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Strange New ‘Species’ of Ultra-Red Galaxy Discovered

December 1, 2011 Leave a comment

Credit: David A. Aguilar (CfA)

Credit: David A. Aguilar (CfA)

In the distant reaches of the universe, almost 13 billion light-years from Earth, a strange species of galaxy lay hidden. Cloaked in dust and dimmed by the intervening distance, even the Hubble Space Telescope couldn’t spy it. It took the revealing power of NASA’s Spitzer Space Telescope to uncover not one, but four remarkably red galaxies. And while astronomers can describe the members of this new “species,” they can’t explain what makes them so ruddy.

“We’ve had to go to extremes to get the models to match our observations,” said Jiasheng Huang of the Harvard-Smithsonian Center for Astrophysics (CfA). Huang is lead author on the paper announcing the find, which was published online by theAstrophysical Journal.

Spitzer succeeded where Hubble failed because Spitzer is sensitive to infrared light – light so red that it lies beyond the visible part of the spectrum. The newfound galaxies are more than 60 times brighter in the infrared than they are at the reddest colors Hubble can detect.

Full Story: http://www.cfa.harvard.edu/news/2011/pr201133.html

Mars Mission Hoping to Satisfy Curiosity

December 1, 2011 Leave a comment

The University of Leicester is to play a key role in NASA’s $2.5 billion mission to Mars.

Dr John Bridges of the University’s Space Research Centre, leads a team from the University of Leicester, the Open University and CNES France which have been accepted as participating scientists on the Mars Science Laboratory Mission, which lands in August 2012.

John Bridges will be among the first people to study images returned after landing, to determine the conditions associated with the presence of water. The Leicester-led team will focus on determining the conditions associated with the presence of water in past epochs at the landing site.

Launched on 26th November, the Mars Science Laboratory (MSL) is a NASA mission with the aim to land and operate a rover named Curiosity on the surface of Mars.

Full Story: http://www2.le.ac.uk/offices/press/press-releases/2011/december/mars-mission-hoping-to-satisfy-curiousity

UK Instrument to Fly on India’s First Astronomy Mission

December 1, 2011 Leave a comment

Highly specialised equipment constructed at the University of Leicester for India’s first national astronomy satellite- Astrosat – is to be handed over to a delegation from India in December.

On 5th December 2011, the University of Leicester will host an event to celebrate the final visit by a team from the Tata Institute for Fundamental Research, (TIFR), Mumbai, as they test one of the final pieces for Astrosat – scheduled to launch in 2012.

The five instruments in Astrosat’s payload will observe exotic objects and phenomena such as black holes, neutron stars, and active galaxies at a number of different wavelengths simultaneously, from the ultraviolet band to energetic x-rays. Each of its five instruments is looking at different regions of the electromagnetic spectrum which allows simultaneous measurements to be taken across a wide range of energies.

Full Story: http://www2.le.ac.uk/offices/press/press-releases/2011/december/leicester-set-to-fly-high-in-indias-first-ever-national-astronomy-mission

Stars Have Found a New Way to Die

December 1, 2011 Leave a comment

Gamma-ray bursts (GRBs) are brief and intense flashes of gamma-ray radiation that can occur randomly from any direction of the sky. They are so powerful that a single such event can be as luminous as all the visible stars in the sky, but just for a few seconds. They were discovered first during the cold war, when the USA were busy verifying the Nuclear Test Ban Treaty, since for those primitive detectors, GRBs had properties akin to those of the atmospheric atomic explosions. Fortunately, our atmosphere is opaque to gamma rays, which has allowed preserving life on the Earth. But this remarkable property has as a counterpart that GRBs can only be detected by instruments on board of spacecrafts such as NASA’s Swift satellite.

Swift localizes GRBs and distributes their coordinates to astronomers all over the world, who can follow up these explosive events using ground-based telescopes. These observations have shown that GRBs are accompanied by fading emissions from ultraviolet to radio wavelengths, the so-called “afterglow”. This afterglow emission is usually produced by synchrotron radiation emitted by charged particles (mostly electrons and positrons) moving in magnetic fields at ultra-relativistic speeds: velocities above 99.9999% of the speed of light (note that differently from the fractious neutrinos from Gran Sasso, these particles are subluminal).

