Is Space Dust Spreading Life on Earth to Other Planets?

Monday, 20 November 2017 - 1:27PM
Earth
Monday, 20 November 2017 - 1:27PM
Is Space Dust Spreading Life on Earth to Other Planets?
Image credit: NASA
The building blocks of life on Earth may be launching into space, perhaps seeding other worlds, according to a recent study.

"Hypervelocity space dust" is constantly blowing into the Earth's atmosphere, Arjun Berera, a professor of the School of Physics and Astronomy at the University of Edinburgh, announced in a recent paper. 

Such an endless stream creates action with those particles colliding with the atoms, molecules and other particles that form Earth's atmosphere, which can include microbial life and life-essential fragments—Dr. Berera describes these as "telltale signs of Earth's organic story."

Such turbulence in our atmosphere, ever being stirred by the ceaseless entrance of space dust may mean some Earth-native molecules are heading out into space, is possibly seeding other planets. 
 
"[There's a] possibility that such collisions can give particles in the atmosphere the necessary escape velocity and upward trajectory to escape Earth's gravity," writes Dr. Berera.
 
Gravity doesn't help. Escaping the pull of Earth requires forces that can get the particles to the necessary escape velocity—and that isn't always enough. As if such a speed-up takes place too low in the air, atmospheric density will create drag that can slow their movement. This action can also create such intense heat that the bits evaporate. However, particles high in the mesosphere and thermosphere would be less affected—and Dr. Berera believes that space dust smashing our way could send earthborn molecules up and out into space. 
 
However, space dust seeding the universe with life from Earth isn't quite that simple. "As for larger particles capable of harboring biological constituents, the most likely scenario for thrusting them into space would require a double-stage approach, whereby they are first hurled into the lower thermosphere region or higher by some mechanism and then given an even stronger kick by fast space dust collision, which eventually leads to escape velocity and an exit from the Earth's gravity," Dr. Berera adds. 
 


Earthly organic material wouldn't have it easy once away from the atmosphere, considering the lethal environment of space, but Dr. Berera reminds that "bacterial spores have been left on the exterior of the International Space Station…in a near vacuum environment of space, where there is nearly no water, considerable radiation, and with temperatures ranging from 332K (about 138-degrees Fahrenheit) on the sun side to 252K (approximately -6-degrees F) on the shadow side, and have survived 1.5 years."

Add in the success that tiny tardigrades have shown against extreme pressure and temperatures, and the way extremophiles prosper on Earth, and the professor finds that native elements of life freed from Earth's atmosphere may have blown around the solar system, "possibly eventually landing on another planet" and that the colliding of space dust with our world might "provide a universal mechanism both for the exchange of the atomic and molecular constituents between distant planetary atmospheres and for initiating the first step of the panspermia process."

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Is Space Dust Spreading Life on Earth to Other Planets?
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