….due to the “Gaian bottleneck”, suggest ANU astrobiologists. Phys.Org takes up the story:

Life on other planets would likely be brief and become extinct very quickly, say astrobiologists from The Australian National University (ANU).

In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

“The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens,” said Dr Aditya Chopra from the ANU Research School of Earth Sciences and lead author on the paper, which is published in Astrobiology.

“Early life is fragile, so we believe it rarely evolves quickly enough to survive.”

“Most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable.”

About four billion years ago Earth, Venus and Mars may have all been habitable. However, a billion years or so after formation, Venus turned into a hothouse and Mars froze into an icebox.

Early microbial life on Venus and Mars, if there was any, failed to stabilise the rapidly changing environment, said co-author Associate Professor Charley Lineweaver from the ANU Planetary Science Institute.

“Life on Earth probably played a leading role in stabilising the planet’s climate,” he said.

Dr Chopra said their theory solved a puzzle.

“The mystery of why we haven’t yet found signs of aliens may have less to do with the likelihood of the origin of life or intelligence and have more to do with the rarity of the rapid emergence of biological regulation of feedback cycles on planetary surfaces,” he said.

….A plausible solution to Fermi’s paradox, say the researchers, is near universal early extinction, which they have named the Gaian Bottleneck.

“One intriguing prediction of the Gaian Bottleneck model is that the vast majority of fossils in the universe will be from extinct microbial life, not from multicellular species such as dinosaurs or humanoids that take billions of years to evolve,” said Associate Professor Lineweaver.

Read more at: http://phys.org/news/2016-01-aliens-silent-theyre-dead.html#jCp

And here’s their actual paper:

http://adi.life/pubs/ChopraLineweaver2016.pdf

Sounds reasonable. The confluence of factors that has made complex like on earth possible, including magnetic cores and hoovering planets and a tidal moon might be rare. Of course that just means we think they are important factors because we believe they are important to us, which may not be universal.

Bubblecar said:

Dr Chopra said their theory solved a puzzle.

Sheesh, we solved that so-called puzzle here ages ago.

The Rev Dodgson said:

Bubblecar said:

Dr Chopra said their theory solved a puzzle.

Sheesh, we solved that so-called puzzle here ages ago.

Go on, refresh our memories.

Bubblecar said:

The Rev Dodgson said:

Bubblecar said:

Dr Chopra said their theory solved a puzzle.

Sheesh, we solved that so-called puzzle here ages ago.

Go on, refresh our memories.

Well in addition to the high probability of suitable conditions not lasting long enough for complex life to evolve, we also have no idea how often life will evolve in the first place, and if it does how often it will evolve into complex lifeforms, even if suitable conditions do last long enough.

So if observations suggest that life is very rare, that’s not a puzzle, it just means it is rare because it doesn’t happen very often.

n=1

I imagine the number of favourable conditions for intelligent life to evolve is quite high and then for two of those intelligent lifeforms to met each other even more soon, you could be talking about a few thousands years time frame in the age of the universe before one or both civilisations dies.

Cymek said:

I imagine the number of favourable conditions for intelligent life to evolve is quite high and then for two of those intelligent lifeforms to met each other even more soon, you could be talking about a few thousands years time frame in the age of the universe before one or both civilisations dies.

intellient life hasn’t formed on earth.. what makes you think it would form elsewhere?…

stumpy_seahorse said:

Cymek said:

I imagine the number of favourable conditions for intelligent life to evolve is quite high and then for two of those intelligent lifeforms to met each other even more soon, you could be talking about a few thousands years time frame in the age of the universe before one or both civilisations dies.

intellient life hasn’t formed on earth.. what makes you think it would form elsewhere?…

True

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

They’re talking about early life. And we don’t know what the fate of life on Earth would have been had the planet been only fit for extremophiles throughout its existence.

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

Watch out for the black oil aliens

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

As far as we know it didn’t do to well on Venus or Mars though.

Also the things that survive really extreme conditions are pretty simple life forms. We don’t know how often these will evolve into complex multi-cellular life forms.

The Rev Dodgson said:

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

As far as we know it didn’t do to well on Venus or Mars though.

