Archive

Archive for January 25, 2012

Vesta Likely Cold and Dark Enough for Ice

January 25, 2012 Leave a comment

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Though generally thought to be quite dry, roughly half of the giant asteroid Vesta is expected to be so cold and to receive so little sunlight that water ice could have survived there for billions of years, according to the first published models of Vesta’s average global temperatures and illumination by the sun.

“Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface,” says Timothy Stubbs of NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County. Stubbs and Yongli Wang of the Goddard Planetary Heliophysics Institute at the University of Maryland published the models in the January 2012 issue of the journal Icarus. The models are based on information from telescopes including NASA’s Hubble Space Telescope.

Vesta, the second-most massive object in the asteroid belt between Mars and Jupiter, probably does not have any significant permanently shadowed craters where water ice could stay frozen on the surface all the time, not even in the roughly 300-mile-diameter (480-kilometer-diameter) crater near the south pole, the authors note. The asteroid isn’t a good candidate for permanent shadowing because it is tilted on its axis at about 27 degrees, which is even greater than Earth’s tilt of roughly 23 degrees. In contrast, the moon, which does have permanently shadowed craters, is tilted at only about 1.5 degrees. As a result of its large tilt, Vesta has seasons, and every part of the surface is expected to see the sun at some point during Vesta’s year.

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2012-024

Durable NASA Rover Beginning Ninth Year of Mars Work

January 25, 2012 2 comments

Image credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.

Image credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.

Eight years after landing on Mars for what was planned as a three-month mission, NASA’s enduring Mars Exploration Rover Opportunity is working on what essentially became a new mission five months ago.

Opportunity reached a multi-year driving destination, Endeavour Crater, in August 2011. At Endeavour’s rim, it has gained access to geological deposits from an earlier period of Martian history than anything it examined during its first seven years. It also has begun an investigation of the planet’s deep interior that takes advantage of staying in one place for the Martian winter.

Opportunity landed in Eagle Crater on Mars on Jan. 25, 2004, Universal Time and EST (Jan. 24, PST), three weeks after its rover twin, Spirit, landed halfway around the planet. In backyard-size Eagle Crater, Opportunity found evidence of an ancient wet environment. The mission met all its goals within the originally planned span of three months. During most of the next four years, it explored successively larger and deeper craters, adding evidence about wet and dry periods from the same era as the Eagle Crater deposits.

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2012-022

Wild Early Lives of Today’s Most Massive Galaxies

January 25, 2012 Leave a comment

Credit: ESO, APEX (MPIfR/ESO/OSO), A. Weiss et al., NASA Spitzer Science Center

Credit: ESO, APEX (MPIfR/ESO/OSO), A. Weiss et al., NASA Spitzer Science Center

Using the APEX telescope, a team of astronomers has found the strongest link so far between the most powerful bursts of star formation in the early Universe, and the most massive galaxies found today. The galaxies, flowering with dramatic starbursts in the early Universe, saw the birth of new stars abruptly cut short, leaving them as massive — but passive — galaxies of aging stars in the present day. The astronomers also have a likely culprit for the sudden end to the starbursts: the emergence of supermassive black holes.

Astronomers have combined observations from the LABOCA camera on the ESO-operated 12-metre Atacama Pathfinder Experiment (APEX) telescope with measurements made with ESO’s Very Large Telescope, NASA’s Spitzer Space Telescope, and others, to look at the way that bright, distant galaxies are gathered together in groups or clusters.

The more closely the galaxies are clustered, the more massive are their halos of dark matter — the invisible material that makes up the vast majority of a galaxy’s mass. The new results are the most accurate clustering measurements ever made for this type of galaxy.

Full Story: http://www.eso.org/public/news/eso1206/

Elusive Matter Found To Be Abundant Far Above Earth

January 25, 2012 Leave a comment

Cold plasma has been well-hidden. Space physicists have long lacked clues to how much of this electrically charged gas exists tens of thousands of miles above Earth and how the stuff may impact our planet’s interaction with the sun. Now, a new method developed by Swedish researchers makes cold plasma measurable and reveals significantly more cold, charged ions in Earth’s upper altitudes than previously imagined.

At these lofty elevations, storms of high-energy charged particles — space weather — roil the atmosphere, creating auroras, buffeting satellites, and sometimes wreaking havoc with electronic devices and electric grids on Earth. The new evidence of abundant cold (i.e. low-energy) ions may change our understanding of this tumultuous space weather and lead to more accurate forecasting of it, scientists say. The finding might also shed light on what’s happening around other planets and moons — for instance, helping explain why the once robust atmosphere of Mars is so wispy today.

“The more you look for low-energy ions, the more you find,” said Mats André, a professor of space physics at the Swedish Institute of Space Physics in Uppsala, Sweden, and leader of the research team. “We didn’t know how much was out there. It’s more than even I thought.”

Full Story: http://www.agu.org/news/press/pr_archives/2012/2012-02.shtml

Follow

Get every new post delivered to your Inbox.

Join 373 other followers