On Christmas Day 2010 a very peculiar GRB occurred, designated GRB101225A according to the date of its discovery, also nicknamed “the Christmas Burst”. It lasted more than half an hour and, in addition to its extraordinary duration (typically GRBs last a few seconds), it promptly attracted scientists’ attention for the fact that the spectrum displayed a thermal contribution (like a classical blackbody) unusually powerful. Indeed, the thermal component was so powerful that it dominates completely the X-ray-to-ultraviolet emission of this object, challenging the long-standing paradigm that GRB afterglows are produced by non-thermal emission processes (like synchrotron).

Full Story: http://astronews.us/2011-12-01-1313.html

How Did Martian Polar Gullies Form?

December 1, 2011 Leave a comment

Gullies on Mars have been pointed to as evidence for the presence of flowing liquid water. However, gullies also exist in Mars’ polar regions, where temperatures are too low to support liquid water. Other processes have been proposed to explain the origin of gullies but have not been confirmed. For instance, sediment lying on top of a seasonal accumulation of carbon dioxide frost could flow like a fluid if the frost sublimes (turns to gas directly from the solid stage) sufficiently quickly. This fluidized sediment could form gullies.

To determine whether conditions are suitable for such fluidization to occur in Mars’ polar regions, Cedillo-Flores et al. calculated the carbon dioxide sublimation rate needed to fluidize sand and dust lying on top of the carbon dioxide frost. They then used a thermal model of Mars’ surface and subsurface to determine whether buried carbon dioxide frost could potentially sublimate at that rate. The researchers confirm that sediment fluidization could indeed occur in Mars’ polar regions, and thus, Martian gullies can form without the
presence of liquid water.

Source: Geophysical Research Letters, doi:10.1029/2011GL049403, 2011
http://dx.doi.org/10.1029/2011GL049403

Title: CO2 gas fluidization in the initiation and formation of Martian polar gullies

Authors: Yolanda Cedillo-Flores: Facultad de Filosofia y Letras, Universidad
Nacional Autonoma de Mexico, Mexico City, Mexico and Lunar and Planetary Institute, Houston, Texas, USA;

Allan H. Treiman: Lunar and Planetary Institute, Houston, Texas, USA;

Jeremie Lasue: Lunar and Planetary Institute, Houston, Texas, USA and Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA;

Stephen M. Clifford: Lunar and Planetary Institute, Houston, Texas, USA.

Categories: Astronomy, Mars, Solar System Tags: , ,

2012: Magnetic Pole Reversal Happens All The (Geologic) Time

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Scientists understand that Earth’s magnetic field has flipped its polarity many times over the millennia. In other words, if you were alive about 800,000 years ago, and facing what we call north with a magnetic compass in your hand, the needle would point to ‘south.’ This is because a magnetic compass is calibrated based on Earth’s poles. The N-S markings of a compass would be 180 degrees wrong if the polarity of today’s magnetic field were reversed. Many doomsday theorists have tried to take this natural geological occurrence and suggest it could lead to Earth’s destruction. But would there be any dramatic effects? The answer, from the geologic and fossil records we have from hundreds of past magnetic polarity reversals, seems to be ‘no.’

Reversals are the rule, not the exception. Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 to 300,000 years, although it has been more than twice that long since the last reversal. A reversal happens over hundreds or thousands of years, and it is not exactly a clean back flip. Magnetic fields morph and push and pull at one another, with multiple poles emerging at odd latitudes throughout the process. Scientists estimate reversals have happened at least hundreds of times over the past three billion years. And while reversals have happened more frequently in “recent” years, when dinosaurs walked Earth a reversal was more likely to happen only about every one million years.

