Fermi Paradox "Solved" - Are All the Aliens Dead?

Alien Life
Thursday, 21 January 2016 - 4:35PM

Are intelligent extraterrestrials radio silent because they're all dead? In new research published in Astrobiology, astronomers of The Australian National University put forward that young habitable planets can become unstable very quickly, turning a life-giving oasis into a hellish hothouse or frozen tundra faster than organisms can evolve. 

With all the stars and planets in our galaxy, and all the water and prebiotic chemicals that are known to exist, it is more than likely that other intelligent lifeforms are out there somewhere. But - there's still no sign of them. This mystery is known as the Fermi Paradox. 

"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, and have more to do with the rarity of the rapid emergence of biological regulation of feedback cycles on planetary surfaces," Dr. Aditya Chopra said in a statement.

Chopra and co-author Charley Lineweaver suggest that what they refer to in their paper as the "Gaian Bottleneck" could be a possible solution to the Fermi Paradox. If life isn't given a chance to stabilize its biosphere, then it's doomed.

"The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens," said Chopra. "Early life is fragile, so we believe it rarely evolves quickly enough to survive."

But, he continues, "Most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gasses 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, unlike Earth, most worlds fail to maintain this essential balance, ultimately succumbing to being cooked by a runaway greenhouse effect (like Venus), or frozen by a thinning atmosphere (like Mars).

"Life on Earth probably played a leading role in stabilizing the planet's climate," said Lineweaver. However, early microbial life on Venus and Mars, if it existed, was not fortunate or strong enough to win the race against environmental fluctuation, and become a stabilizing factor.

Of course, as we know, life on Earth was give this opportunity, and emerged from this bottleneck to form a symbiotic relationship with the planet we inhabit today. But now, humanity has inadvertently created a new bottleneck by causing irreversible negative changes to our delicate biosphere. Now, we're seeing rapid impacts on our civilization as balance in our climate is knocked off-kilter by the inexorable rise of greenhouse gases from industrial process and energy needs.

This raises the question- if an extraterrestrial life form survives the Gaian Bottleneck, does it then face another existential threat from its evolution into an industrial civilization? 

We probably wont know the answer until more data is collected - or provided to us by the life forms themselves. "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," theorizes Lineweaver. So, by studying space fossils, we could potentially test the validity of this hypothesis. 

But, for now, we're still stuck waiting for contact that may never come.