world of technology, Milner organized a venture capital fund, DST Global, which became an early investor in Facebook, then Twitter, Groupon, and Airbnb, along with major companies in India and China. According to Forbes, by the end of 2015 Milner amassed a net worth of $3.3 billion. In happy news for non-billionaire scientists, Milner started a foundation in 2012 that awards three $3 million prizes annually—the largest academic prize in the world—for achievements in fundamental physics, life sciences, and mathematics.

    He also refuses to give interviews about his latest investment, so we can get a sense of his intentions only from the people now running the Breakthrough Listen project. “He studied physics, he studied the same kind of books in school that I did, so he knows a lot about SETI,” says Werthimer. “He really appreciates all the subtle nuances, and he asks a lot of great questions. He knows the chances that we might find something are slim. But he speaks about this in the long term. He’s in it for the long haul.”

    4
    The Nickel Telescope at California’s Lick Observatory (with SETI’s Dan Werthimer, second from left) will look for lasers. Being used in the Niroseti project (Laurie Hatch)

    Werthimer was already in it for the long haul—he’s been working on SETI for decades, although his original love was the hardware, rather than the research. He’s been a tech junkie since his school days, when he joined the Homebrew Computer Club in California, where his fellow members included Apple founders Steve Jobs and Steve Wozniak. “We were kind of messing around in our basements, and we made the very first desktop,” Werthimer says. “Everybody in that club got filthy rich except for me, because I wanted to use the computers to do astronomy. But I got really good at computing. I built a lot of cool machines that were in some ways better than the Apple, but I never thought about selling them.”

    Werthimer began to build instruments that collect and analyze radio signals from space, and eventually started SETI@Home in 1999, a program that harnesses the background processing power of any computer it’s installed on to help sift through portions of the massive amounts of data from the Arecibo Observatory in Puerto Rico.

    SETI@home, BOINC project at UC Berkeley Space Science Lab
    SETI@home, BOINC project at UC Berkeley Space Science Lab

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA

    And although his work hasn’t revealed any alien civilizations, Werthimer isn’t bothered by the silence. “I wouldn’t be in this field if I were not an optimist,” he says. “We’ve covered maybe a billionth of the parameter space. We can rule out super-civilizations that want to conquer the galaxy”—whew—“but we can’t rule out civilizations like ours.”

    Siemion too developed an early interest in science and technology. “I did a report when I was in third grade on a book by Stephen Hawking, A Brief History of Time,” he says. “When I got to Berkeley I was looking over possible research opportunities, and I discovered that there was a SETI group. I had an ‘aha’ moment—I knew immediately that that’s what I would do.”

    Siemion led his first SETI project while he was still a graduate student. He got the idea in 2010, while he was attending a meeting at the Robert C. Byrd Green Bank Telescope in West Virginia to commemorate the 50th anniversary of Project Ozma. Attendees were re-creating Ozma, which originally used a small radio antenna at the Green Bank location, with the observatory’s new 300-foot-diameter Green Bank Telescope, the largest fully steerable radio telescope in the world. While Ozma took about 150 hours of telescope time, the re-creation required only a few seconds to scan the same amount of sky.

    “I started thinking: Why not do some real SETI with the telescope,” Siemion says. “On the plane back to San Francisco, I met in the aisle with a few other people, and we decided to write a proposal.” The idea was to look at star systems in which the Kepler space telescope had discovered planets. “We actually received not the best grade from the time allocation committee at Green Bank,” he says. “They gave us a C, because I think they were a little bit suspicious about whether we would actually be able to do it, but luckily, even though it wasn’t highly ranked, we still got the time.”

    Breakthrough Listen will take advantage of the data from Siemion’s work with Green Bank, but more importantly, it comes at a crucial time for the observatory. Constructed in a valley in the West Virginia mountains, the Green Bank Telescope opened in 2000 as part of the National Radio Astronomy Observatory. NRAO is funded by the National Science Foundation and runs several facilities, including the Very Large Array in New Mexico and the Atacama Large Millimeter/Submillimeter Array, or ALMA, in Chile (“The Universe’s Baby Boom,” Aug. 2013).

