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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

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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

December 1, 2011 Leave a comment

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