Planetary Defense Campaign Will Use Real Asteroid For The First Time

For the first time, NASA will use an actual space rock for a tabletop exercise simulating an asteroid impact in a densely populated area. The asteroid, named 2012 TC4, does not pose a threat to Earth, but NASA is using it as a test object for an observational campaign because of its close flyby on Oct. 12, 2017.

NASA has conducted such preparedness drills rehearsing various aspects of an asteroid impact, such as deflection, evacuation, and disaster relief, with other federal entities in the past. Traditionally, however, these exercises involved hypothetical impactors, prompting Vishnu Reddy of the University of Arizona’s Lunar and Planetary Laboratory to propose a slightly more realistic scenario, one that revolves around an actual near-Earth asteroid, or NEA.

“The question is, how prepared are we for the next cosmic threat?” says Reddy, an assistant professor of planetary science at the Lunar and Planetary Laboratory. “So we proposed an observational campaign to exercise the network and test how ready we are for a potential impact by a rogue asteroid.”

NASA’s Planetary Defense Coordination Office (PDCO), the federal entity in charge of coordinating efforts to protect Earth from hazardous asteroids, accepted Reddy’s proposal to conduct an observational campaign as part of assessing its Earth-based defense network. Reddy will assist Michael Kelley, who serves as a program scientist with NASA PDCO and the civil servant lead on the exercise.

The goal of the TC4 exercise is to recover, track, and characterize 2012 TC4 as a potential impactor in order to exercise the entire system from observations, modeling, prediction, and communication.

Measuring between 30 and 100 feet, roughly the same size as the asteroid that exploded over Chelyabinsk, Russia, on Feb. 15, 2013, TC4 was discovered by the Pan-STARRS 1 telescope on Oct. 5, 2012, at Haleakala Observatory on Maui, Hawaii. Given its orbital uncertainty, the asteroid will pass as close as 6,800 kilometers (4,200 miles) above Earth’s surface.

“This is a team effort that involves more than a dozen observatories, universities, and labs across the globe so we can collectively learn the strengths and limitations of our planetary defense capabilities,” said Reddy, who is coordinating the campaign for NASA PDCO.

Since its discovery in 2012, the uncertainty in the asteroid’s orbit has slowly increased, as it would for any asteroid as time passes. Therefore, the first order of business will be to “recover” the object—in other words, nail down its exact path. Reddy and his collaborators hope that depending on its predicted brightness, the asteroid would be visible again to large ground-based telescopes in late August.

“One of the strengths of UA research is partnering with federal agencies or industry to work together in solving some of the grand challenges we face,” said Kimberly Andrews Espy, senior vice president for research. “This project is a perfect example of matching UA capabilities—from our world-class imaging to our expertise in space sciences—with an external need.”

The UA is home to the Catalina Sky Survey, one of the most prolific asteroid discoverers, and the Spacewatch project that recovers and tracks faint NEAs. Both teams will take part in the planetary defense exercise.

Scientists Find Moon Of Saturn Has Chemical That Could Form ‘Membranes’

NASA scientists have definitively detected the chemical acrylonitrile in the atmosphere of Saturn’s moon Titan, a place that has long intrigued scientists investigating the chemical precursors of life.

On Earth, acrylonitrile, also known as vinyl cyanide, is useful in the manufacture of plastics. Under the harsh conditions of Saturn’s largest moon, this chemical is thought to be capable of forming stable, flexible structures similar to cell membranes. Other researchers have previously suggested that acrylonitrile is an ingredient of Titan’s atmosphere, but they did not report an unambiguous detection of the chemical in the smorgasbord of organic, or carbon-rich, molecules found there.

Now, NASA researchers have identified the chemical fingerprint of acrylonitrile in Titan data collected by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. The team found large quantities of the chemical on Titan, most likely in the stratosphere—the hazy part of the atmosphere that gives this moon its brownish-orange color.

“We found convincing evidence that acrylonitrile is present in Titan’s atmosphere, and we think a significant supply of this raw material reaches the surface,” said Maureen Palmer, a researcher with the Goddard Center for Astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of a July 28, 2017, paper in Science Advances.

