July 8, 2010, 7:02 AM CT

Newborn Stars Discovered

A wave of massive star formation appears poised to begin within a mysterious, dark cloud in the Milky Way. NASA's Spitzer Space Telescope has revealed a secluded birthplace for stars within a wispy, dark cloud named named M17 SWex. The dark cloud is part of the larger, parent nebula known as M17, a vast region of our galaxy with a bright, central star cluster. "We believe we've managed to observe this dark cloud in a very early phase of star formation before its most massive stars have ignited," said Penn State astronomer Matthew Povich, a postdoctoral fellow and the main author of a study published recently in The Astrophysical Journal Letters. The new research could shed light on the question of how and when massive stars form.

Though astronomers first discovered the dark cloud in the Sagittarius constellation more than 30 years ago, it took the keenness of the Spitzer telescope's instruments to spot the hidden stellar nursery within. Spitzer's infrared vision has shown that M17 SWex is among the closest to Earth and also among the Milky Way's busiest star-making factories, with 488 newly forming stars. More than 200 will become blue-white class B stars, larger and hotter than our Sun. "Most of the stars we've detected are relatively bright," said Povich. "So we predict the actual number of stars forming in M17 SWex is over 10,000, since the fainter stars cannot be detected with the current observations"......... Posted by: Sean      Read more         Source

June 30, 2010, 6:42 AM CT

Zapping Titan-like atmosphere with UV rays

The first experimental evidence showing how atmospheric nitrogen can be incorporated into organic macromolecules is being reported by a University of Arizona team.

The finding indicates what organic molecules might be found on Titan, the moon of Saturn that researchers think is a model for the chemistry of pre-life Earth.

Earth and Titan are the only known planetary-sized bodies that have thick, predominantly nitrogen atmospheres, said Hiroshi Imanaka, who conducted the research while a member of UA's chemistry and biochemistry department.

How complex organic molecules become nitrogenated in settings like early Earth or Titan's atmosphere is a big mystery, Imanaka said.

"Titan is so interesting because its nitrogen-dominated atmosphere and organic chemistry might give us a clue to the origin of life on our Earth," said Imanaka, now an assistant research scientist in the UA's Lunar and Planetary Laboratory. "Nitrogen is an essential element of life".

However, not just any nitrogen will do. Nitrogen gas must be converted to a more chemically active form of nitrogen that can drive the reactions that form the basis of biological systems.

Imanaka and Mark Smith converted a nitrogen-methane gas mixture similar to Titan's atmosphere into a collection of nitrogen-containing organic molecules by irradiating the gas with high-energy UV rays. The laboratory set-up was designed to mimic how solar radiation affects Titan's atmosphere......... Posted by: Sean      Read more         Source

June 24, 2010, 11:06 PM CT

Widespread Glacial Meltwater Valleys on Mars

Planetary researchers have uncovered telltale signs of water on Mars - frozen and liquid - in the earliest period of the Red Planet's history. A new claim, made public this month, is that a deep ocean covered some of the northern latitudes.

But the evidence for water grows much more scant after the Noachian era, which ended 3.5 billion years ago. Now Brown University planetary geologists have documented running water that sprang from glaciers throughout the Martian middle latitudes as recently as the Amazonian epoch, several hundred million years ago. These glaciofluvial valleys were, in essence, tributaries of water created when enough sunlight reached the glaciers to melt a thin layer on the surface. This, the Brown scientists write, led to "limited surface melting" that formed channels that ran for several kilometers and could be more than 150 feet wide.

The finding is "more than 'Yes, we found water,'" said Caleb Fassett, postdoctoral research associate in geological sciences and main author of the paper published in Icarus. "What we see now is there's this complex history of different environments where water is being formed".

Caleb Fassett Fassett, with Brown research analyst James Dickson, professor James Head III, and geologists from Boston University and Portland State University, analyzed 15,000 images snapped by the Context Camera (CTX) aboard the Mars Reconnaissance Orbiter to compile the first survey of glaciofluvial valleys on Mars. The survey was sparked by a glaciofluvial valley that Dickson, Fassett, and Head spotted within the Lyot crater, located in the planet's middle latitudes. The team, in a paper last year in Geophysical Research Letters, dated that meltwater-inspired feature to the Amazonian......... Posted by: Sean      Read more         Source

June 24, 2010, 10:58 PM CT

Was Venus once a habitable planet?

ESA's Venus Express is helping planetary researchers investigate whether Venus once had oceans. If it did, it may even have begun its existence as a habitable planet similar to Earth.

