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Presence of Life may be Required to Maintain Habitability of a Planet over Billions of Years



Researchers from the Australian National University Planetary Science Institute have discovered that rocky, Earth-like planets are probably more abundant than stars. The institute is a joint venture of the Research School of Astronomy and Astrophysics and the Research School of Earth Sciences.

“Determining whether these planets are habitable has become the new holy grail of astronomy,” said planetary scientist Dr Charley Lineweaver, lead author of the study at the The Australian National University.

“The new-found abundance of planets, combined with the much larger range of inhabited terrestrial environments suggests that habitable planets are common. This increases the probability of finding some kind of extraterrestrial life,” he said.

“By comparing the inhabited and uninhabited regions of Earth, we can identify the most important factors that determine habitability. For terrestrial life, those factors are liquid water, a narrow range of temperature, and an energy source,” said Aditya Chopra also at the Australian National University.

“Habitability is not just a question of abiotic environmental conditions – the presence of life may be required to maintain the habitability of a planet over billions of years," added Lineweaver. “Planetary habitability is a complex and confusing concept that we are only beginning to get our heads around, but as a species that wants to survive, it is in our interest to get our heads around it soon.”

The research has been published in the paper, "The Habitability of Our Earth and Other Earths: Astrophysical, Geochemical, Geophysical, and Biological Limits on Planet Habitability", online in the Annual Reviews of Earth and Planetary Sciences.




The Daily Galaxy via Australian National University.

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Maybe it's just me, but I thought that this conclusion (the one in the headline, that the presence of life is needed to maintain long-term habitability) was an obvious and already-established one. Was there a question about it?

Regarding the video (which, by the way, is a good inclusion), Dr. Lineweaver pretty much lays out my biggest reason for doubting the presence of intelligent life elsewhere in the Milky Way.

@Bob Greenwade:

Well... I hate to admit it, but I always thought that human-like intelligence is an obvious, inevitable, and universal outcome of evolution.

I've been reading science magazines (and later science websites) since childhood, and still I fell victim to that fallacy.

So I'm guessing that theory may not be obvious to many other people (including fellow science-geeks) as well...

It's actually a bit discouraging to think that human-like intelligence, or hyper-intelligence is not an inevitable outcome in evolution...


As you pointed it in your comment above, that may indeed explain why we seem to be alone.

But perhaps it is for the best... If humans are any indication of what a hyper intelligent species is capable of doing (ie: dominating and inflicting tremendous pain/suffering and eating up all the species around us at unsustainable rates!) then perhaps its better that we don't have such intelligent species running amok all over the milky way, spreading pain, suffering and subjugation!

I'm still not entirely convinced that advanced intelligence in a species is actually a good survival strategy long-term ... a very popular support for the Fermi Paradox.

If we are alone then was NASA just being selfish when they decided to stop live video feeds from the shuttle missions?

Kangaroos did not evolve into intelligent beings because they did not have to. They are able to thrive in their enviroment. From what I can understand about our evolution, going back to our first bi-pedal ancestors, is that a physically weak and awkward species arose that had not alternative other than to use its brain to survive. Now with the brain being an attractive trait (much like that deer with the biggest antlers) intelligence began to be bread into us as a species.

If that species had developed with more natural tools to compete for food and what not, it is unlikely that we would be here today.

That being said I am sure, with the sheer number of worlds out there, that similar circumstances have occured else-where in the universe and possibly within our own galaxy.

lol good one John M! propaganda is everywhere now and days you woulda thought the year was 1984

There you go Dr. Going on to unintentionally prove that human intelligence came from the divine aka... God. Thanks

"but I thought that this conclusion (the one in the headline, that the presence of life is needed to maintain long-term habitability) was an obvious and already-established one. "

As I recall, the evolution simulation game SimEarth produced the same results - accidentally perhaps or as a reflection of the science at the time.

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