Full Story: http://www.nasa.gov/topics/earth/features/2012-poleReversal.html

Cosmic Explosion Explained Just in Time for Christmas

December 1, 2011 Leave a comment

Credit: A. Simonnet, NASA, E/PO, Sonoma State University

Credit: A. Simonnet, NASA, E/PO, Sonoma State University

An explosion far across the universe rattled astronomers last year on Christmas Day. Called a gamma-ray burst (GRB), it incited a flurry of activity from telescopes in space and on the ground, including the 2.1-meter Otto Struve Telescope at The University of Texas at Austin’s McDonald Observatory. This year, just in time for Christmas, astronomers say they now know what happened — and it requires a new model for the origin of at least some GRBs.

Their research, led by Christina Thöne of Spain’s Instituto de Astrofisica de
Andalucia, appears in tomorrow’s issue of the journal Nature.

Full Story: http://mcdonaldobservatory.org/news/releases/2011/1130.html

Scientists Make Key Discovery About the Atmosphere of Early Earth

December 1, 2011 Leave a comment

Scientists in the New York Center for Astrobiology at Rensselaer Polytechnic Institute have used the oldest minerals on Earth to reconstruct the atmospheric conditions present on Earth very soon after its birth. The findings, which appear in the Dec. 1 edition of the journal Nature, are the first direct evidence of what the ancient atmosphere of the planet was like soon after its formation and directly challenge years of research on the type of atmosphere out of which life arose on the planet.

The scientists show that the atmosphere of Earth just 500 million years after its creation was not a methane-filled wasteland as previously proposed, but instead was much closer to the conditions of our current atmosphere. The findings, in a paper titled “The oxidation state of Hadean magmas and implications for early Earth’s atmosphere,” have implications for our understanding of how and when life began on this planet and could begin elsewhere in the universe. The research was funded by NASA.

For decades, scientists believed that the atmosphere of early Earth was highly reduced, meaning that oxygen was greatly limited. Such oxygen-poor conditions would have resulted in an atmosphere filled with noxious methane, carbon monoxide, hydrogen sulfide, and ammonia. To date, there remain widely held theories and studies of how life on Earth may have been built out of this deadly atmosphere cocktail

Full Story: http://news.rpi.edu/update.do?artcenterkey=2953&setappvar=page%281%29

Astronomers Hunt Star’s ‘Signal of Impending Doom’

December 1, 2011 Leave a comment

An otherwise nondescript binary star system in the Whirlpool Galaxy has brought astronomers tantalizingly close to their goal of observing a star just before it goes supernova.

The study, submitted in a paper to the Astrophysical Journal, provides the latest result from an Ohio State University galaxy survey underway with the Large Binocular Telescope, located in Arizona.

In the first survey of its kind, the researchers have been scanning 25 nearby galaxies for stars that brighten and dim in unusual ways, in order to catch a few that are about to meet their end. In the three years since the study began, this particular unnamed binary system in the Whirlpool Galaxy was the first among the stars they’ve cataloged to produce a supernova.

Full Story: http://researchnews.osu.edu/archive/deathstar.htm

NASA’s Swift Finds a Gamma-Ray Burst With a Dual Personality

December 1, 2011 Leave a comment

A peculiar cosmic explosion first detected by NASA’s Swift observatory on Christmas Day 2010 was caused either by a novel type of supernova located billions of light-years away or an unusual collision much closer to home, within our own galaxy. Papers describing both interpretations appear in the Dec. 1 issue of the journal Nature.

Gamma-ray bursts (GRBs) are the universe’s most luminous explosions, emitting more energy in a few seconds than our sun will during its entire energy-producing lifetime. What astronomers are calling the “Christmas burst” is so unusual that it can be modeled in such radically different ways.

“What the Christmas burst seems to be telling us is that the family of gamma-ray bursts is more diverse than we fully appreciate,” said Christina Thoene, the supernova study’s lead author, at the Institute of Astrophysics of Andalusia in Granada, Spain. It’s only by rapidly detecting hundreds of them, as Swift is doing, that we can catch some of the more eccentric siblings.”

Full Story: http://www.nasa.gov/mission_pages/swift/bursts/dual-burst.html