COLUMBUS, Ohio – A study using a unique new instrument on the world’s largest optical telescope has revealed the likely origins of especially bright supernovae that astronomers use as easy-to-spot “mile markers” to measure the expansion and acceleration of the universe.
Piecing together the events of the farthest touchdown a manmade spacecraft has ever made on an alien world reveals new clues about Titan’s surface and helps plan future missions to moons and planets.
The Huygens probe, ferried to Saturn’s moon Titan by NASA’s Cassini spacecraft, bounced, slid and wobbled its way to rest in the 10 seconds after touching down on Titan in January 2005, a new analysis reveals. The moon’s surface is more complex than previously thought.
Scientists reconstructed the chain of events by analyzing data from a variety of instruments that were active during the impact, in particular changes in the acceleration experienced by the probe. The probe was supplied by the European Space Agency and named after the Dutch 17th century astronomer Christiaan Huygens. (more…)
Analysis of data from the National Science Foundation’s South Pole Telescope, for the first time, more precisely defines the period of cosmological evolution when the first stars and galaxies formed and gradually illuminated the universe. The data indicate that this period, called the epoch of reionization, was shorter than theorists speculated — and that it ended early.
“We find that the epoch of reionization lasted less than 500 million years and began when the universe was at least 250 million years old,” said Oliver Zahn, a postdoctoral fellow at the Berkeley Center for Cosmological Physics at the University of California, Berkeley, who led the study. “Before this measurement, scientists believed that reionization lasted 750 million years or longer, and had no evidence as to when reionization began.” (more…)
Astronomers have witnessed for the first time a spiral galaxy in the early universe, billions of years before many other spiral galaxies formed. In findings reported July 19 in the journal Nature, the astronomers said they discovered it while using the Hubble Space Telescope to take pictures of about 300 very distant galaxies in the early universe and to study their properties. This distant spiral galaxy is being observed as it existed roughly three billion years after the Big Bang, and light from this part of the universe has been traveling to Earth for about 10.7 billion years.
“As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric,” said Alice Shapley, a UCLA associate professor of physics and astronomy, and co-author of the study. “The vast majority of old galaxies look like train wrecks. Our first thought was, why is this one so different, and so beautiful?” (more…)
PASADENA, Calif. – Astronomers have gathered the most direct evidence yet of a supermassive black hole shredding a star that wandered too close. NASA’s Galaxy Evolution Explorer, a space-based observatory, and the Pan-STARRS1 telescope on the summit of Haleakala in Hawaii were among the first to help identify the stellar remains.
Supermassive black holes, weighing millions to billions times more than the sun, lurk in the centers of most galaxies. These hefty monsters lie quietly until an unsuspecting victim, such as a star, wanders close enough to get ripped apart by their powerful gravitational clutches. (more…)
ANN ARBOR, Mich.— The fastest wind ever discovered blowing off a disk around a stellar-mass black hole has been observed by a team of astronomers that includes a University of Michigan doctoral student.
Using NASA’s Chandra X-ray Observatory, an orbiting telescope, they clocked the record-breaking super wind at about 20 million mph, or about 3 percent of the speed of light. This is nearly 10 times faster than astronomers had previously observed from a stellar-mass black hole. (more…)
A team led by UCLA research astronomer Michael Rich has used a unique telescope to discover a previously unknown companion to the nearby galaxy NGC 4449, which is some 12.5 million light years from Earth. The newly discovered dwarf galaxy had escaped even the prying eyes of the Hubble Space Telescope.
The research is published Feb. 9 in the journal Nature.(more…)
*In a career that spanned more than half a century, Gehrels fostered new research on asteroids and comets, including those that pose a threat to Earth.*
Tom Gehrels, an internationally noted planetary scientist and astronomer at the University of Arizona, as well as a hero of the Dutch Resistance during WWII, died Monday. He was 86.
Gehrels was among the first members of the fledgling Lunar and Planetary Laboratory when he joined the UA in 1961. During a long and distinguished career Gehrels pioneered new research on asteroids and comets, especially those that pose a collision threat to Earth. He also developed and taught introductory astronomy courses that were popular with non-science undergraduates. (more…)
