In new research published in the journal Astrobiology, astronomers of The Australian National University (ANU) pondered this scenario and realized that young habitable planets can become unstable very quickly. What once was a life-giving oasis becomes a hellish hothouse or frozen wasteland very quickly.
“The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens,” said Aditya Chopra, lead author of the paper. “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,” he said.
Unlike Earth, most worlds will likely not find this balance, ultimately succumbing to being cooked by a runaway greenhouse effect (like Venus) or frozen by a thinning atmosphere (like Mars). Life will often not be fortunate enough to win the race against environmental fluctuations to become a stabilizing factor.