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, New Mexico.
    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, New Mexico

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array

    But in 2012, NSF issued a report on the next 10 years of astronomy research that recommended pulling Green Bank’s funding by 2017, because some of its research abilities are duplicated at larger facilities like the VLA and Arecibo Observatory. Now SETI—usually the research area struggling for funding—has come along with Breakthrough Listen at just the right moment, providing a reason and the means to keep the telescope operating while its staff looks for additional funding.

    5
    Russian billionaire Yuri Milner announces Breakthrough Listen last July alongside Stephen Hawking, Martin Rees, Frank Drake, and Ann Druyan. (Breakthrough Initiatives)

    One of Green Bank’s advantages is that it’s cocooned in the 13,000-square-mile National Radio Quiet Zone, where radio transmitters, cellphone towers, wifi networks, and other technology are limited by state and federal regulations. Scientists there would have an easier time determining if a signal in their observations is a message from another planet rather than a local teenager’s text. “One of the hardest things to do is tease out a signal from another civilization in the radio observations,” says Karen O’Neil, the Green Bank Observatory site director. “There are a lot of repeating patterns, but they’re all man-made.”

    Green Bank’s receivers are so sensitive they can detect the crackle of spark plugs in a gasoline-powered engine, so only diesel vehicles are allowed within a mile of the dish. The microwave oven in the observatory’s cafeteria sits inside a shielded box, and once the telescope even picked up interference from a small current generated by a wet dog lying down on an old heating pad. Staff members drive around in a pickup truck equipped with scanning equipment to track down stray electromagnetic signals, and sometimes lend a hand to help repair or replace offending devices in nearby businesses and homes.

    SETI is using some of the project funding to expand Green Bank’s computer capabilities far beyond those of any previous radio SETI project. The system will be able to process and store as much data in a single day as existing projects do in a year or more. Then it’s sent out to the SETI team at Berkeley and SETI@Home volunteers for analysis. The extra processing and storage capabilities are necessary because Breakthrough Listen will scan billions of radio channels between 1 and 10 gigahertz. Earlier surveys have been able to scan no more than a few hundred million channels at a time, with about half the spectral range. “We probably have a trillion times better capabilities today than when I started 40 years ago,” says Werthimer.

    That sensitivity should allow the telescopes to pick up intelligent signals not meant for us, something that couldn’t have been done before the Kepler mission provided astronomers with exoplanet locations. “There’s speculation that an advanced civilization might colonize another planet in its own solar system, like we might do with Mars,” says Werthimer. “They might send messages back and forth between planets, and we could pick up the signals when they line up with Earth.” In addition to the nearest million stars to Earth, the SETI group will monitor the densely packed center of the Milky Way galaxy, about 27,000 light-years away. “Our solar system is about five billion years old,” says Werthimer. “Some stars are 10 billion years old, so there could be some very advanced civilizations out there.” And finally, Breakthrough Listen will stretch its search out even farther, to 100 nearby galaxies where super-civilizations might be blasting messages between solar systems.

    7
    SETI will tune into Planet -452b (concept opposite) and other exoplanets found by NASA’s Kepler. (NASA/JPL-Caltech/T. Pyle)

    While the Green Bank Telescope searches in the northern hemisphere, Breakthrough Listen will use the Parkes Telescope near Sydney, Australia, to search the southern sky. The 210-foot movable dish is best known for transmitting most of the Apollo 11 moon landing video for the worldwide television broadcast (the event was fictionalized in the 2000 movie The Dish). The project will use about 20 percent of the observing time on each telescope, a jump from the few dozen cumulative hours SETI usually gets annually to thousands of hours.

    The third facility SETI is using will look instead of listen. The Automated Planet Finder, a 96-inch optical telescope at Lick Observatory, outside San Jose, California, will devote 10 percent of its time to searching for interstellar lasers.

    Lick Automated Planet Finder telescope
    Lick Automated Planet Finder telescope

    “If we took our own highest-powered lasers and paired them with our largest telescopes, we could send a beam that would outshine the sun by a factor of 10 at a distance of 1,000 light-years,” says Siemion. “Perhaps other civilizations are doing that to contact other civilizations, or to transmit a large amount of information.” It would be the equivalent of a Galaxy Wide Web.

