Everything in the universe comes to an end, and our sun is no exception. In five billion years from now, the sun will become a huge orange giant star, so large that it will engulf the orbits of Mercury and Venus.
In this dramatic process, the Earth will not survive the sun’s expansion, it will no longer be within the habitable zone. It’ll be the end for life on Earth but don’t worry, our solar system could give us a second chance.
In the new paper published in Astrophysical Journal, astronomers Ramses Ramirez and Lisa Kaltenegger, from Cornell’s Carl Sagan Institute, suggest that when giant stars begin to die out, they could warm up frozen planets enough to have liquid water on their surface.
When a star ages and brightens, the habitable zone moves outward and you’re basically giving a second wind to a planetary system,
said lead author Ramirez.
Currently objects in these outer regions are frozen in our own solar system, and Europa and Enceladus — moons orbiting Jupiter and Saturn — are icy for now.
Long after our own plain yellow Sun expands to become a red giant star and turns Earth into a sizzling hot wasteland, there will still be regions in our solar system — and other solar systems as well — where life might thrive,
Red giant stars demise is a New Beginning
Some red giant stars, smaller mass stars, in the universe remain that way for billions of years, in some cases, they still red giants even 9 billion years; so planets can remain habitable around these stars twice Earth’s current age. That’s sufficiently long for life to form from scratch, or to flourish in a newer, more welcoming environment.
This is basically breaking the idea that habitable means stars like our own, and suns with ages like our own,
We’re basically providing observers with a navigational map of the habitable zone for any star,” he said. “It’s a tool for finding all potentially habitable planets.
In the far future, a distant frozen world like Saturn’ moon Enceladus could become habitable around our suns for billions of years, maybe even starting life, just like on Earth. That makes me very optimistic about the chances for life in the long run,
In their study, the team has already identified 23 red giant stars within 100 light-years of Earth, and a hundred more that are close to the red giant phase; which could be warming up new habitats for life as we speak.
It would be fascinating to discover signatures of a life on a world that we knew had to be completely frozen initially, but that is now within the evolved habitable zone,
That would, in a way, help answer the question of whether you could have life in a subsurface ocean. No matter what we find on Europa and Enceladus, it’ll be a really interesting part of the puzzle.