May 15, 2008, 8:29 PM CT

'Super Road Maps' of Planets and Moons

Technology that could someday "MapQuest" Mars and other bodies in the solar system is under development at Rochester Institute of Technology's Rochester Imaging Detector Laboratory (RIDL), in collaboration with Massachusetts Institute of Technology's Lincoln Laboratory.

Three-Dimensional "super roadmaps" of other planets and moons would provide robots, astronauts and engineers details about atmospheric composition, biohazards, wind speed and temperature. Information like this could help land future spacecraft and more effectively navigate roving cameras across a Martian or lunar terrain.

RIT scientist Donald Figer and his team are in the process of developing a new type of detector that uses LIDAR (LIght Detection and Ranging), a technique similar to radar, but which uses light instead of radio waves to measure distances. The project will deliver a new generation of optical/ultraviolet imaging LIDAR detectors that will significantly extend NASA science capabilities for planetary applications by providing 3-D location information for planetary surfaces and a wider range of coverage than the single-pixel detectors currently combined with LIDAR.

The device will consist of a 2-D continuous array of light sensing elements connected to high-speed circuits. The $547,000 NASA-funded program also includes a potential $589,000 phase for fabrication and testing......... Posted by: Sean      Read more         Source

May 14, 2008, 9:00 PM CT

Discovery of most recent supernova in our galaxy

The most recent supernova in our Galaxy has been discovered by tracking the rapid expansion of its remains. This result, using NASA's Chandra X-ray Observatory and NRAO's Very Large Array (VLA), has implications for understanding how often supernovas explode in the Milky Way galaxy.

The supernova explosion occurred about 140 years ago, making it the most recent supernova in the Milky Way as measured in Earth's time frame. Previously, the last known galactic supernova occurred around 1680, based on studying the expansion of its remnant Cassiopeia A.

The recent supernova explosion was not seen in optical light about 140 years ago because it occurred close to the center of the Galaxy, and is embedded in a dense field of gas and dust. This made it about a trillion times fainter, in optical light, than an unobscured supernova. However, the supernova remnant it caused, G1.9+0.3, is now seen in X-ray and radio images.

"We can see some supernova explosions with optical telescopes across half of the Universe, but when they're in this murk we can miss them in our own cosmic backyard," said Stephen Reynolds of North Carolina State University, who led the Chandra study. "Fortunately, the expanding gas cloud from the explosion shines brightly in radio waves and X-rays for thousands of years. X-ray and radio telescopes can see through all that obscuration and show us what we've been missing"......... Posted by: Sean      Read more         Source

May 13, 2008, 7:43 PM CT

$34 Million For U.S. Environmental Satellite

A $34 million solar instrument package to be built by the University of Colorado at Boulder, considered a crucial tool to help monitor global climate change, has been restored to a U.S. government satellite mission slated for launch in 2013.

The package will be built by CU-Boulder's Laboratory for Atmospheric and Space Physics for the first flight of the National Polar Orbiting Operational Environmental Satellite System, or NPOESS. The instrument package had been canceled during the 2006 restructuring of the NPOESS program, a joint venture of the National Oceanic and Atmospheric Administration, NASA and the Air Force.

Known as the Total Solar Irradiance Sensor, or TSIS, the CU-Boulder package will fly on the first flight of NPOESS in 2013 and is anticipated to fly on two subsequent NPOESS missions slated for 2015 and 2020. The two latter NPOESS missions are expected to bring in an additional $30 million to CU-Boulder, said LASP Senior Researcher and TSIS Project Manager Tom Sparn.

TSIS consists of two instruments, including the Total Irradiance Monitor, or TIM, which measures the total light coming from the sun at all wavelengths, "a fundamental quantity for determining the energy balance of the planet," said TSIS principal investigator Peter Pilewskie of LASP......... Posted by: Sean      Read more         Source

May 7, 2008, 7:00 PM CT

New Type of Pulsating White Dwarf Star

University of Texas at Austin astronomers Michael H. Montgomery and Kurtis A. Williams, along with graduate student Steven DeGennaro, have predicted and confirmed the existence of a new type of variable star, with the help of the 2.1-meter Otto Struve Telescope at McDonald Observatory. The discovery is announced in today's issue of Astrophysical Journal Letters.