    8
    The Parkes Observatory in Australia (opposite) is Breakthrough Listen’s outpost to eavesdrop on alien communication between star systems. (Daniel Sallai)

    Of course, not everyone is optimistic about the chances of Breakthrough Listen or any other SETI project finding evidence of neighboring civilizations, but not necessarily because they don’t believe in aliens. “Listening for intentional messages seems like a lost cause,” says Paul Davies, a researcher at Arizona State University and author of The Eerie Silence, a book that posits that current searches for intelligent life are flawed. “I’ve argued that we should be looking for other things: beacons, or probes, or alien artifacts in our own solar system. We have no idea how a super-civilization would manifest itself. It could be genetic—we could find signs in terrestrial biology…. There’s a good chance we might be alone in the universe. So we should search, but we shouldn’t spend a lot of money on it.”

    Even Werthimer doesn’t expect to hear from extraterrestrials anytime soon. “I’m optimistic in the long run,” he says. “We Earthlings are a young, emerging civilization. We’re just getting in the game, so a thorough search will take a while…. We probably won’t see anything in the next 10 years, so we’ll have to devise a new plan after that. Maybe, if the trend in computing power keeps going, we’ll find ET in 30 years.”

    In the meantime, let the eavesdropping begin.

    See the full article here.

    Prelude to the Breakthrough Project

    UC Santa Cruz
    From UCO Lick
    March 23, 2015

    Hilary Lebow

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    8
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch)

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    4
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

    See the full article here.

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  • richardmitnick 4:43 pm on May 26, 2016 Permalink | Reply
    Tags: Astronomy, , , , Mars Is Emerging From an Ice Age   

    From Science: “Mars Is Emerging From an Ice Age” 

    Astronomy magazine

    Astronomy.com

    May 26, 2016
    Jordan Rice

    A changing climate may be headed Mars’ way after a prolonged ice age.

    1
    NASA/JPL-Caltech/MSSS

    New observations suggest that Mars has very periodic ice ages showing that the polar ice caps grow and shrink as the planet warms or cools similar to Earth.

    In a new article* in Science, Isaac Smith and his colleagues were able to determine that the Red Planet is emerging from an ice age after many rounds of climate change chiefly by the dynamic movement of ice on the planet. These observations were found utilizing the Shallow Radar instrument on NASA’s Mars Reconnaissance Orbiter (MRO). These climate change patterns may help scientists understand climate patterns on Earth.

    NASA/Mars Reconnaissance Orbiter
    NASA/Mars Reconnaissance Orbiter

    The Shallow Radar instrument on the MRO uses radio signals that get beamed down onto the ice caps of Mars, which then return to the instrument some time later. Measuring this time delay between the signals along with tracing out the entire ice cap by the orbiter, Smith and his team got a profile of the entire ice cap down to 300 meters below the surface.

    “Layers tell us the history of accumulation, which is basically the history of climate,” says Smith.

    As they took readings across the entire Northern ice cap they found that the top part of the ice cap was not simply changing in one spot, but was happening simultaneously everywhere.

    “Things can be 1000 kilometers apart and they are still happening simultaneously,” Smith says. “This gives the idea that there was a climate change that was recorded right there at that level.”

    As this level is the top layer of ice, this infers that the change is happening now. Currently, the water is tied up at the poles, but in the past it is expected that the water and ice would have been more spread out across the mid-latitude regions rather than being kept at the poles. As more of the surface of the planet is covered in ice, this increases the reflectiveness of the planet, causing more sunlight to be reflected back into space and for the overall temperature of the planet to decrease.

    “If you looked at Mars during this period, it would be more white than red,” says Smith. “Its color would change.”

    Another factor that forces climate change on Mars are Milankovitch cycles. These are cycles that affect the axial tilt and elongation of the orbit. As Mars’ axial tilt can vary from zero to 60 degrees, while the Earth’s stays steady at 23 degrees, these changes can affect how much light reaches the poles or equator of Mars. The elongation of Mars’ orbit has the same effect, as the planet can be closer or further away from the sun determining the amount of light reaches the surface.

    “Really light is the biggest energy in the equation,” says Smith. “That is what causes the ice ages, the change in light.”

    Smith and his colleagues still have a lot of research to conduct on the ice caps of Mars. As the Northern ice cap is 2000 meters thick, the next step is to probe even deeper to see if they can find similar signatures, says Smith. After receiving more radar data from the MRO, they want to begin to look for climate change in these deeper layers. There is current research looking at the mid-latitude ice and are finding that it is being removed constantly.

