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Mapping The Universe In 3-D

October 17, 2012 Leave a comment

Combining observations from Mauna Kea with data taken by telescopes in space, astronomers at the Institute for Astronomy (University of Hawaii at Manoa) and their collaborators have developed a technique that allows them to map collisions of giant galaxy clusters in three dimensions.

“Being unable to see these large-scale structures from different angles makes it very difficult to figure out their three-dimensional shapes, let alone their relative motions and interactions,” explains Harald Ebeling, IfA astronomer and an expert on galaxy clusters. “All we see in our images is a 2-D projection of a 3-D structure onto the plane of the sky.”

Luckily, when two galaxy clusters collide, astronomers can make use of a clever combination of observations to make the invisible visible. In three recent studies, Ebeling and an international team of collaborators created 3-D models of merging galaxy clusters. Creating these models requires mapping all the components of a cluster: the galaxies that we see in visible light, the hot gas permeating the cluster that emits X-rays, and the invisible dark matter that can be detected only because its gravity distorts the images of objects behind the cluster.

Full Story: http://www.ifa.hawaii.edu/info/press-releases/3-D_Universe/

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What’s Baking On Titan?

October 17, 2012 Leave a comment

Image of a feature shaped like a hot cross bun in the northern region of Titan. Image Credit: NASA/JPL-Caltech/ASI

Radar images from NASA’s Cassini spacecraft reveal some new curiosities on the surface of Saturn’s mysterious moon Titan, including a nearly circular feature that resembles a giant hot cross bun and shorelines of ancient seas. The results were presented today (Oct. 16, 2012) at the American Astronomical Society’s Division of Planetary Sciences conference in Reno, Nev.

Steam from baking often causes the top of bread to lift and crack. Scientists think some similar process involving heat may be at play on Titan. The image showing the bun-like mound was obtained on May 22, 2012, by Cassini’s radar instrument. Scientists have seen similar terrain on Venus, where a dome-shaped region about 20 miles (30 kilometers) across has been seen at the summit of a large volcano called Kunapipi Mons. They theorize that the Titan cross, which is about 40 miles (70 kilometers) long, is also the result of fractures caused by uplift from below, possibly the result of rising magma.

“The ‘hot cross bun’ is a type of feature we have not seen before on Titan, showing that Titan keeps surprising us even after eight years of observations from Cassini,” said Rosaly Lopes, a Cassini radar team scientist based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The ‘bun’ may be the result of what is known on Earth as a laccolith, an intrusion formed by magma pushing up from below. The Henry Mountains of Utah are well-known examples of this geologic phenomenon.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-326

NASA Jet Propulsion Laboratory Selects UT Austin As Research And Education Partner

October 17, 2012 Leave a comment

The NASA Jet Propulsion Laboratory has selected The University of Texas at Austin for its Strategic University Research Partnership program — a federally funded program focused on advancing space exploration.

The partnership will enable the university and JPL researchers to propose collaborative research and educational projects in strategic focus areas such as robotics, nanosatellites and high-precision mapping. The program also creates an employment pipeline for JPL’s future workforce.

The University of Texas at Austin is one of 12 universities that have been selected for this partnership.

Full Story: http://www.engr.utexas.edu/news/7417-nasapartnership

Dark Matter Filament Studied In 3D For The First Time

October 17, 2012 Leave a comment

Hubble image of MACS J0717 with mass overlay. Credit: NASA, ESA, Harald Ebeling (University of Hawaii at Manoa) & Jean-Paul Kneib (LAM)

Astronomers using the NASA/ESA Hubble Space Telescope have studied a giant filament of dark matter in 3D for the first time. Extending 60 million light-years from one of the most massive galaxy clusters known, the filament is part of the cosmic web that constitutes the large-scale structure of the Universe, and is a leftover of the very first moments after the Big Bang. If the high mass measured for the filament is representative of the rest of the Universe, then these structures may contain more than half of all the mass in the Universe.

The theory of the Big Bang predicts that variations in the density of matter in the very first moments of the Universe led the bulk of the matter in the cosmos to condense into a web of tangled filaments. This view is supported by computer simulations of cosmic evolution, which suggest that the Universe is structured like a web, with long filaments that connect to each other at the locations of massive galaxy clusters. However, these filaments, although vast, are made mainly of dark matter, which is incredibly difficult to observe.