Also the things that survive really extreme conditions are pretty simple life forms. We don’t know how often these will evolve into complex multi-cellular life forms.

How well do extremophiles do in a less extreme environment, thrive or die

The Rev Dodgson said:

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

As far as we know it didn’t do to well on Venus or Mars though.

Also the things that survive really extreme conditions are pretty simple life forms. We don’t know how often these will evolve into complex multi-cellular life forms.

As an aside there is possibly complex and intelligent life but if it lives in a world that say could not support fire any intelligence would be restricted to rocks and the vegetation equivalent.

Bubblecar said:

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

They’re talking about early life. And we don’t know what the fate of life on Earth would have been had the planet been only fit for extremophiles throughout its existence.

There are only two limitations to life. One is the bottleneck in the development path towards the first bacteria. Probabilities of all the needed proteins and nucleic acids coming together in a neat package are horrifyingly small. The second is so-called intelligent life blowing the planet to hell.

AwesomeO said:

As an aside there is possibly complex and intelligent life but if it lives in a world that say could not support fire any intelligence would be restricted to rocks and the vegetation equivalent.

Intelligence is tightly rationed in life on Earth. Large brains require a lot of energy so have to be able to pay for their keep in terms of marked behavioural benefits to the organism.

mollwollfumble said:

There are only two limitations to life. One is the bottleneck in the development path towards the first bacteria. Probabilities of all the needed proteins and nucleic acids coming together in a neat package are horrifyingly small. The second is so-called intelligent life blowing the planet to hell.

Seems simplistic. There are many catastrophes that ostensibly habitable planets can face.

Humans could be an exception rather than the rule when it comes to tool using, civilisation creating intelligence. Aliens could be highly intelligent but content with a simplistic lifestyle.

mollwollfumble said:

There are only two limitations to life. One is the bottleneck in the development path towards the first bacteria. Probabilities of all the needed proteins and nucleic acids coming together in a neat package are horrifyingly small. The second is so-called intelligent life blowing the planet to hell.

That’s pure supposition.

We have almost zero evidence on the probability of bacteria evolving into complex life forms.

All we know is that on Earth it took a very long time.

Cymek said:

Humans could be an exception rather than the rule when it comes to tool using, civilisation creating intelligence. Aliens could be highly intelligent but content with a simplistic lifestyle.

Or bacteria.

The Rev Dodgson said:

Cymek said:

Humans could be an exception rather than the rule when it comes to tool using, civilisation creating intelligence. Aliens could be highly intelligent but content with a simplistic lifestyle.

Or bacteria.

That as well

The Rev Dodgson said:

mollwollfumble said:

>.In research aiming to understand how life might develop, the scientists realised new life would commonly die out due to runaway heating or cooling on their fledgling planets.

What rubbish. On Earth life has survived being buried in salt for 225 million years, has survived the entirety of the Earth’s oceans being frozen solid, has survived in oil reserves at a depth of many km beneath the surface, is virtually unaffected by being entombed 2 km down under the Antarctic ice cap, can even survive a trip to the Moon. A little heating or cooling isn’t going to affect its survival.

As far as we know it didn’t do to well on Venus or Mars though.

Also the things that survive really extreme conditions are pretty simple life forms. We don’t know how often these will evolve into complex multi-cellular life forms.

I think that’s rather the point. The authors seem to be making strong statements on weak evidence.

dv said:

I think that’s rather the point. The authors seem to be making strong statements on weak evidence.

They do eagerly invite criticism of the idea though, and have made the paper freely available for that purpose.

Bubblecar said:

They do eagerly invite criticism of the idea though

Well, I expect they’ll not be disappointed…

They’re talking about early life. And we don’t know what the fate of life on Earth would have been had the planet been only fit for extremophiles throughout its existence.

——

It was only fit for extremophiles for a very long time…

See Great Oxygenation Event

Ian said:

They’re talking about early life. And we don’t know what the fate of life on Earth would have been had the planet been only fit for extremophiles throughout its existence.

——

It was only fit for extremophiles for a very long time…

See Great Oxygenation Event

Yeah that’s an excellent read, I’ve read the book “Oxygen” years ago with the snowball earth theory, very interesting.