This research was funded by the National Science Foundation and the Delaware Asteroseismic Research Center.

Called a "pulsating carbon white dwarf," this is the first new class of variable white dwarf star discovered in more than 25 years. Because the overwhelming majority of stars in the universe--including the sun--will end their lives as white dwarfs, studying the pulsations (i.e., variations in light output) of these newly discovered examples gives astronomers a window on an important end point in the lives of most stars.

A white dwarf star is the leftover remnant of a sun-like star that has burned all of the nuclear fuel in its core. It is extremely dense, packing half to 1.5 times the sun's mass into a volume about the size of Earth. Until recently, there were believed to be two main types of white dwarfs: those with an outer layer of hydrogen (about 80 percent of white dwarfs), and those with an outer layer of helium, whose hydrogen shells have somehow been stripped away (the other 20 percent)......... Posted by: Sean      Read more         Source

May 5, 2008, 6:57 PM CT

65-million-year-old asteroid impact

The asteroid presumed to have wiped out the dinosaurs struck the Earth with such force that carbon deep in the Earth's crust liquefied, rocketed skyward, and formed tiny airborne beads that blanketed the planet, say researchers from the U.S., U.K., Italy, and New Zealand in this month's Geology.

The beads, known to geologists as carbon cenospheres, cannot be formed through the combustion of plant matter, contradicting a hypothesis that the cenospheres are the charred remains of an Earth on fire. If confirmed, the discovery suggests environmental circumstances accompanying the 65-million-year-old extinction event were slightly less dramatic than previously thought.

"Carbon embedded in the rocks was vaporized by the impact, eventually forming new carbon structures in the atmosphere," said Indiana University Bloomington geologist Simon Brassell, study coauthor and former adviser to the paper's lead author, Mark Harvey.

The carbon cenospheres were deposited 65 million years ago next to a thin layer of the element iridium -- an element more likely to be found in Solar System asteroids than in the Earth's crust. The iridium-laden dust is thought to bethe shattered remains of the 200-km-wide asteroid's impact. Like the iridium layer, the carbon cenospheres are apparently common. They've been found in Canada, Spain, Denmark and New Zealand......... Posted by: Sean      Read more         Source

April 30, 2008, 6:46 PM CT

Catching a Glimpse of a Black Hole's Fury

Using the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and a host of international telescope partners, a team of scientists has made the clearest observation yet of innermost region of a black hole.

From the observations, astronomers found good evidence that the enormous jets of particles emitted by supermassive black holes are corkscrewed in a way predicted by theory. The scientists believe the coiling is a result of twisted magnetic fields acting on the particle streams.

The scientists reported their findings in the April 24 issue of Nature

Led by Alan Marscher of Boston University, the international team of scientists studied the galaxy BL Lacertae located 950 million light years from Earth. By observing an outburst from the galaxy from late 2005 to 2006, the team observed bursts of photons oriented in a way predicted by theories about the twisted magnetic fields of black holes.

The VLBA is part of NSF's National Radio Astronomy Observatory (NRAO). A more detailed release--including graphics and a broadcast-quality animation--is available from NRAO at: http://www.nrao.edu/pr/2008/bllac.

Additional images, explanations, data sets and even a related song are available at a Web site posted by Marscher: http://www.bu.edu/blazars/BLLac.html........ Posted by: Sean      Read more         Source

April 30, 2008, 6:10 PM CT

Stellar Ticking Time Bomb Explodes on Cue

Using observations from NASA's Rossi X-ray Timing Explorer (RXTE), an international team of astronomers has discovered a timing mechanism that allows them to predict exactly when a superdense star will unleash incredibly powerful explosions.

"We found a clock that ticks slower and slower, and when it slows down too much, boom! The bomb explodes," says lead author Diego Altamirano of the University of Amsterdam in the Netherlands.

The bursts occur on a neutron star, which is the collapsed remnant of a massive star that exploded in a supernova. The neutron star belongs to a binary system that can be described as a ticking time bomb. Hydrogen and helium gas from a companion star spirals onto the neutron star, slowly accumulating on its surface until it heats up to a critical temperature. Suddenly, the hydrogen and helium begin to fuse uncontrollably into heavier elements, igniting a thermonuclear flame that quickly spreads around the entire star. The resulting explosion appears as a bright flash of X-rays.