    “We want to quantify how much is being removed and compare that to how much has been deposited on the poles,” says Smith.

    These observations found on Mars can be applied to the Earth as well. Mars can be simplified as a laboratory for Earth as the systems that affect the planet are much simpler than Earth’s says Smith. With Earth possessing oceans and life, it complicates the model significantly. As Mars does not have these systems, Smith and his team can get a better understanding of the physics that goes into these models.

    “Once we understand the physics, we can match the observations to the model,” Smith says. “We can take what we’ve learned and apply it to Earth.”

    *Science article:
    An ice age recorded in the polar deposits of Mars

    See the full article here .

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  • richardmitnick 3:52 pm on May 26, 2016 Permalink | Reply
    Tags: , Astronomy, , , How would our Universe be different without dark energy?   

    From Ethan Siegel: “How would our Universe be different without dark energy?” 

    From Ethan Siegel

    5.26.16

    1
    Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona, of the Hercules Galaxy Cluster, under a c.c.a.-s.a.-4.0 license.

    U Arizona Mt Lemmon Sky Center, north of Tuscon, AZ, USA
    U Arizona Mt Lemmon Sky Center, north of Tuscon, AZ, USA

    In 1998, cosmologists got the surprise of a lifetime. Here’s how our Universe would’ve looked without cosmic acceleration.

    “We’ve known for a long time that the universe is expanding. But about 15 years ago, my colleagues and I discovered that it is expanding faster and faster. That is, the universe is accelerating, and that was not expected, but it is now attributed to this mysterious stuff called dark energy which seems to make up about 70 percent of the universe.” -Adam Riess

    In 1998, two independent groups of scientists both studying the most distant supernova explosions in the Universe reported the same unexpected phenomenon: these brilliant flashes of light, whose intrinsic brightnesses and redshifts were known to great precision, all had a problem, that they appeared to be much fainter than expected. And the higher of a redshift you went to, the greater this problem got. The interpretation? They were more distant — and hence appeared less bright — than the conventional version of the expanding Universe would have predicted. Rather than being filled only with matter and radiation throughout the fabric of space, the Universe also contained this small but important amount of energy inherent to space itself: dark energy.

    2
    Image credit: Ned Wright, based on the latest data from Betoule et al. (2014), via http://www.astro.ucla.edu/~wright/sne_cosmology.html.

    As our measurements got better and better, and as we accumulated data from other sources as well, like the fluctuations in the Cosmic Microwave Background (CMB) and the clustering properties of large-scale structure, we found out that approximately 68% of the energy in the Universe today was this mysterious dark energy. Yes, there was dark matter, normal matter, neutrinos and radiation all present, and they were all vital to how the Universe expanded and evolved, particularly at early times. But as the Universe aged, dark energy became more and more important, and will eventually approach a full 100% of the energy present within our Universe.

    3
    Constraints on dark energy from three independent sources: supernovae, the CMB and BAO. Note that even without supernovae, we’d need dark energy. Image credit: Supernova Cosmology Project, Amanullah, et al., Ap.J. (2010).

    But according to General Relativity, it didn’t have to be this way at all. We could have had a Universe with no dark energy at all: where zero-point energy of empty space was actually zero, instead of some tiny, non-zero value. If that were our Universe, how would it be different from the Universe we have today? Surprisingly, there are a few significant ways that really make an impact.

    4
    A Universe with dark energy: our Universe. Image credit: NASA / WMAP Science Team.

    1.) The Universe would be a little bit different. Right now, in our 13.8 billion year old Universe, 32% of the energy density is in the form of matter, 68% is dark energy, the expansion rate is 67 km/s/Mpc and the limits of our observable reach is 46.1 billion light years. If wanted the Universe to have the same exact amount of matter in it, but with no dark energy, our Universe would have expanded faster early on, and would be expanding slower today. It would:

    be 47.7 billion light years in size, rather than 46.1 billion,
    have a current Hubble rate of 56 km/s/Mpc rather than 67 km/s/Mpc,
    the CMB temperature would be just slightly lower, at 2.62 K instead of 2.73 K,
    and have a whopping 71% less energy overall, due to the total lack of dark energy.

    But the major differences would show up far in the future, especially when we considered our eventual fates.

