23 Apr 2017

RESEARCHERS PRODUCE DETAILED MAP OF POTENTIAL MARS ROVER LANDING SITE

Ashampoo_Snap_2017.04.22_23h09m43s_001_Brown University researchers have published the most detailed geological history to date for a region of Mars known as Northeast Syrtis Major, a spot high on NASA's list of potential landing sites for its next Mars rover to be launched in 2020.

The region is home to a striking mineral diversity, including deposits that indicate a variety of past environments that could have hosted life. Using the highest resolution images available from NASA's Mars Reconnaissance Orbiter, the study maps the extent of those key mineral deposits across the surface and places them within the region's larger geological context.

"When we look at this in high resolution, we can see complicated geomorphic patterns and a diversity of minerals at the surface that I think is unlike anything we've ever seen on Mars," said Mike Bramble, a Ph.D. student at Brown who led the study, which is published in the journal Icarus. "Within a few kilometres, there's a huge spectrum of things you can see and they change very quickly."

If NASA ultimately decides to land at Northeast Syrtis, the work would help in providing a roadmap for the rover's journey.

"This is a foundational paper for considering this part of the planet as a potential landing site for the Mars 2020 rover," said Jack Mustard, a professor in Brown's Department of Earth, Environmental and Planetary Sciences and a co-author on the paper. "This represents an exceptional amount of work on Mike's part, really going into the key morphologic and spectroscopic datasets we need in order to understand what this region can tell us about the history of Mars if we explore it with a rover."

Northeast Syrtis sits between two giant Martian landforms—an impact crater 2,000 kilometres in diameter called the Isidis Basin, and a large volcano called Syrtis Major. The impact basin formed about 3.96 billion years ago, while lava flow from the volcano came later, about 3.7 billion years ago. Northeast Syrtis preserves the geological activity that occurred in the 250 million years between those two events. Billions of years of erosion, mostly from winds howling across the region into the Isidis lowlands, have exposed that history on the surface.

Within Northeast Syrtis are the mineral signatures of four distinct types of watery and potentially habitable past environments. Those minerals had been detected by prior research, but the new map shows in detail how they are distributed within the region's larger geological context. That helps constrain the mechanisms that may have formed them, and shows when they formed
relative to each other.

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The lowest and the oldest layer exposed at Northeast Syrtis has the kind of clay minerals formed when rocks interact with water that has a fairly neutral pH. Next in the sequence are rocks containing kaolinite, a mineral formed by water percolating through soil. The next layer up contains spots where the mineral olivine has been altered to carbonate—an aqueous reaction that, on Earth, is known to provide chemical energy for bacterial colonies. The upper layers contain sulphate minerals, another sign of a watery, potentially life-sustaining environment.

Understanding the relative timing of these environments is critical, Mustard says. They occurred around the transition between the Noachian and Hesperian epochs—a time of profound environmental change on Mars.

"We know that these environments existed near this major pivot point in Mars history, and in mapping their context we know what came first, what came next and what came last," Mustard said. "So now if we're able to go there with a rover, we can sample rock on either side of that pivot point, which could help us understand the changes that occurred at that time, and test different hypotheses for the possibility of past life."

And finding signs of past life is the primary mission of the Mars2020 rover. NASA has held three workshops in which scientists debated the merits of various landing targets for the rover.

Mustard and Bramble have led the charge for Northeast Syrtis, which has come out near the top of the list at each workshop. Last February, NASA announced that the site is one of the final three under consideration.

Mustard and Bramble hope this latest work might inform NASA's decision, and ultimately help in planning the Mars2020 mission.

"As we turn our eyes to the next target for in situ exploration on the Martian surface," the researchers conclude, "no location offers better access of the gamut of geological processes active at Mars than Northeast Syrtis Major."

21 Apr 2017

McDonald Observatory dedicates $40 million upgrade

McDonald_Observatory-167_Courtesy%20of%20Ethan%20Tweedie%20Photography_0The University’s McDonald Observatory in West Texas dedicated its $40 million telescope upgrade last week and is now performing an in-depth study of a mysterious force known as dark energy.