The cells of Earth’s plants and animals would not hold up well on Titan, where surface temperatures average minus 290 degrees Fahrenheit (minus 179 degrees Celsius), and lakes brim with liquid methane.

In 2015, university scientists tackled the question of whether any organic molecules likely to be on Titan could, under such inhospitable conditions, form structures similar to the lipid bilayers of living cells on Earth. Thin and flexible, the lipid bilayer is the main component of the cell membrane, which separates the inside of a cell from the outside world. This team identified acrylonitrile as the best candidate.

Those researchers proposed that acrylonitrile molecules could come together as a sheet of material similar to a cell membrane. The sheet could form a hollow, microscopic sphere that they dubbed an “azotosome.” This sphere could serve as a tiny storage and transport container, much like the spheres that lipid bilayers can form.

“The ability to form a stable membrane to separate the internal environment from the external one is important because it provides a means to contain chemicals long enough to allow them to interact,” said Michael Mumma, director of the Goddard Center for Astrobiology, which is funded by the NASA Astrobiology Institute. “If membrane-like structures could be formed by vinyl cyanide, it would be an important step on the pathway to life on Saturn’s moon Titan.”

The Goddard team determined that acrylonitrile is plentiful in Titan’s atmosphere, present at concentrations up to 2.8 parts per billion. The chemical is probably most abundant in the stratosphere, at altitudes of at least 125 miles (200 kilometers). Eventually, acrylonitrile makes its way to the cold lower atmosphere, where it condenses and rains out onto the surface.

The researchers calculated how much material could be deposited in Ligeia Mare, Titan’s second-largest lake, which occupies roughly the same surface area as Earth’s Lake Huron and Lake Michigan together. Over the lifetime of Titan, the team estimated, Ligeia Mare could have accumulated enough acrylonitrile to form about 10 million azotosomes in every milliliter, or quarter-teaspoon, of liquid. That’s compared to roughly a million bacteria per milliliter of coastal ocean water on Earth.

The key to detecting Titan’s acrylonitrile was to combine 11 high-resolution data sets from ALMA. The team retrieved them from an archive of observations originally intended to calibrate the amount of light being received by the telescope array.

In the combined data set, Palmer and her colleagues identified three spectral lines that match the acrylonitrile fingerprint. This finding comes a decade after other researchers inferred the presence of acrylonitrile from observations made by the mass spectrometer on NASA’s Cassini spacecraft.

“The detection of this elusive, astrobiologically relevant chemical is exciting for scientists who are eager to determine if life could develop on icy worlds such as Titan,” said Goddard scientist Martin Cordiner, senior author on the paper. “This finding adds an important piece to our understanding of the chemical complexity of the solar system.”

Milky Way’s Origins Are Not What They Seem

In a first-of-its-kind analysis, Northwestern University astrophysicists have discovered that, contrary to previously standard lore, up to half of the matter in our Milky Way galaxy may come from distant galaxies. As a result, each one of us may be made in part from extragalactic matter.

Using supercomputer simulations, the research team found a major and unexpected new mode for how galaxies, including our own Milky Way, acquired their matter: intergalactic transfer. The simulations show that supernova explosions eject copious amounts of gas from galaxies, which causes atoms to be transported from one galaxy to another via powerful galactic winds. Intergalactic transfer is a newly identified phenomenon, which simulations indicate will be critical for understanding how galaxies evolve.

“Given how much of the matter out of which we formed may have come from other galaxies, we could consider ourselves space travelers or extragalactic immigrants,” said Daniel Anglés-Alcázar, a postdoctoral fellow in Northwestern’s astrophysics center, CIERA (Center for Interdisciplinary Exploration and Research in Astrophysics), who led the study. “It is likely that much of the Milky Way’s matter was in other galaxies before it was kicked out by a powerful wind, traveled across intergalactic space and eventually found its new home in the Milky Way.”

Galaxies are far apart from each other, so even though galactic winds propagate at several hundred kilometers per second, this process occurred over several billion years.