These days, Earth and Venus seem completely different. Earth is a lush, clement world teeming with life, whilst Venus is hellish, its surface roasting at temperatures higher than those of a kitchen oven.

But underneath it all the two planets share many striking similarities. They are nearly identical in size and now, thanks to ESA's Venus Express orbiter, planetary researchers are seeing other similarities too.

"The basic composition of Venus and Earth is very similar," says Håkan Svedhem, ESA Venus Express Project Scientist. Just how similar planetary researchers from around the world will be discussing in Aussois, France, where they are gathering this week for a conference.

One difference stands out: Venus has very little water. Were the contents of Earth's oceans to be spread evenly across the world, they would create a layer 3 km deep. If you were to condense the amount of water vapour in Venus' atmosphere onto its surface, it would create a global puddle just 3 cm deep.

Yet there is another similarity here. Billions of years ago, Venus probably had much more water. Venus Express has certainly confirmed that the planet has lost a large quantity of water into space......... Posted by: Sean      Read more         Source

June 13, 2010, 10:37 PM CT

Ancient ocean may have covered one-third of Mars

A vast ocean likely covered one-third of the surface of Mars some 3.5 billion years ago, as per a newly released study conducted by University of Colorado at Boulder scientists.

The CU-Boulder study is the first to combine the analysis of water-related features including scores of delta deposits and thousands of river valleys to test for the occurrence of an ocean sustained by a global hydrosphere on early Mars. While the notion of a large, ancient ocean on Mars has been repeatedly proposed and challenged over the past two decades, the newly released study provides further support for the idea of a sustained sea on the Red Planet during the Noachian era more than 3 billion years ago, said CU-Boulder researcher Gaetano Di Achille, main author on the study.

A paper on the subject authored by Di Achille and CU-Boulder Assistant Professor Brian Hynek of the geological sciences department appears in the June 13 issue of Nature Geoscience Both Di Achille and Hynek are affiliated with CU-Boulder's Laboratory for Atmospheric and Space Physics.

More than half of the 52 river delta deposits identified by the CU scientists in the newly released study -- each of which was fed by numerous river valleys -- likely marked the boundaries of the proposed ocean, since all were at about the same elevation. Twenty-nine of the 52 deltas were connected either to the ancient Mars ocean or to the groundwater table of the ocean and to several large, adjacent lakes, Di Achille said......... Posted by: Sean      Read more         Source

May 21, 2010, 7:12 AM CT

Brightest galaxies tend to cluster in busiest parts of universe

For more than a decade, astronomers have been puzzled by bright galaxies in the distant universe that appear to be forming stars at phenomenal rates. What prompted the prolific star creation, they wondered. And what kind of spatial environment did these galaxies inhabit?

Now, using a super-sensitive camera/spectrometer on the Herschel Space Observatory, astronomers - including a UC Irvine team led by Asantha Cooray - have mapped the skies as they appeared 10 billion years ago.

The UCI researchers discovered that these glistening galaxies preferentially occupy regions of the universe containing more dark matter and that collisions probably caused the abundant star production.

"Thanks to the superb resolution and sensitivity of the SPIRE [Spectral & Photometric Imaging Receiver] instrument on Herschel, we managed to map in detail the spatial distribution of massively star-forming galaxies in the early universe," said Cooray, associate professor and Chancellor's Fellow in physics & astronomy. "All indications are that these galaxies are. crashing, merging and possibly settling down at centers of large dark-matter halos".

This information will enable researchers to adapt conventional theories of galaxy formation to accommodate the strange, star-filled versions......... Posted by: Sean      Read more         Source

April 2, 2010, 7:00 AM CT

Active galaxy's 'smokestack plumes'

If our eyes could see radio waves, the nearby galaxy Centaurus A (Cen A) would be one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon. What we can't see when looking at the galaxy in visible light is that it lies nestled between a pair of giant radio-emitting gas plumes ejected by its supersized black hole. Each plume is nearly a million light-years long.

NASA's Fermi Gamma-Ray Space Telescope maps gamma rays, radiation that typically packs 100 billion times the energy of radio waves. Nevertheless, and to the surprise of a number of astrophysicists, Cen A's plumes show up clearly in the satellite's first 10 months of data. The study appears in Thursday's edition of Science Express.

"This is something we've never seen before in gamma rays," said Teddy Cheung, a Fermi team member at the Naval Research Laboratory in Washington. "Not only do we see the extended radio lobes, but their gamma-ray output is more than ten times greater than their radio output." If gamma-ray telescopes had matured before their radio counterparts, astronomers would have instead classified Cen A as a "gamma-ray galaxy".