The upgrade gives McDonald’s 10-meter telescope the ability to create a 3-D map of the universe to study dark energy, a little understood concept that could explain the accelerating expansion of the universe.

Photo Credit: Courtesy of Ethan Tweedie Photography | Daily Texan Staff

The telescope, the world’s third largest in size, can now see light that is close to 12 billion years old and can view 120 times more of the night sky than it previously could. Not even the largest telescope in the world at the Kek Observatory in Hawaii has as large of a field of view.

“It is sort of one of a kind right now,” McDonald Observatory director Taft Armandroff said. “It’s going to allow us to study a lot of areas of astronomy that are on the cutting edge.”

The Observatory received funding from the State of Texas, other universities and private donors to add four new instruments to the telescope along with expanding its view and depth. Two of these instruments, high and low resolution spectrographs, will be used to study the light from both galaxies and individual stars, Armandroff said.

Another new instrument allows the telescope to see high red-shift galaxies, or galaxies that are 10 to 12 billion light years away and were formed shortly after the Big Bang, Armandroff said.

Finally, Armandroff said the telescope now has a habitable zone planet finder which detects wobbles in the movement of a star to see if it has any orbiting planets.

Together, these devices will help astronomers at the University and elsewhere create a 3-D map they can use to measure how fast the universe’s expansion is accelerating and thereby give them an idea as to what force might be causing it, astrophysics professor Karl Gebhardt said.

“It’s crazy exciting. No one has looked at the universe in this way in the past,” Gebhardt said. “We may redefine what gravity actually is, (or dark energy) could be something like a new type of particle.”

Already, students at the University are analysing the data the telescope collects each night. After nightfall in West Texas, the telescope collects information that is sent to a server that both undergraduate and graduate students have access to.

After a class with Gebhardt last semester, aerospace engineering senior Jamie McCullough began working with the McDonald Observatory data. Most of the time, McCullough analyses the data sent over to adjust the information based on how much light was hitting the telescope. McCullough has also been working on writing a code that will perform these calibrations automatically.

“The upgrade is fantastic, and there’s so much data coming off of it, and there’s so much potential for so much advancement,” McCullough said. “It’ll really just be exciting to see what comes of it.”

19 Apr 2017

NASA Radar Spots Relatively Large Asteroid Prior to Flyby

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Radar images of asteroid 2014 JO25 were obtained in the early morning hours on Tuesday, with NASA's 70-meter (230-foot) antenna at the Goldstone Deep Space Communications Complex in California. The images reveal a peanut-shaped asteroid that rotates about once every five hours. The images have resolutions as fine as 25 feet (7.5 meters) per pixel.

Asteroid 2014 JO25 was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona -- a project of NASA's Near-Earth Objects Observations Program in collaboration with the University of Arizona. The asteroid will fly safely past Earth on Wednesday at a distance of about 1.1 million miles (1.8 million kilometres), or about 4.6 times the distance from Earth to the moon. The encounter is the closest the object will have come to Earth in 400 years and will be its closest approach for at least the next 500 years.

"The asteroid has a contact binary structure - two lobes connected by a neck-like region," said Shantanu Naidu, a scientist from NASA's Jet Propulsion Laboratory in Pasadena, California, who led the Goldstone observations. "The images show flat facets, concavities and angular topography."

The largest of the asteroid's two lobes is estimated to be 2,000 feet (620 meters) across.

Radar observations of the asteroid also have been conducted at the National Science Foundation's Arecibo Observatory in Puerto Rico. Additional radar observations are being conducted at both Goldstone and Arecibo on April 19 20, and 21, and could provide images with even higher resolution.

Radar has been used to observe hundreds of asteroids. When these small, natural remnants of the formation of the solar system pass relatively close to Earth, deep space radar is a powerful technique for studying their sizes, shapes, rotation, surface features, and roughness, and for more precise determination of their orbital path.

NASA's Jet Propulsion Laboratory, Pasadena, California, manages and operates NASA's Deep Space Network, including the Goldstone Solar System Radar, and hosts the Center for Near-Earth Object Studies for NASA's Near-Earth Object Observations Program within the agency's Science Mission Directorate.