The first convincing identification of a section of one of these filaments was made earlier this year. Now a team of astronomers has gone further by probing a filament’s structure in three dimensions. Seeing a filament in 3D eliminates many of the pitfalls that come from studying the flat image of such a structure.

Full Story: http://www.spacetelescope.org/news/heic1215/

Monitoring Io’s Insane Volcanic Activity From The Comfort Of Earth

October 17, 2012 Leave a comment

Watching active volcanic eruptions should definitely be done from a distance, but a group of California researchers has figured out how to do it from the comfort of home. Using an ingenious combination of Earth-based telescopic surveys and archival data, they have gathered nearly 40 distinct snapshots of effusive volcanic eruptions and high temperature outbursts on Jupiter’s tiny moon, Io, showing details as small as 100 km (60 miles) on the moon’s surface.

Io, the innermost moon of Jupiter, is an insanely active volcanic wonderland. Although the most detailed observations have come from spacecraft, the Galileo Jupiter orbiter mission ended in 2003 and no future mission capable of studying Io is planned until, at the earliest, 2030. However, there will be no large gap in the monitoring of Io’s volcanoes, thanks to the efforts of teams like that led by Franck Marchis, a researcher at the Carl Sagan Center of the SETI Institute. Marchis will present results from ground-based telescopic monitoring of volcanic activity on Io over the past decade at the 2012 DPS Meeting in Reno, Nevada.

Full Story: http://www.seti.org/node/1457

New Model Reconciles The Moon’s Earth-Like Composition With The Giant Impact Theory Of Formation

October 17, 2012 Leave a comment

The giant impact believed to have formed the Earth-Moon system has long been accepted as canon. However, a major challenge to the theory has been that the Earth and Moon have identical oxygen isotope compositions, even though earlier impact models indicated they should differ substantially. In a paper published today in the journal Science online, a new model by Southwest Research Institute (SwRI), motivated by accompanying work by others on the early dynamical history of the Moon, accounts for this similarity in composition while also yielding an appropriate mass for Earth and Moon.

In the giant impact scenario, the Moon forms from debris ejected into an Earth-orbiting disk by the collision of a smaller proto-planet with the early Earth. Earlier models found that most or much of the disk material would have originated from the Mars-sized impacting body, whose composition likely would have differed substantially from that of Earth.

The new models developed by Dr. Robin M. Canup, an associate vice president in the SwRI Space Science and Engineering Division, and funded by the NASA Lunar Science Institute, involve much larger impactors than were previously considered. In the new simulations, both the impactor and the target are of comparable mass, with each containing about 4 to 5 times the mass of Mars. The near symmetry of the collision causes the disk’s composition to be extremely similar to that of the final planet’s mantle over a relatively broad range of impact angles and speeds, consistent with the Earth-Moon compositional similarities.

Full Story: http://www.swri.org/9what/releases/2012/earth-moon-impact.htm
Also: http://www.fas.harvard.edu/~planets/sstewart/Moon.html
Also: https://news.wustl.edu/news/Pages/24148.aspx

NASA’s WISE Colors In Unknowns On Jupiter Asteroids

October 17, 2012 Leave a comment

Scientists using data from NASA’s Wide-field Infrared Survey Explorer, or WISE, have uncovered new clues in the ongoing mystery of the Jovian Trojans — asteroids that orbit the sun on the same path as Jupiter. Like racehorses, the asteroids travel in packs, with one group leading the way in front of the gas giant, and a second group trailing behind.

The observations are the first to get a detailed look at the Trojans’ colors: both the leading and trailing packs are made up of predominantly dark, reddish rocks with a matte, non-reflecting surface. What’s more, the data verify the previous suspicion that the leading pack of Trojans outnumbers the trailing bunch.

The new results offer clues in the puzzle of the asteroids’ origins. Where did the Trojans come from? What are they made of? WISE has shown that the two packs of rocks are strikingly similar and do not harbor any “out-of-towners,” or interlopers, from other parts of the solar system. The Trojans do not resemble the asteroids from the main belt between Mars and Jupiter, nor the Kuiper belt family of objects from the icier, outer regions near Pluto.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-322