Professor Claude-André Faucher-Giguère and his research group, along with collaborators from the FIRE (“Feedback In Realistic Environments”) project, which he co-leads, had developed sophisticated numerical simulations that produced realistic 3-D models of galaxies, following a galaxy’s formation from just after the Big Bang to the present day. Anglés-Alcázar then developed state-of-the-art algorithms to mine this wealth of data and quantify how galaxies acquire matter from the universe.

The study, which required the equivalent of several million hours of continuous computing, will be published July 26 (July 27 in the U.K.) by the Monthly Notices of the Royal Astronomical Society.

“This study transforms our understanding of how galaxies formed from the Big Bang,” said Faucher-Giguère, a co-author of the study and assistant professor of physics and astronomy in the Weinberg College of Arts and Sciences.

“What this new mode implies is that up to one-half of the atoms around us — including in the solar system, on Earth and in each one of us — comes not from our own galaxy but from other galaxies, up to one million light years away,” he said.

By tracking in detail the complex flows of matter in the simulations, the research team found that gas flows from smaller galaxies to larger galaxies, such as the Milky Way, where the gas forms stars. This transfer of mass through galactic winds can account for up to 50 percent of matter in the larger galaxies.

“In our simulations, we were able to trace the origins of stars in Milky Way-like galaxies and determine if the star formed from matter endemic to the galaxy itself or if it formed instead from gas previously contained in another galaxy,” said Anglés-Alcázar, the study’s corresponding author.

In a galaxy, stars are bound together: a large collection of stars orbiting a common center of mass. After the Big Bang 14 billion years ago, the universe was filled with a uniform gas — no stars, no galaxies. But there were tiny perturbations in the gas, and these started to grow by force of gravity, eventually forming stars and galaxies. After galaxies formed, each had its own identity.

“Our origins are much less local than we previously thought,” said Faucher-Giguère, a CIERA member. “This study gives us a sense of how things around us are connected to distant objects in the sky.”

The findings open a new line of research in understanding galaxy formation, the researchers say, and the prediction of intergalactic transfer can now be tested. The Northwestern team plans to collaborate with observational astronomers who are working with the Hubble Space Telescope and ground-based observatories to test the simulation predictions.

The simulations were run and analyzed using the National Science Foundation’s Extreme Science and Engineering Discovery Environment supercomputing facilities, as well as Northwestern’s Quest high-performance computer cluster.

Eclipse On August 21 Offers Unique Research Opportunities

In a briefing today on solar eclipse science, leading U.S. scientists highlighted research projects that will take place across the country during the upcoming August 21 solar eclipse. The research will advance our knowledge of the sun’s complex and mysterious magnetic field and its effects on Earth’s atmosphere and land.

Experts at the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA) and the National Center for Atmospheric Research (NCAR) discussed how scientists from coast to coast are preparing to deploy an array of technologies and methodologies to gain unprecedented views of the sun.

The experiments, led by specialized researchers, will also draw on observations by amateur sky watchers and students.

“This total solar eclipse across the United States is a unique opportunity in modern times, enabling the entire country to be engaged through modern technology and social media,” said Carrie Black, a program director in NSF’s Division of Atmospheric and Geospace Sciences. “Images and data from as many as millions of people will be collected and analyzed by scientists for years to come.”

“This is a generational event,” agreed Madhulika Guhathakurta, NASA lead scientist for the 2017 Eclipse. “This is going to be the most documented, the most appreciated, eclipse ever.”

The scientific experiments will take place along the path of totality, a 70-mile-wide ribbon where the moon will completely cover the sun; it stretches from Oregon to South Carolina.

Viewers in any one location may experience the total eclipse for as long as two minutes and 40 seconds. It will take about an hour and a half for the eclipse to travel across the sky from the Pacific Coast to the Atlantic.

For scientists, the celestial event is a rare opportunity to observe the elusive solar corona, the sun’s outer atmosphere, which is usually obscured by the sun’s bright surface.

