Could Life on Earth Have Come From Space?

People who search for aliens on Earth are likely thinking of little green men and flying saucers in the sky, but what if they should be looking at tentacles in the sea? A recent paper claims that octopuses and other cephalopods have their origins on a different planet, brought here as eggs on some asteroid in our planet’s distant past.
It’s a pretty far-fetched idea, and almost certainly not true, but the idea of life on Earth originating from somewhere else is not as completely ridiculous as it might seem. The idea is called ‘panspermia,’ and while there’s not a whole lot of evidence supporting it, it’s also not impossible.
Panspermia, broadly defined, is the idea that living organisms or genetic material can travel between planets in our solar system, and even between our solar system and nearby stars.
Some life forms—like tardigrades and certain species of bacteria and fungus—can survive for extended periods in the vacuum of space. An experiment on the ISS found that a number of microbes survived just fine in space for nearly two years, and it’s almost guaranteed that some species can survive for longer. In fact, microorganisms surviving in space is such a problem for NASA that the agency has a ‘Planetary Protection Officer’ devoted to making sure it doesn’t happen by accident.
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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