Water Ice Discovered On Asteroid

Water ice has been found on the surface of a nearby asteroid for the first time – a discovery that could help explain how Earth got its oceans, scientists announced.

Two teams of researchers independently verified that the asteroid 24 Themis – a large rock hurtling through space in the asteroid belt between Mars and Jupiter – is coated in a layer of frost.

They also found that the asteroid contains organic material, including some molecules that might be ingredients for life. But scientists have not found any evidence for life itself on this asteroid, or anywhere else in the universe beyond Earth.

“This is the first time we’ve actually seen ice – literally H20 – on an asteroid,” said one of the study leaders, Andrew Rivkin of Johns Hopkins University.

Previously, hints that water might be present on 24 Themis were found in the form of hydrated minerals, which were thought to have formed from the reaction of water with rock. But this time the researchers saw the direct signature of water itself, he explained.

Another science team, led by Humberto Campins of University of Central Florida, found the same thing. Both teams used the NASA Infrared Telescope Facility atop on Mauna Kea in Hawaii to make their observations, but conducted them on different nights.

“Our work and their work are very nicely confirming and complementary,” Campins said.

“To our surprise there was water ice, there were organic molecules, and they were more or less evenly distributed throughout the surface,” Campins told, “We thought that was fascinating.”

Both teams reported their findings in the 19 April 2010 issue of the journal Nature.

Archaeopteryx fossil seen in new light

The feathers preserved in a 150-million-year-old fossil of Archaeopteryx aren’t just casts of the primitive bird’s plumage, as paleontologists have long presumed: Amazingly, the structures retain chemical elements from the original feathers, a a new X-ray imaging technique reveals.

“People have been looking at these [feathers] a long time and thought they were just impressions, but there’s actually remains of soft tissue there,” says Roy Wogelius, a geochemist at the University of Manchester in England.

He and his colleagues report their find online during the week of May 10 and in an upcoming Proceedings of the National Academy of Sciences.

The new technique is “opening up a new window into the chemistry of fossils,” says Derek Briggs, a paleontologist at Yale University.

In particular, the new images show high concentrations of phosphorus — an element found in abundance in the feathers of modern birds but not in the rocks surrounding the Archaeopteryx fossil — in the shafts and vanes of the fossil’s feathers. The key to the new finding is a recently developed imaging technique that illuminates the fossil with intense X-rays and causes trace elements in the fossil to fluoresce. Previously, similar techniques that lit a surface with low-intensity X-rays required 24 hours to image each square centimeter of a surface. The new scheme, which uses high-intensity X-rays produced by a synchrotron to repeatedly scan an object, takes just 30 seconds to image the same area — a time savings that allows researchers to scan large objects in a short amount of time.

“It’s like using a spotlight versus a key-chain torchlight to illuminate a picture,” Wogelius explains. The technique can detect certain chemical elements at concentrations of just a few parts per million.

Besides the startling finding of phosphorus in the ancient fossil’s feathers, the team’s new analyses suggest that the fossil’s bones retain traces of their original zinc. Comparisons with the chemical composition of modern bird bones suggest that about half of the bones’ original zinc remains.

The chemical elements remained largely unaltered because both the Archaeopteryx bones and the sediments encasing them are rich in calcium.

“These are very exciting results”

“What this team has found simply wasn’t available by any other method”

Not only that,

The new X-ray imaging technique is great because it’s nondestructive ─ which is particularly useful for exceptionally rare fossils such as Archaeopteryx, of which only 10 specimens have been found in the past century and a half.

“You can get all this spectral information without ever touching the fossil”

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