Many scientific questions focus on the corona: Why is it much hotter than the sun’s surface? What role does it play in spewing large streams of charged particles, known as coronal mass ejections, which strike Earth’s atmosphere and can disrupt GPS systems and other sensitive technologies?

Black noted that during the eclipse the moon will align exactly with the sun’s surface and enable observations of the entire corona, including regions that are rarely detectable. “The moon is about as perfect an occulter as one can get,” she said.

Obtaining observations from the ground will play a particularly important part in the experiments, she explained, because far more data can be transmitted than would be possible from space-based instruments.

In addition to focusing ground-based instruments on the sun, scientists will also deploy aircraft to follow the eclipse, thereby increasing the amount of time they can make observations.

An NCAR research team, for example, will use the NSF/NCAR Gulfstream-V research aircraft to take infrared measurements for about four minutes, helping scientists better understand the solar corona’s magnetism and thermal structure.

Scientists at the Southwest Research Institute in Boulder, Colorado, will use visible and infrared telescopes on NASA’s twin WB-57 airplanes to enable a unique look at both the solar corona and Mercury for about eight minutes. The goals are to better understand the movement of energy through the corona and to learn more about the composition and properties of Mercury’s surface.

During the eclipse, scientists will also study Earth’s outer atmosphere, the ionosphere, a region of the atmosphere containing particles that are charged by solar radiation. Disturbances in the ionosphere can affect radio waves. Because the eclipse blocks energy from the sun, scientists can study the ionosphere’s response to a sudden drop in solar radiation.

For example, a Boston University research team will use off-the-shelf cellphone technology to construct a single-frequency GPS array of sensors to study the ionospheric effects of the eclipse. This project could lay the foundation for using consumer smartphones to help monitor the outer atmosphere for disturbances caused by solar storms.

In another experiment, a Virginia Tech team will use a network of radio receivers and transmitters across the country to observe the ionosphere, while researchers at the University of Virginia and George Mason University will use transmitters broadcasting at low frequencies to probe various regions of the ionosphere.

Citizen scientists are expected to play a major role in making valuable observations during the eclipse. “This is a social phenomenon, and we have a significant opportunity to promote this and do all the science we can,” Guhathakurta said. Black added, “What makes this an even more valuable opportunity is that everyone has access to it.”

The Citizen Continental-America Telescopic Eclipse (CATE) Experiment by the National Solar Observatory, for example, will rely on volunteers from universities, high schools, informal education groups, and national labs for an eclipse “relay race.” Participants spaced along the path of totality will use identical telescopes and digital camera systems to capture high-quality images that will result in a dataset capturing the entire 93-minute eclipse across the country.

And a project led by the University of California, Berkeley, will assemble a large number of solar images, obtained along the eclipse path by students and amateur observers, to create educational materials as part of an “Eclipse Megamovie.”

“As these projects show, the eclipse will place the sun firmly in the forefront of the national eye,” said Scott McIntosh, director of NCAR’s High Altitude Observatory. “This is a unique opportunity to communicate the fact that our star is complex, beautiful and mysterious. At the same time, it’s more critical than ever to study it, as solar activity can pose significant threats to our technologically driven society.”

Astrophysicists Map Out The Light Energy Contained Within The Milky Way

For the first time, a team of scientists has calculated the distribution of all light energy contained within the Milky Way, which will provide new insight into the make-up of our galaxy and how stars in spiral galaxies such as ours form. The study is published in the journal Monthly Notices of the Royal Astronomical Society.

This research, conducted by astrophysicists at the University of Central Lancashire (UCLan), in collaboration with colleagues from the Max Planck Institute for Nuclear Physics in Heidelberg, Germany and from the Astronomical Institute of the Romanian Academy, also shows how the stellar photons, or stellar light, within the Milky Way control the production of the highest energy photons in the Universe, the gamma-rays. This was made possible using a novel method involving computer calculations that track the destiny of all photons in the galaxy, including the photons that are emitted by interstellar dust, as heat radiation.

Previous attempts to derive the distribution of all light in the Milky Way based on star counts have failed to account for the all-sky images of the Milky Way, including recent images provided by the European Space Agency’s Planck Space Observatory, which map out heat radiation or infrared light.