18 Apr 2017

Do Meteors Hiss, Sizzle, and Pop?

imageFor hundreds of years there have been reports of people hearing the sound of meteors—shooting stars—as they streak across the sky. As early as 1714, astronomy Edmond Halley (yes, that Halley, of comet fame) dismissed these accounts of hissing, sizzling, and popping as figments of the imagination. After all, sound travels much more slowly than light—see: every thunderstorm ever—so any sound from the meteor breaking up in the atmosphere would arrive long after the streak of ionized gas has faded from the sky. But hearing and seeing a meteor at the same time is not a scientific impossibility. A new hypothesis published in Geophysical Research Letters might explain just how it happens, and why the described noises sound a lot like radio static.

When a meteor hits the atmosphere, at between 25,000 and 160,000 miles per hour, it releases electromagnetic radiation, including both light and what are known as very low frequency radio waves. Twenty-five years ago, scientists demonstrated that these waves, which travel just as fast as light, can cause objects, especially metal ones, to vibrate in a way that produces sound.

“The conversion from electromagnetic waves to sound waves … is exactly how your radio works,” Colin Price of Tel Aviv University, co-author of the new study, told Science. The study proposes that these waves come from an electrical current generated as the meteor interacts with the atmosphere. Though it involves coma ions, an am bipolar electric field, and Hall current, it’s the simplest explanation for the phenomenon yet.

Telescope project makes progress on radio-quiet zone

untitledThe Square Kilometre Array (SKA) SA project office has acquired half of the land it needs to create a radio-quiet zone around the large radio telescope and is on track to complete the process by the end of 2018, says spokesman Lorenzo Raynard.

It is an important milestone in a sensitive process as, if the farmers in the area refuse to sell their land, the government can expropriate it. The SKA is an international science project located in SA and Australia and will be the world’s most powerful radio telescope once completed. The South African core is 90km from Carnarvon in the Northern Cape.

About 131,500ha of land surrounding the telescope’s 176-dish core needs to be free from radio-frequency interference. The project acquired 13,500ha of this land in 2008. In 2016 it embarked on a process to acquire another 118,000ha comprising 36 parcels of land close to the core as well as access rights to servitudes that will hold another 21 dishes.

The SKA SA project office has acquired 14 parcels of land, comprising 61,000ha and needs to buy another 18 parcels of land totalling 57,000ha. Four parcels of land originally earmarked for purchase no longer needed to be bought, but would provide access rights to servitudes, said Raynard. The land-acquisition project is one of three SKA processes under way in SA. The Department of Science and Technology has been driving the implementation of legislation to protect the site from radio interference.

17 Apr 2017

Why Sending Stephen Hawking to Space Matters

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Despite having been told he would not make it past his 25th birthday, now 75-year-old renowned cosmologist and science author Stephen Hawking is being sent to space on billionaire Richard Branson’s Virgin Galactic ship. While confined to a wheelchair and communicating via a speech generator attached to a single cheek muscle, Stephen Hawking continues to contribute to the advancement of science in incredible ways. Over the course of his career, Hawking has also been a fierce advocate of disability rights and has shattered the glass ceiling of what people with disabilities are perceived to be capable of time and time again.

While the physical and intellectual capabilities of human beings differ greatly, they do not necessarily define us nor do they render us incapable of accomplishing significant feats. Stephen Hawking has visited one of Earth’s last thresholds, Antarctica, and has experienced weightlessness on a sub-orbital space flight. He is the Director of Research at the Centre for Theoretical Cosmology at the University of Cambridge and has written several novels, of which A Brief History of Time was a record-breaking best-seller. The physicist famously theorized that black holes emit radiation and is a recipient of the Presidential Medal of Freedom, the greatest award for civilians available in the United States. These are just a few of his accomplishments.

Hawking’s incredible career signifies the extent to which the empowerment of people with disabilities through increased accessibility and technological advancement can provide greater opportunities for everyone to pursue their dreams regardless of their circumstances. At age 21, Hawking was diagnosed with a rare early-onset form of amyotrophic lateral sclerosis (ALS) that has slowly paralyzed him. While this disease is generally fatal within five years, Hawking has lived more than five decades since his initial diagnosis. While not everyone diagnosed with ALS may have access to the same treatment and care as this academic celebrity, the longevity and success of Hawking’s career demonstrates that investing in people with disabilities is a worthy pursuit.

