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The Limits of Organic Life in Planetary Systems.


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Comet Linear VZ13.
comet Linear VZ13. Image: Galactic2000.

Today's astrophoto comes from Galactic2000, and it's of comet Comet Linear C/2006 VZ13
Unpacking woes continue... but here's some astrosphere for you.

First up, Pamela Gay reports on the chances we'll hear alien radio transmissions.

Then Centauri Dreams discusses red dwarfs and planetary anomalies.

Astroblog shows you how to make a stereo anaglyph of the Sun.

It turns out, the Hitchhiker's Guide to the Galaxy was right. 42 is the secret to life, the universe and everything.

How Different Could Life Be?

Hazy titan. Image credit: NASA/JPL/SSI.
July 10th, 2007: Hazy titan. Image credit: NASA/JPL/SSI.

Over the last few years, biologists have been continuously surprised at life's ability to survive in extreme environments: in freezing and boiling temperatures, deep underground, and at the bottom of the ocean around geothermal vents. The common ingredients are liquid water, carbon, and an energy source. But in a new research report developed by the National Research Council, entitled The Limits of Organic Life in Planetary Systems, a multidisciplinary team of scientists investigated alternative ways that life could exist and even thrive.

Life that would be completely alien to the processes we have here on Earth.

The assumption about the search for life in the solar system is that it would share certain traits in common with life "as we know it". That means liquid water as a solvent, so that organic molecules can interact in solution. Animal metabolism would require carbon to provide energy storage, chemical reactions and the creation of structures.

But according to this paper, water isn't the only biosolvent that life could use. In fact, it's not even the best one. For example, on Saturn's frigid Moon Titan, liquid ammonia could act as a solvent. Non-carbon-based molecules could serve the functions of storage, structure and chemical reactions.

This paper suggests that researchers should expand their understanding of what forms life could take here on Earth, as well as the environments that it could exist in. It also encourages space mission designers to make their experiments more flexible, able to detect unusual life processes, instead of the plain old water/carbon life we've got here on Earth.

You can read the http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11919 press release here, or download http://books.nap.edu/catalog.php?record_id=11919 the entire report as a PDF file or read it online. Don't worry, it's really well written and very accessible to most readers, just scan past the pages of organic molecules and enjoy the writing.

Killer Electrons From Space!

Earth's magnetosphere. Image credit: NASA.
July 10th, 2007: Earth's magnetosphere. Image credit: NASA.

Space travel is dangerous, make no mistake. So many ways to die. But now scientists think they've got a handle on how one of the threats operates: killer electrons from space.

Using data from a fleet of spacecraft, scientists at the Los Alamos National Laboratory have puzzled out how electromagnetic waves accelerate normal electrons in the Earth's radiation belts to killer velocities. These electrons are then hazardous to satellites, spacecraft, and especially astronauts.

Their research, entitled The Energization of Relativistic electrons in the Outer Van Allen Radiation Belt was published in the July issue of Nature Physics.

They measured the fluxes of electrons striking a satellite-mounted detector, and the converted the measurements to magnetic coordinates. This showed them that the local peaks in electrons could have only been caused by the acceleration of electrons by electromagnetic waves. They still don't understand the exact mechanism that's causing the acceleration, though.

Two new NASA spacecraft are due to be launched in 2012 - the Radiation Belt Storm probes - these will help scientists understand the mechanism more deeply.




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