    5
    The GOODS-N field, with galaxy GN-z11 highlighted: the presently most-distant galaxy ever discovered. Image credit: NASA, ESA, P. Oesch (Yale University), G. Brammer (STScI), P. van Dokkum (Yale University), and G. Illingworth (University of California, Santa Cruz).

    2.) Every galaxy in the visible Universe would still be reachable.

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey
    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    In our dark-energy dominated Universe, the rate a distant galaxy recedes from us increases as time goes on. Galaxies presently more than 15 billion light years away are receding faster than the speed of light [?], and so nothing leaving Earth today — not a relativistic spaceship, not a deep-space probe, not even light itself — could ever reach it. Already, 97% of the galaxies in our Universe are forever beyond our reach. But if we were to take that dark energy away, everything would be reachable eventually, even if it took tens or hundreds of billions of years. We’d get there in the end.

    6
    A portion of the Hubble eXtreme Deep Field in full UV-vis-IR light, the deepest image ever obtained. Image credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI).

    3.) New galaxies beyond our horizon would continually become accessible. Not only that, but even galaxies whose light has never reached us yet will someday have that light catch up to us in the future! While a dark energy Universe has the currently visible galaxies “red out,” or redshift away to the point where they’ll no longer be seen in the far future, a Universe without it would’ve seen additional galaxies become visible over time, with more and more becoming apparent (and reachable) as time goes on.

    7
    Without dark energy, we’d be somewhere in between a decelerating and a coasting Universe. Image credit: NASA & ESA, of possible models of the expanding Universe.

    4.) The Hubble rate of expansion would eventually drop to zero. It would never actually reach zero, mind you, and it would never turn around and recollapse: there’s too little energy for that overall. But the Hubble rate would asymptotically approach zero as the Universe continued to expand, meaning that if an infinite amount of time were to pass, an infinite number of galaxies (though not all of them, by any means) would become accessible. With dark energy, our Universe’s Hubble rate will asymptote to a finite, significant value after an infinite amount of time: something like 46 km/s/Mpc. Without dark energy, we’d have dropped below that 46 km/s/Mpc rate after another 4.3 billion years.

    Laniakea supercluster no image credit
    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    5.) Superclusters would really exist. Our local supercluster, containing the local group, the Virgo Cluster (the largest supercluster member) and hundreds of other individual galaxies, groups and clusters, doesn’t really exist thanks to dark energy.

    Local Group. Andrew Z. Colvin 3 March 2011
    Local Group. Andrew Z. Colvin 3 March 2011

    Virgo Supercluster
    Virgo Supercluster. No image credit

    It looks like a large structure, but it’s not bound together and will have all of its individual components strewn apart as time goes on. But without that additional repulsion that dark energy imparts, gravitation would win in the end. On long enough timescales, all galaxies, groups and clusters that make up the Laniakea supercluster will remain bound together, and will continue to experience mergers on cosmic scales.

    6.) Which means eventually, Milkdromeda would fall into the Virgo Cluster. At 50–60 million light years distant, the Virgo Cluster contains around 1000 galaxies, and is the closest galaxy cluster to our local group. It’s currently receding from us, due to the expansion of the Universe, at over 1000 km/s, or about 100 times faster than any human-made spacecraft has ever traveled. With dark energy, Virgo will only accelerate away from us faster and faster. But if it weren’t there, the gravitational pull of Virgo would be irresistible, and even though it would take around a hundred billion years — many times the age of the Universe at present — eventually the galactic wreckage of our local group would merge with the Virgo cluster as well.

    8
    Image credit: E. Siegel, based on work by Wikimedia Commons users Andrew Colvin 429 and Frédéric MICHEL.

    With dark energy, the subtle differences of a slightly more energetic and more rapidly expanding Universe today leads to a far future where our local group is lonely and isolated, distant galaxies disappear from view and there’s no such thing as a bound, cosmic supercluster. On the largest scales, the Universe is doomed to emptiness, and it’s extra energy intrinsic to space itself that’s to blame. Part of why it was so hard to accept is because the fate of a dark energy Universe is so different — and unpalatable — from a Universe without it. Yet science doesn’t care about your personal preferences or motivations: it cares about the Universe as it actually is. The best thing we can do is listen to the story it tells us about itself, and in a way, about ourselves, too.