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While Stephen Hawking’s physical capabilities have continued to decline over the decades, his mind and intellect have remained intact. By providing Hawking with a vehicle to communicate his brilliance, the pursuit of science has benefited as a whole. People with disabilities are often erased in both science and science fiction. Becoming a spacefaring species was one of the greatest defining moments for human beings. Now, we look to colonizing other terrestrial bodies in the event that one day our own planet can no longer harbour life.

In a visit to London’ Space Museum in 2015, Stephen Hawking stated that space travel “represents an important life insurance for our future survival, as it could prevent the disappearance of humanity by colonizing other planets.” One of the cosmologist’s biggest dreams has been to travel to space himself which will, in the near future, become a reality. As an icon for disability rights activism, Hawking’s journey will allow people with disabilities to see themselves represented in the voyage to the stars.

In science fiction, writers imagine future worlds in which anything is possible. In these imaginings of tomorrow, be they utopian, dystopian or complex, nuanced worlds with problems like our own, disability is often perceived as something to be cured, fixed or erased altogether. In pathologizing disability or removing it entirely from futurist contexts, people with disabilities often do not find themselves represented or as fitting into the grand scheme. As a result, Stephen Hawking’s projected spaceflight matters immensely as it exemplifies that he, like anyone else, is an individual with his own physical and intellectual capacities, of which having a disability is not his sole-defining characteristic.

It is evident that Hawking’s career has been greatly empowered due to his intelligence and access to economic capital which others with his disease may not be as fortunate to have. However, he is a shining example of the potential that can be realized when society works to develop technology and increase accessibility for everyone. Today, accessibility can take on the form of ensuring all stations on public transit lines have elevators or that all new buildings use levers instead of door knobs. The shift towards accessibility in urban planning and the design of all things means that people with disabilities have a bright future ahead.

The rise of space tourism by private companies like Virgin Galactic and SpaceX are disrupting the entire space exploration industry. The CEO of SpaceX, founder of PayPal and Tesla Motors’ Elon Musk has launched private vehicles into space and enabled them to return to Earth with reusable rockets. In doing so, Musk has greatly reduced the cost of spaceflight and in turn made it more accessible. As these companies continue to develop space technology, the goal of taking humans to other planets becomes more realistic. Not only this but also sending human beings to space from all walks of life including those, like Stephen Hawking, with disabilities.

Stephen Hawking being sent so space matters for every dreamer who has imagined themselves leaving Earth to gaze down in wonder upon the curvature of the pale blue dot. It has traditionally only been astronauts with unparalleled physical and intellectual ability who have had the enormous privilege of leaving our planet’s atmosphere. Now, the extremely wealthy can purchase a ticket to the stars via private space travel companies. However, as evidenced by this change and while it may take centuries, it is only a matter of time before space travel becomes available to everyone.

Supermassive black holes found in two tiny galaxies

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Three years ago, a University of Utah-led team discovered that an ultra-compact dwarf galaxy contained a supermassive black hole, then the smallest known galaxy to harbour such a giant black hole. The findings suggested that the dwarfs were likely tiny leftovers of larger galaxies that were stripped of their outer layers after colliding into other, larger galaxies.

Now, the same group of U astronomers and colleagues have found two more ultra-compact dwarf galaxies with supermassive black holes. Together, the three examples suggest that black holes lurk at the centre of most of these objects, potentially doubling the number of supermassive black holes known in the universe. The black holes make up a high percentage of the compact galaxies' total mass, supporting the theory that the dwarfs are remnants of massive galaxies that were ripped apart by larger galaxies.

"We still don't fully understand how galaxies form and evolve over time. These objects can tell us how galaxies merge and collide," says Chris Ahn, doctoral candidate in the Department of Physics & Astronomy, and lead author of the international study that published Monday in The Astrophysical Journal. "Maybe a fraction of the centres of all galaxies are actually these compact galaxies stripped of their outer parts."

