Dust from the great beyond

Interstellar grains seen by the Cassini spacecraft lend support to the old panspermia hypothesis.
By Dirk Schulze-Makuch
airspacemag.com
April 21, 2016

After analyzing ten years of data from the Cassini spacecraft that’s been orbiting Saturn since 2004, a team of scientists led by Nicolas Altobelli of the European Space Agency in Madrid, Spain, reports finding dust that came from outside our solar system. Along with millions of ice-rich dust particles shed by Saturn’s moons, Cassini’s Cosmic Dust Analyzer detected a grand total of 36 grains that the scientists could trace back to the local interstellar cloud. That cloud is an almost empty bubble of gas through which our solar system is currently moving.
The small interstellar dust grains were zipping past Saturn at speeds of over 72,000 kilometers per hour (44,000 mph), which explains how they avoided becoming gravitationally trapped by the sun. This marks the first time scientists have been able to analyze material from outside our solar system. Intriguingly, the Cassini Cosmic Dust Analyzer saw the same kind of chemical and mineralogical make-up in the interstellar grains as it did in the local dust.
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Rosetta probe Philae discovers organic molecules on comet

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Wall Street Journal
By Gautam Naik

The probe that landed on the surface of a comet has discovered organic molecules, the most rudimentary building blocks of life, according to the German agency involved in the mission.

Philae-landerAn instrument aboard the Philae lander detected the molecules after “sniffing” the comet’s atmosphere. An organic compound is one whose molecules contain the carbon atom, the basis of life on earth.

Scientists are analyzing the data to see whether the organic compounds detected by Philae are simple ones—such as methane and methanol—or a more complex species such as amino acids, the building blocks for proteins. A drill on Philae also obtained some material from the comet’s hard surface, but data about organic molecules from that experiment have yet to be fully analyzed.

Comets contain some of the most pristine materials in the solar system, dating to about 4.5 billion years ago. Previous studies have suggested that comets forge organic material in their dusty atmospheres.

Read more: http://online.wsj.com/articles/rosetta-probe-directly-discovers-organic-molecules-on-comet-1416256078

Space station experiment identifies microbes that can survive unprotected in space

by Will Parker
Scientists conducting a series of experiments on the International Space Station say that some micro-organisms can survive for long periods exposed to the hostile environment of outer space. The findings, published in the Astrobiology Journal, lend weight to the concept of panspermia, where life on Earth emerged from bacterial colonies transported on comets and asteroids.
The experiments were designed to see whether bacterial hitchhikers on spacecraft were hardy enough to survive in space and contaminate other planets. Currently, spacecraft landing on Mars or other planets where life might exist must meet requirements for a maximum allowable level of microbial life (known as bioburden). These acceptable levels were based on studies of how various life forms survive exposure to the rigors associated with space travel.
“If you are able to reduce the numbers to acceptable levels, a proxy for cleanliness, the assumption is that the life forms will not survive under harsh space conditions,” explains NASA’s Kasthuri J. Venkateswaran. But that assumption may not hold up, as it seems some microbes are hardier than expected.

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