astronomer – Page 2 – Shamskm: A site to exchange knowledge and solutions

Bounce, Skid, Wobble: How Huygens Landed on Titan

By Guest PostOctober 11, 2012Science17th century, analysis, astronomer, cassini spacecraft, christiaan huygens, direction, dutch, earth, erich karkoschka, european, evaporate, friction, hazy atmosphere, horizon, huygens data, huygens impact, huygens probe, institute, lower atmosphere, max planck, methane, model, moon, moon surface, motion, mud like, NASA, nicolas altobelli, organic aerosols, ralph lorenz, saturn, space agency, splat, stefan schroder, substance, titan, titan atmosphere, undisturbed terrain

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…)

First Stars, Galaxies Formed more Rapidly than Expected

By Guest PostSeptember 9, 2012Scienceanalysis, anisotropy probe, Antarctica, astronomer, background, Berkeley, california, christian reichardt, cmb, cosmic microwave, cosmological evolution, data, earth axis, electron, Epoch, Galaxy, geographic, herschel satellite, high resolution, hydrogen atom, image, john carlstrom, kavli foundation, microwave, millimeter wavelength, national, neutral, neutral gas, oliver zahn, period, plasma, polar plateau, proton, radiation, reionization, s chandrasekhar, science foundation, south pole, star, telescope, ultraviolet light, universe, university, wilkinson

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…)

Black Hole Caught Red-Handed in a Stellar Homicide

By Guest PostMay 2, 2012Sciencearmin rest, astronomer, Baltimore, billion light years, black hole, chandra, demise, Galaxy, galaxy evolution explorer, haleakala, hawaii, helium gas, johns hopkins university, milky way galaxy, NASA, pan starrs1 telescope, supermassive, suvi gezari

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…)

Fastest Wind From Stellar Mass Black Hole Discovered

By Guest PostFebruary 25, 2012Scienceashley king, astronomer, binary system, black hole, chandra, chandra spectrum, chandra xray observatory, cosmic equivalent, earth, gas, hurricane, igr j17091, igr j17091 3624, iron molecules, jon miller, light years, magnetic fields, material flow, milky way galaxy, molecule, NASA, orbiting telescope, spectrum, speed of light, stars collapse, stellar mass black hole, super wind, supermassive black holes, university of michigan, wind, xrays

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…)

Astronomy Team That Includes UCLA Finance Professor Discovers Nearby Dwarf Galaxy

By Guest PostFebruary 10, 2012Scienceaaron romanowsky, astronomer, big bang, c28 telescope, centurion 28, christine black, david martinez delgado, david reitzel, dwarf galaxy, francis longstaff, frazier park, Galaxy, gravitational attraction, gravitational tug, gravity, griffith observatory, halo population, Hubble Space Telescope, hydrogen gas, james riffle, kern county, light, light years, living fossil, michael rich, Milky Way, milky way galaxy, ngc 4449, night sky, polaris observatory association, r jay gabany, sagittarius dwarf galaxy, sky, star formation, telescope, transient stage

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…)

Astronomers Identify Thick Disc of Older Stars in Nearby Andromeda Galaxy

By Guest PostFebruary 16, 2011Scienceandromeda, andromeda galaxy, astronomer, evolution, formation of the andromeda system, galactic evolution, hawaii, hubble imaging, keck observatory, keck telescope, m31, michael rich, michelle collins, Milky Way, motions, robert gendler, scott chapman, spiral galaxy, spiral structure, thick stellar disc

An international team of astronomers has identified for the first time a thick stellar disc in the Andromeda galaxy, the nearest large spiral galaxy to our own Milky Way.

The discovery of the thick disc, a major result from a five-year investigation, will help astronomers better understand the processes involved in the formation and evolution of large spiral galaxies like ours, according to the team, which includes UCLA research astronomer Michael Rich and colleagues from Europe and Australia. (more…)

Cosmic Curiosity Reveals Ghostly Glow of Dead Quasar

By Guest PostNovember 5, 2010Scienceastronomer, black hole, dead quasar, dutch, Galaxy, galaxy zoo, gas cloud, hanny van arkel, hanny's object, hanny's voorwerp, kevin schawinski, life cycle, light echo, meg urry, paolo coppi, priyamvada natarajan, schoolteacher, yale university

The green Voorwerp in the foreground remains illuminated by light emitted up to 70,000 years ago by a quasar in the center of the background galaxy, which has since died out. Image credit: WIYN/William Keel/Anna Manning

While sorting through hundreds of galaxy images as part of the Galaxy Zoo citizen science project two years ago, Dutch schoolteacher and volunteer astronomer Hanny van Arkel stumbled upon a strange-looking object that baffled professional astronomers. Two years later, a team led by Yale University researchers has discovered that the unique object represents a snapshot in time that reveals surprising clues about the life cycle of black holes.

In a new study, the team has confirmed that the unusual object, known as Hanny’s Voorwerp (Hanny’s “object” in Dutch), is a large cloud of glowing gas illuminated by the light from a quasar-an extremely energetic galaxy with a supermassive black hole at its center. The twist, described online in the Astrophysical Journal Letters, is that the quasar lighting up the gas has since burned out almost entirely, even though the light it emitted in the past continues to travel through space, illuminating the gas cloud and producing a sort of “light echo” of the dead quasar. (more…)

Tag Archives: astronomer