Measuring galaxies
 
The authors measured two ultra-compact dwarf galaxies, named VUCD3 and M59cO, that lie far beyond the spiral arms of our Milky Way, orbiting massive galaxies in the Virgo galaxy cluster. They detected a supermassive black hole in both galaxies; VUCD3's black hole has a mass equivalent to 4.4 million suns, making up about 13 percent of the galaxy's total mass, and M59cO's black hole has a mass of 5.8 million suns, making up about 18 percent of its total mass.

By comparison, the monstrous black hole at the centre of the Milky Way has a mass of 4 million suns, but makes up less than .01 percent of the galaxy's total mass.

"It's pretty amazing when you really think about it. These ultra-compact dwarfs are around 0.1 percent the size of the Milky Way, yet they host supermassive black holes that are bigger than the black hole at the centre of our own galaxy," marvels Ahn.

To calculate the ultra-compact dwarf galaxies' mass, the astronomers measured the movement of the stars using the Gemini North telescope located on Mauna Kea volcano in Hawaii. The astronomers have to correct for the distortions caused by Earth's atmosphere. They shot a laser into the sky to make a fake little star, and moved a mirror around hundreds of times a second to undo the distortion. They then applied the technique to the ultra-compact dwarf galaxies, which are so small that the corrections are necessary to measure the motions inside the object. The technique, known as adaptive optics, brings the once blurry galaxy into focus.

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They also analysed images from the Hubble Space Telescope to measure the distribution of the stars in each galaxy, and created a computer simulation that best fit their observations.

They found that the motion of the stars at the centre of the galaxies moved much faster than those on the outside, a classic signature of a black hole. VUCD3 and M59cO are the second and third ultra-compact dwarf galaxies found to contain a supermassive black hole, suggesting that all such dwarfs may harbour similarly massive light-sucking objects.

Ultra-compact dwarf galaxy mysteries
 
Astronomers discovered ultra-compact dwarf galaxies in the late 1990s. The objects are made up of hundreds of millions of stars densely packed together on an average of 100 light years across. Scientists took measurements to see what was happening inside the galaxies, and something didn't add up; the ultra-compact dwarf galaxies had more mass than their stars alone could account for. Senior author Anil Seth, assistant professor in the Department of Physics & Astronomy at the U, led the 2014 study that found the first ultra-compact dwarf galaxy with a supermassive black hole. The two U-led studies make a strong case that supermassive black holes at the centre of the galaxies are responsible for the extra mass.

An alternate theory of the dwarfs is that they are just really massive star clusters -- groups of a hundred thousand stars born at the same time. The largest star cluster in the Milky Way is three million stars, and ultra-compact dwarf galaxies are 10 to 100 times bigger than that. "The question was, 'Is that because they form bigger star clusters with the same process? Or are they different in some way?' This work shows that they are different," Seth continues.

"It's obvious in retrospect, because the centre of a regular galaxy looks almost exactly like these objects, but that wasn't what most people thought they were. I wasn't convinced that we were going to find a black hole when I took the observations," says Seth. "This is a cool example of scientific discovery and how quickly you can reorient our understanding of the universe."

Black holes and the formation of galaxies
 
Black holes are areas with such strong gravity that not even light can escape. They form when stars collapse, leaving behind a black hole with dense mass that exerts gravitational force on the objects around it. Supermassive black holes have a mass of more than 1 million suns, and are thought to be at the centre of all big galaxies.

One explanation for the supermassive black hole inside the ultra-compact dwarf galaxies is that the galaxies were once made up of billions of stars. The authors believe that the dwarfs were "swallowed up" and ripped apart by the gravity of much larger galaxies. The ultra-compact dwarf black hole is the remnant of its formerly massive size. The findings change the way that astronomers can piece together how galaxies form and evolve over time.

"We know that galaxies merge and combine all the time -- that's how galaxies evolve. Our Milky Way is eating up galaxies as we speak," says Seth. "Our general picture of how galaxies form is that little galaxies merge to form big galaxies. But we have a really incomplete picture of that. The ultra-compact dwarf galaxies provide us a longer timeline to be able to look at what's happened in the past."