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Archive for August, 2013

Ultracold Big Bang Experiment Successfully Simulates Evolution Of Early Universe

August 29, 2013 Leave a comment

Physicists have reproduced a pattern resembling the cosmic microwave background radiation in a laboratory simulation of the Big Bang, using ultracold cesium atoms in a vacuum chamber at the University of Chicago.

“This is the first time an experiment like this has simulated the evolution of structure in the early universe,” said Cheng Chin, professor in physics. Chin and his associates reported their feat in the Aug. 1 edition of Science Express, and it will appear soon in the print edition of Science.

Full Story: http://news.uchicago.edu/article/2013/08/28/ultracold-big-bang-experiment-successfully-simulates-evolution-early-universe

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NASA’s Chandra Observatory Catches Giant Black Hole Rejecting Material

August 29, 2013 Leave a comment

Astronomers using NASA’s Chandra X-ray Observatory have taken a major step in explaining why material around the giant black hole at the center of the Milky Way Galaxy is extraordinarily faint in X-rays. This discovery holds important implications for understanding black holes.

New Chandra images of Sagittarius A* (Sgr A*), which is located about 26,000 light-years from Earth, indicate that less than 1 percent of the gas initially within Sgr A*’s gravitational grasp ever reaches the point of no return, also called the event horizon. Instead, much of the gas is ejected before it gets near the event horizon and has a chance to brighten, leading to feeble X-ray emissions.

These new findings are the result of one of the longest observation campaigns ever performed with Chandra. The spacecraft collected five weeks’ worth of data on Sgr A* in 2012. The researchers used this observation period to capture unusually detailed and sensitive X-ray images and energy signatures of super-heated gas swirling around Sgr A*, whose mass is about 4 million times that of the sun.

Full Story: http://www.nasa.gov/mission_pages/chandra/news/black-hole-rejects-food.html#.UiAD9L-wUV0

Neutron Stars In The Computer Cloud: Einstein@Home Discovers 24 New Pulsars In Archival Data

August 29, 2013 Leave a comment

The combined computing power of 200,000 private PCs helps astronomers take an inventory of the Milky Way. The Einstein@Home project connects home and office PCs of volunteers from around the world to a global supercomputer. Using this computer cloud, an international team lead by scientists from the Max Planck Institutes for Gravitational Physics and for Radio Astronomy analysed archival data from the CSIRO Parkes radio telescope in Australia. Using new search methods, the global computer network discovered 24 pulsars – extraordinary stellar remnants with extreme physical properties. These can be used as testbeds for Einstein’s general theory of relativity and could help to complete our picture of the pulsar population.

“We could only conduct our search thanks to the enormous computing power provided by the Einstein@Home volunteers,” says Benjamin Knispel, researcher at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Hannover, and lead author of the study now published in The Astrophysical Journal. “Through the participation of the public, we discovered 24 new pulsars in our Milky Way, which had previously been missed – and some of them are particularly interesting.”

Full Story: http://www.aei.mpg.de/480062/Einstein_Home_24PSRs_PMPS
Einstein@Home Home Page: http://einstein.phys.uwm.edu

Stanford Solar Scientists Solve One Of The Sun’s Mysteries

August 28, 2013 Leave a comment

Credit: NASA SDO / HMI

Credit: NASA SDO / HMI

Stanford solar scientists have solved one of the few remaining fundamental mysteries of how the sun works.

The mechanism, known as meridional flow, works something like a conveyor belt. Magnetic plasma migrates north to south on the sun’s surface, from the equator to the poles, and then cycles into the sun’s interior on its way back to the equator.

The rate and depth beneath the surface of the sun at which this process occurs is critical for predicting the sun’s magnetic and flare activity, but has remained largely unknown until now.

Full Story: http://news.stanford.edu/pr/2013/pr-solar-magnetic-field-082913.html

New Cassini Data From Titan indicate A Rigid, Weathered Ice Shell

August 28, 2013 Leave a comment

An analysis of gravity and topography data from Saturn’s largest moon, Titan, has revealed unexpected features of the moon’s outer ice shell. The best explanation for the findings, the authors said, is that Titan’s ice shell is rigid and that relatively small topographic features on the surface are associated with large roots extending into the underlying ocean. The study is published in the August 29 issue of the journal Nature.

Led by planetary scientists Douglas Hemingway and Francis Nimmo at the University of California, Santa Cruz, the study used new data from NASA’s Cassini spacecraft. The researchers were surprised to find a negative correlation between the gravity and topography signals on Titan.

“Normally, if you fly over a mountain, you expect to see an increase in gravity due to the extra mass of the mountain. On Titan, when you fly over a mountain the gravity gets lower. That’s a very odd observation,” said Nimmo, a professor of Earth and planetary sciences at UC Santa Cruz.

Full Story: http://news.ucsc.edu/2013/08/titan-ice-shell.html

New Mexican Skies Protected With Dark Sky Park Designation

August 28, 2013 Leave a comment

"Milky Way, Fajada Butte" by Stan Honda

“Milky Way, Fajada Butte” by Stan Honda

The 34,000-acre Chaco Culture National Historical Park is home to many ancient wonders including the remains of a civilization that thrived over 1,000 years ago. The park, which has been protecting its archaeological riches since it was established in 1907, is now protecting its views of the starry skies too. It has just been named as the International Dark-Sky Associationʼs newest Dark Sky Park.

“Once the night sky was something that was very much a part of the human experience at Chaco and around the globe,” says IDA Executive Director Bob Parks. “We are delighted that Chaco is now preserving the nighttime environment alongside their historic treasures.”

As a Gold-tier IDA Dark Sky Park, Chaco has shown its commitment to preserving its near-pristine night skies. The park has adopted a set of strict lighting guidelines that include the use of dark-sky friendly lighting now and in the future, ensuring that it will do its part to keep the nighttime environment natural and unspoiled for generations to come.

Full Story: http://www.darksky.org/night-sky-conservation/338

Oldest Solar Twin Identified

August 28, 2013 Leave a comment

Astronomers have only been observing the Sun with telescopes for 400 years — a tiny fraction of the Sun’s age of 4.6 billion years. It is very hard to study the history and future evolution of our star, but we can do this by hunting for rare stars that are almost exactly like our own, but at different stages of their lives. Now astronomers have identified a star that is essentially an identical twin to our Sun, but 4 billion years older — almost like seeing a real version of the twin paradox in action.

Jorge Melendez (Universidade de São Paulo, Brazil), the leader of the team and co-author of the new paper explains: “For decades, astronomers have been searching for solar twins in order to know our own life-giving Sun better. But very few have been found since the first one was discovered in 1997. We have now obtained superb-quality spectra from the VLT and can scrutinise solar twins with extreme precision, to answer the question of whether the Sun is special.”

Full Story: http://www.eso.org/public/news/eso1337/