    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 1:53 pm on May 26, 2016 Permalink | Reply
    Tags: Astronomy, , , Gliese 581d   

    From CosmosUP: “Gliese 581d: Earth-like World Within Our Reach” 

    CosmosUp bloc

    CosmosUp

    25, May 2016
    NASA astronomers said they’ve discovered a planet that they believe has a 100% chance of having life on it and its relatively close to us, just in our cosmic neighborhood — meet Gliese 581d.

    Gliese 581 is a red dwarf star located about 20 light-years away from Earth in the constellation Libra — One light-year is about 6 trillion miles (10 trillion km); Out of the billions of stars in the sky, Gliese 581 is the 89th closest known star to the Sun.

    In 2005, astronomers found six exoplanets orbiting their star in nearly circular paths and they were named as Gliese b, c, d, f and g; they used the indirect method to found these planets, which mean that the planets cannot be viewed with a telescope; Astronomers used radial velocity data on the star. This method looks at a star’s tiny movements due to the gravitational tug from orbiting bodies. The subtle tugs let researchers estimate the planet’s mass and how long it takes to circle its star.

    It was calculated that Gliese 581d is in the perfect not-too-hot not-too-cold Goldilocks zone, just the ideal distance away from the start to be able to support life; in fact, some astronomers are 100% certain that they do:

    “Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent,

    said Steven Vogt, a professor of astronomy and astrophysics at the University of California, Santa Cruz.

    I have almost no doubt about it.”

    But are we sure abut this planet? Well, many so called habitable exoplanets have been found and later discredited so there’s still a chance that further observations will dismiss this planet. Actually, in 2014 there was a study that claimed the super-Earth planets GJ 581d does not exist, but is actually an artifact of noise and stellar activity, but reanalysis suggests that it does in fact exist, despite stellar variability.

    Gliese 581d’ mass is thought to be 6.98 Earths and its radius is thought to be 2.2 Earth’s radius. It is considered to be a super-Earth with a solid surface allowing for any water present on its surface to form liquid oceans and an atmosphere and even landmasses characteristic of Earth’s surface.

    “The Gliese system is particularly exciting to us as it’s very close to Earth, relatively speaking. So with future generations of telescopes, we’ll be able to search for life on Gliese 581d directly.”

    said Robin Wordsworth.

    1

    Gliese 581d is a key target for the upcoming James Webb Space Telescope (JWST). The infrared James Webb Space Telescope (JWST), due to launch in 2018, is predicted to dramatically change our understanding of exoplanet atmospheres.

    JWST might provide the atmospheric data for Gliese 581d and determine whether this planet may be in the liquid water habitable zone of its star and thus if its capable of supporting life.

    “This technology we are using to explore exoplanets is real,

    added John Grunsfeld, astronaut and associate administrator for NASA’s Science Mission Directorate.

    The James Webb Space Telescope and the next advances are happening now. These are not dreams — this is what we do at NASA.”

    NASA/ESA/CSA Webb Telescope annotated
    “NASA/ESA/CSA Webb Telescope annotated
    “It’s within our grasp to pull off a discovery that will change the world forever,

    he said in a statement.

    Just imagine the moment, when we find potential signatures of life. Imagine the moment when the world wakes up and the human race realizes that its long loneliness in time and space may be over – the possibility we’re no longer alone in the Universe.”

    Since its discovery, a massive campaign went into beaming a message from Earth to Gliese system including over 500 messages selected from over half a million entries, using the RT-70 radar telescope of Ukraine’s National Space Agency.

    3
    RT-70 radar telescope of Ukraine’s National Space Agency

    Gliese 581d a World of possibilities

    Could this actually be our closest life supporting neighbor… only 20 light years away? If so, what might life there be like?

    “Any discussion about alien life on Gliese 581g is purely speculative at this point,

    according to co-discoverer Paul Butler of the Carnegie Institution of Washington.

    But anywhere you find water on Earth, you find life. A similar condition should hold for almost anywhere in the universe, including Gliese 581g if it does hold water.”

    Beside this planet, scientists estimates that there are tens of billions of potentially habitable planets may exist, waiting to be found.

    “I would venture to say that most of my colleagues here today say it is improbable that in the limitless vastness of the Universe we humans standalone.”

    See the full article here .

    Please help promote STEM in your local schools.

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