These bursts, which can occur several times per day from the same neutron star, release more energy in just 10 to 100 seconds than our sun radiates in an entire week. Put another way, the energy is equivalent to 100 fifteen-megaton hydrogen bombs exploding simultaneously over each postage-stamp-size patch of the neutron star's surface......... Posted by: Sean      Read more         Source

April 24, 2008, 10:19 PM CT

Plethora Of Interacting Galaxies

Galaxy collisions produce a remarkable variety of intricate structures, as 59 new images from the NASA/ESA Hubble space telescope show.

Interacting galaxies are found throughout the Universe, sometimes dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that form new galaxies.

A series of 59 new images of colliding galaxies, the largest collection ever published simultaneously, has been released from archived raw Hubble images to mark the 18th anniversary of the telescope's launch.

Galaxy mergers, which were more common in the early Universe than they are today, are believed to be one of the main driving forces for cosmic evolution, turning on quasars, sparking frenetic star births and explosive stellar deaths.

Even apparently isolated galaxies will show signs in their internal structure that they have experienced one or more mergers in their past. Each of the various merging galaxies in this series of images is a snapshot of a different instant in the long interaction process.

For the entire collection of 59 images, please see this article on the European Hubble homepage......... Posted by: Sean      Read more         Source

April 13, 2008, 9:10 PM CT

Size and Frequency of Meteorite Impacts

Researchers have developed a new way of determining the size and frequency of meteorites that have collided with Earth.

Their work shows that the size of the meteorite that likely plummeted to Earth at the time of the Cretaceous-Tertiary (K-T) boundary 65 million years ago was four to six kilometers in diameter. The meteorite was the trigger, researchers believe, for the mass extinction of dinosaurs and other life forms.

François Paquay, a geologist at the University of Hawaii at Manoa (UHM), used variations (isotopes) of the rare element osmium in sediments at the ocean bottom to estimate the size of these meteorites. The results are published in this week's issue of the journal Science.

When meteorites collide with Earth, they carry a different osmium isotope ratio than the levels normally seen throughout the oceans.

"The vaporization of meteorites carries a pulse of this rare element into the area where they landed," says Rodey Batiza of the National Science Foundation (NSF)'s Division of Ocean Sciences, which funded the research along with NSF's Division of Earth Sciences. "The osmium mixes throughout the ocean quickly. Records of these impact-induced changes in ocean chemistry are then preserved in deep-sea sediments."

Paquay analyzed samples from two sites, Ocean Drilling Program (ODP) site 1219 (located in the Equatorial Pacific), and ODP site 1090 (located off of the tip of South Africa) and measured osmium isotope levels during the late Eocene period, a time during which large meteorite impacts are known to have occurred......... Posted by: Sean      Read more         Source

April 9, 2008, 10:02 PM CT

Rocket Mystery Explained With New Imaging Technique

There's a strange wave phenomenon that's plagued rocket researchers for years, a lurking threat with the power to destroy an engine at almost any time. For decades, researchers have had a limited understanding of how or why it happens because they could not replicate or investigate the problem under controlled laboratory conditions.

Researchers generally think that these powerful and unstable sound waves, created by energy supplied by the combustion process, were the cause of rocket failures in several U.S. and Russian rockets. Researchers have also observed these mysterious oscillations in other propulsion and power-generating systems such as missiles and gas turbines.

Now, scientists at the Georgia Institute of Technology have developed a liquid rocket engine simulator and imaging techniques that can help demystify the cause of these explosive sound waves and bring researchers a little closer to being able to understand and prevent them. The Georgia Tech research team was able to clearly demonstrate that the phenomenon manifests itself in the form of spinning acoustic waves that gain destructive power as they rotate around the rocket's combustion chamber.

"This is a very troublesome phenomenon in rockets," said Ben Zinn, the David S. Lewis Jr. Chair and Regents' Professor in the Guggenheim School of Aerospace Engineering at Georgia Tech. "These spinning acoustic oscillations destroy engines without anyone fully understanding how these waves are formed. Visualizing this phenomenon brings us a step closer to understanding it."........ Posted by: Sean      Read more         Source