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Archive for August 15, 2013

NASA Rover Gets Movie As A Mars Moon Passes Another

August 15, 2013 Leave a comment

The larger of the two moons of Mars, Phobos, passes directly in front of the other, Deimos, in a new series of sky-watching images from NASA’s Mars rover Curiosity.

Large craters on Phobos are clearly visible in these images from the surface of Mars. No previous images from missions on the surface caught one moon eclipsing the other.

Large craters on Phobos are clearly visible in these images from the surface of Mars. No previous images from missions on the surface caught one moon eclipsing the other.

These observations of Phobos and Deimos help researchers make knowledge of the moons’ orbits even more precise.

“The ultimate goal is to improve orbit knowledge enough that we can improve the measurement of the tides Phobos raises on the Martian solid surface, giving knowledge of the Martian interior,” said Mark Lemmon of Texas A&M University, College Station. He is a co-investigator for use of Curiosity’s Mastcam. “We may also get data good enough to detect density variations within Phobos and to determine if Deimos’ orbit is systematically changing.”

Full Story and Video: http://www.jpl.nasa.gov/news/news.php?release=2013-253

Hubble Explores The Origins Of Modern Galaxies

August 15, 2013 Leave a comment

Astronomers have used observations from Hubble’s CANDELS survey to explore the sizes, shapes, and colours of distant galaxies over the last 80% of the Universe’s history. In the Universe today galaxies come in a variety of different forms, and are classified via a system known as the Hubble Sequence — and it turns out that this sequence was already in place as early as 11 billion years ago.

The Hubble Sequence classifies galaxies according to their morphology and star-forming activity, organising them into a cosmic zoo of spiral, elliptical, and irregular shapes with whirling arms, fuzzy haloes and bright central bulges. Two main types of galaxy are identified in this sequence: elliptical and spiral, with a third type, lenticular, settling somewhere between the two.

This accurately describes what we see in the region of space around us, but how does galaxy morphology change as we look further back in time, to when the Universe was very young?

“This is a key question: when and over what timescale did the Hubble Sequence form?” says BoMee Lee of the University of Massachusetts, USA, lead author of a new paper exploring the sequence. “To do this you need to peer at distant galaxies and compare them to their closer relatives, to see if they too can be described in the same way.”

Full Story: http://www.spacetelescope.org/news/heic1315/

NGC 1232: Dwarf Galaxy Caught Ramming Into A Large Spiral

August 15, 2013 Leave a comment

Credit: X-ray: NASA/CXC/Huntingdon Inst. for X-ray Astronomy/G.Garmire, Optical: ESO/VLT

Credit: X-ray: NASA/CXC/Huntingdon Inst. for X-ray Astronomy/G.Garmire, Optical: ESO/VLT

Observations with NASA’s Chandra X-ray Observatory have revealed a massive cloud of multimillion-degree gas in a galaxy about 60 million light years from Earth. The hot gas cloud is likely caused by a collision between a dwarf galaxy and a much larger galaxy called NGC 1232. If confirmed, this discovery would mark the first time such a collision has been detected only in X-rays, and could have implications for understanding how galaxies grow through similar collisions.

An image combining X-rays and optical light shows the scene of this collision. The impact between the dwarf galaxy and the spiral galaxy caused a shock wave – akin to a sonic boom on Earth – that generated hot gas with a temperature of about 6 million degrees. Chandra X-ray data, in purple, show the hot gas has a comet-like appearance, caused by the motion of the dwarf galaxy. Optical data from the European Southern Observatory’s Very Large Telescope reveal the spiral galaxy in blue and white. X-ray point sources have been removed from this image to emphasize the diffuse emission.

Full Story and Images: http://www.chandra.si.edu/photo/2013/ngc1232/