Archive for ‘Astrobiology’

November 4, 2011

Life on Mars Driven Underground?

According to Andrew Marvell, “The grave’s a fine and private place, But none I think do there embrace.”

It’s also a lonely place – and so, as far as we can now tell, the grave and the universe have a lot in common. This is probably why humans have such a desperate need to imagine life existing elsewhere in the universe.

Well, planetary scientists are on the same page, and they keep coming up with evidence that life might, just possibly, have existed on Mars at some time, probably in the distant past. Even if it’s only bacteria. Hey, that may be better than nothing, though bacteria aren’t normally considered especially huggable.

Not too long ago, it came out that at one time – oh, about 4 billion years ago – there may have been somewhere on Mars that was almost Earthlike balmy, and wet as well.

But the very latest research suggests that somewhere was subterranean. (Yes, it’s not quite the applicable term on Mars.)

Life on Mars Driven Underground?

Today’s cold, dry, and likely lifeless martian surface extends back in martian history past the time when life was taking hold on Earth, according to a new study. But researchers have also found that liquid and likely warm water persisted kilometers below the surface at the same critical time for life. Not exactly Darwin’s “warm little pond” for the beginnings of biology, but it might well have served.

It might have served, if the life there didn’t tend to be claustrophobic.

NASA Study: On Mars, Water Went Underground

Discovery of clay minerals on Mars in 2005 indicated the planet once hosted warm, wet conditions. If those conditions existed on the surface for a long era, the planet would have needed a much thicker atmosphere than it has now, to keep the water from evaporating or freezing. Researchers have sought evidence of processes by which such a thick atmosphere may have been lost over time.

This new study supports an alternative hypothesis, that persistent warm water was confined to the subsurface and that many erosional features were carved during brief periods when liquid water was stable at the surface.

That’s not a deal-breaker for the existence of (bacterial) life, since there’s substantial evidence that Earth has a thriving biosphere deep beneath the surface. But still, that seems a lot more like a crypt than a Cozumel.

Further reading:

NASA Study of Clays Suggests Watery Mars Underground

Mars’ history is a fluid situation

Subsurface water and clay mineral formation during the early history of Mars

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September 5, 2011

Alien Life More Likely on ‘Dune’ Planets

Alien Life More Likely on ‘Dune’ Planets – Astrobiology Magazine

Desert planets strikingly like the world depicted in the science fiction classic “Dune” might be the more common type of habitable planet in the galaxy, rather than watery planets such as Earth, researchers suggest.

Their findings also hint that Venus might have been a habitable desert world as recently as 1 billion years ago.

Nearly everywhere there is water on Earth, there is life. As such, the search for life elsewhere in the universe has largely focused on “aqua planets” with a lot of liquid water on their surfaces — either terrestrial planets largely covered with oceans, such as Earth, or theoretical “ocean planets” completely covered by a layer of water hundreds of miles deep, somewhat like thawed versions of Jupiter’s moon Ganymede.

August 19, 2011

The amino acid alphabet

Amino acid alphabet soup

Via Physorg.com, 8/19/11

All living creatures on this planet use the same 20 amino acids, even though there are hundreds available in nature. Scientists therefore have wondered if life could have arisen based on a different set of amino acids. And what’s more, could life exist elsewhere that utilizes an alternate collection of building blocks?

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