Also known as NGC 5128, Cen A is located about 12 million light-years away in the constellation Centaurus and is one of the first celestial radio sources identified with a galaxy. "A hallmark of radio galaxies is the presence of huge, double-lobed radio-emitting structures around otherwise normal-looking elliptical galaxies," said Jrgen Kndlseder, a Fermi collaborator at the Center for the Study of Space Radiation in Toulouse, France. "Cen A is a textbook example"......... Posted by: Sean      Read more         Source

March 25, 2010, 7:59 PM CT

Hubble confirms cosmic acceleration

A group of astronomers [1], led by Tim Schrabback of the Leiden Observatory, conducted an intensive study of over 446 000 galaxies within the COSMOS field, the result of the largest survey ever conducted with Hubble. In making the COSMOS survey, Hubble photographed 575 slightly overlapping views of the same part of the Universe using the Advanced Camera for Surveys (ACS) onboard Hubble. It took nearly 1000 hours of observations.

In addition to the Hubble data, scientists used redshift [2] data from ground-based telescopes to assign distances to 194 000 of the galaxies surveyed (out to a redshift of 5). "The sheer number of galaxies included in this type of analysis is unprecedented, but more important is the wealth of information we could obtain about the invisible structures in the Universe from this exceptional dataset," says co-author Patrick Simon from Edinburgh University.

In particular, the astronomers could "weigh" the large-scale matter distribution in space over large distances. To do this, they made use of the fact that this information is encoded in the distorted shapes of distant galaxies, a phenomenon referred to as weak gravitational lensing [3]. Using complex algorithms, the team led by Schrabback has improved the standard method and obtained galaxy shape measurements to an unprecedented precision. The results of the study will be published in an upcoming issue of Astronomy and Astrophysics........ Posted by: Sean      Read more         Source

March 22, 2010, 7:49 PM CT

Sharpest view ever of star factories

Astronomers have combined a natural gravitational lens and a sophisticated telescope array to get the sharpest view ever of "star factories" in a galaxy over 10 billion light-years from Earth. They observed that the distant galaxy, known as SMM J2135-0102, is making new stars 250 times faster than our Galaxy, the Milky Way.

They also pinpointed four discrete star-forming regions within the galaxy, each over 100 times brighter than locations (like the Orion Nebula) where stars form in our Galaxy. This is the first time that astronomers have been able to study properties of individual star-forming regions within a galaxy so far from Earth.

"To a layperson, our images appear fuzzy, but to us, they show the exquisite detail of a Faberge egg," said Steven Longmore of the Harvard-Smithsonian Center for Astrophysics (CfA). Longmore is an author of the paper describing these findings, which was reported in the March 21st Nature online.

Due to the time it takes light to travel to us, we see the galaxy as it existed just 3 billion years after the Big Bang. It was Milky Way-sized at the time. If we could see it today, 10 billion years later, it would have grown into a giant elliptical galaxy much more massive than our own.

"This galaxy is like a teenager going through a growth spurt," said Mark Swinbank of Durham University, main author on the paper. "If you could see it today as an 'adult,' you'd find the galactic equivalent of Yao Ming the basketball player"......... Posted by: Sean      Read more         Source

March 22, 2010, 7:43 PM CT

Early galaxy went through teenage growth spurt

Researchers have found a massive galaxy in the early Universe creating stars like our sun up to 100 times faster than the modern-day Milky Way.

The team of international researchers, led by Durham University, described the finding as like seeing "a teenager going through a growth spurt".

Due to the amount of time it takes light to reach Earth the researchers observed the galaxy as it would have appeared 10 billion years ago just three billion years after the Big Bang.

They found four discrete star-forming regions within the galaxy known as SMM J2135-0102. Each region was more than 100 times brighter than star-forming regions in the Milky Way, such as the Orion Nebula.

They say their results, published online today (Sunday, March 21), in the prestigious scientific journal Nature, suggest that star formation was more rapid and vigorous in the early Universe as galaxies went through periods of huge growth.

The findings, funded by the Royal Astronomical Society and the Science and Technology Facilities Council, provide a unique insight into how stars formed in the early Universe, the researchers added.

Main author Dr Mark Swinbank, in the Institute for Computational Cosmology, at Durham University, said: "This galaxy is like a teenager going through a growth spurt. If you could see it today as an adult you'd find the galactic equivalent of the football player Peter Crouch......... Posted by: Sean      Read more         Source