After a few billion years, the water in the Earth’s oceans will evaporate, the atmosphere will burn out, and our Sun will turn into a red giant. It will be a real end for all life on Earth, but on the outer borders of the solar system the most interesting things are just beginning. Europe and Enceladus will turn into satellites with liquid oceans, offering shelter to any posthuman life forms that can escape from the planet’s covered with hot lava.
This is at least one of the possible scenarios for our species and its life in the solar system, according to the new computer models developed by astronomers Ramses Ramirez and Lisa Kaltenagger, details of which were recently published in the journal Astrophysical Journal. The key conclusion of this study, which states that both of these icy moons can become inhabited as soon as the Sun grows old and grows in size, could be one explanation for where else in the galaxy we could find life.
“We know that in the future our Sun will become too hot and bright for life on Earth. Science fiction often considers the option of people moving to Mars and other planets. Now we know where to go, ”says Kaltenagger.
This study not only examines the possibility of humanity’s migration to more distant orbits with the aging of the Sun, but also hints that any possible life imprisoned in the ice captivity of satellites may finally, in five billion years, seem to everyone’s eyes.
Until today, astronomers interested in discovering inhabited worlds outside the solar system have closely followed only those planets and stars that were most similar to the Earth and the Sun. In other words, we are talking about small, rocky worlds located in the so-called habitable zones of those stars whose core burns hydrogen. As soon as the stars run out of hydrogen fuel, they do not die, but rather go into a different state, changing essentially only their type. Our Sun, for example, with time, or rather after about five billion years, will move into the phase of the red giant, turning everything with it, from Mercury to Mars, to ashes.
If you look at it from the position of the Earth, then all this, of course, is very sad - hardly news of the apocalypse will please anyone. However, despite the fact that the inner region of the solar system will turn into burnt coals, more remote areas located near the outer border will become more suitable for living. The same variant of the evolution of the habitable zone may concern the whole of our galaxy, if we consider that all the stars in its center will also enter the phase of red giants over time.
The boundaries of the habitable zone now and in the future (marked in green) according to the new models of Ramirez and Kaltenagger
All this leads to the question: can the red giants and their developed inhabited zones support the existence of life?
To find out, Ramirez and Kaltenagger created models of different habitable zones, which would be characteristic of stars of different sizes, and their transition into the phase of red giants. It is logical to assume that with an increase in the size of the star, the borders of the habitable zone increase, or rather move. However, the key question here is how long the habitable zone will be maintained during the phase of the red giant. And the answer to this question has already been found. It turns out that everything will depend on the mass of the initial sequence of this star.
According to a new study, the habitat zone of the red giant inside our solar system will exist for about 500 million years. However, the original stars with a smaller mass can maintain the conditions of the inhabited zone of the phase of red giants up to 9 billion years. And this is even more than the history of our entire solar system.
“It actually destroys the idea that only systems with the same stars as our Sun and the same age as the sun can be considered habitable,” says Kaltenagger.
“We essentially provide observers with a navigational map of the habitable zone for all types of stars,” agrees Ramirez and adds: “This is actually a tool for searching all potentially habitable planets.”
Recently, the ice satellites Europe and Enceladus are increasingly being considered by scientists as the most likely bastions for extraterrestrial life. Both moons have a hot and hard core. And in the case of Enceladus, scientists generally have quite convincing evidence that there is an entire world ocean under its surface. The most interesting thing in the new study lies in the subtext, according to which such frozen worlds as Enceladus may, in the distant future, become a real water paradise. By that time, any life forms that are enclosed deep in the ocean depths, closer to warm sources, can come to the surface and create an earth-like biosphere that will become quite noticeable for alien astronomers.
Whatever it was, but we will not be able to personally know this in relation to the Solar System soon. However, the planets and their satellites orbiting the red giants at the moment can give us some clues. To date, astronomers are aware of 23 red giants located within a radius of 100 light years from Earth, as well as about a hundred other stars that are approaching the phase of red giants.
“It will be surprising to find signs of life in a world that has always been known to us as an icy desert, but is now inside an evolved habitable zone,” says Kaltenagger.
“This, no doubt, would help to find the answer to the question of whether the existence of life in the subsurface ocean is possible. No matter what we find on Europe or Enceladus, this find will be a very interesting and important part of a common mystery. ”
Of course, by the time the outer boundaries of the solar system become habitable, our descendants may already live and exist as entities inside some cloud server within the Dyson sphere, which has grown into half galaxies. Who knows, maybe on Earth by that moment there will be a few residents waiting for the most suitable moment to launch their luxury yachts into the waters of Europe.
One thing is clear that life will probably have many options for further development and existence even after our disappearance.
The article is based on materials .
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