Lead author Prof Cristina Popescu from the University of Central Lancashire, said: “We have not only determined the distribution of light energy in the Milky Way, but also made predictions for the stellar and interstellar dust content of the Milky Way.”

By tracking all stellar photons and making predictions for how the Milky Way should appear in ultraviolet, visual and heat radiation, scientists have been able to calculate a complete picture of how stellar light is distributed throughout our Galaxy. An understanding of these processes is a crucial step towards gaining a complete picture of our Galaxy and its history.

The modelling of the distribution of light in the Milky Way follows on from previous research that Prof Popescu and Dr Richard Tuffs from the Max Planck Institute for Nuclear Physics conducted on modelling the stellar light from other galaxies, where the observer has an outside view.

Commenting on the research, Dr Tuffs, one of the co-authors of the paper, said: “It has to be noted that looking at galaxies from outside is a much easier task than looking from inside, as in the case of our Galaxy.”

Scientists have also been able to show how the stellar light within our Galaxy affects the production of gamma-ray photons through interactions with cosmic rays. Cosmic rays are high-energy electrons and protons that control star and planet formation and the processes governing galactic evolution. They promote chemical reactions in interstellar space, leading to the formation of complex and ultimately life-critical molecules.

Dr Tuffs added: “Working backwards through the chain of interactions and propagations, one can work out the original source of the cosmic rays.”

The research, funded by the Leverhulme Trust, was strongly interdisciplinary, bringing together optical and infrared astrophysics and astro-particle physics. Prof Popescu notes: “We had developed some of our computational programs before this research started, in the context of modelling spiral galaxies, and we need to thank the UK’s Science and Technology Facility Council (STFC) for their support in the development of these codes. This research would also not have been possible without the support of the Leverhulme Trust, which is greatly acknowledged.”

UPDATE: NSO Predicts Shape of Solar Corona for August 2017 Eclipse

The 2017 eclipse will offer a unique opportunity to observe the corona for more than 90 minutes, many times longer than a typical eclipse. However, NSO (National Solar Observatory) is preparing to change how we look at the solar corona forever. Using this observatory, which will house the most powerful solar telescope in the world, scientists will be able to consistently measure the magnetic fields in the solar corona directly for the very first time. “The solar corona is largely an enigma,” according to Dr. Valentin Pillet, Director of NSO.

“For now, the best we can do is compare high resolution images of the solar corona, such as those we’ll obtain during the eclipse, to our theoretical models. But DKIST will allow us to actually measure the magnetic fields in the corona. This will be revolutionary in the field of solar physics.”

Solar Corona Eclipse National Solar Observatory

But there is more to the corona than one might initially realize. Dr. Gordon Petrie from the National Solar Observatory (NSO) explains: “The corona might look like it’s a fuzzy halo around the Sun, but it actually has quite a lot of structure to it. The Sun has a magnetic field that, at first glance, might remind us of the middle-school experiment where you sprinkle iron filings over a bar magnet to get a butterfly shape. However, on closer inspection, it is far more complicated than that.”

The Sun’s magnetic field is rooted inside of the Sun, and protrudes through the surface leaving marks we recognize as Sunspots. Since we cannot directly observe magnetic fields, we use the super-heated gases present in the Sun’s atmosphere to trace out the magnetic field lines, similar to the role of iron filings in the aforementioned bar magnet experiment. Under normal circumstances, the solar corona – the outermost layer of the Sun’s atmosphere – is hidden from view by the bright solar surface. During an eclipse, the surface is blocked, allowing the corona to shine through.

“The corona changes its shape over time, and looks drastically different during solar maximum compared to solar minimum,” explains Dr. David Boboltz, the National Science Foundation’s program officer for the NSO. “During solar maximum, such as the 2012 eclipse, the corona looks like a spiky ring around the entire Sun. In contrast, a solar minimum eclipse such as the one this month, will have lots of complexity near the equator but will be drastically different near the north and south poles of the Sun.”

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