Civilizations can colonize other worlds even without spacecraft capable of flying between the stars. Instead, they can use orphan planets traveling through their star systems.
How orphan planets will help travel the Galaxy
Even if an extraterrestrial civilization does not have spacecraft capable of traveling the distances between the stars, this does not mean that it will stay on its planet until it perishes in the fire of its Sun. It is enough to be able to travel between planets and wait for a space traveler who will throw living beings to their new home.
An article about this was recently published in the International Journal of Astrobiology. In it, scientists advise to turn their attention to orphan planets. These Earth-like objects form far from stars or are ejected from their systems in the early stages of evolution. They fly freely in space, and for hundreds of millions of years they fly past numerous luminaries.
And it is they who are proposed to be used as transport. An extraterrestrial civilization could build domed cities on their surface and build nuclear reactors. Thus, if not biological beings, then intelligent machines created by them can get into other worlds.
How long will the journey last
At the same time, it should be remembered that the orphan planet cannot support life, even if they are similar to Earth in their chemical composition. Without sunlight, all the water on their surface will freeze. So, as soon as such an object reaches another system, it is worth getting off it.
However, it should be noted that traveling on an orphan planet can take a long time. The speed of such objects in relation to the stars is measured in tens and hundreds of kilometers per second. And the distances between the stars are measured in light years. So, the flight will last hundreds of thousands, or even millions of years.
Using Ice Dwarfs
An alternative to orphan planets can be ice dwarfs, similar to Pluto and Sedna in the solar system. They also have significant reserves of frozen water. They may well act as a “lifeboat” if the host dawn reaches the final stage of its existence and begins to turn into a red giant.
Scientists expect that in this case, the explosive wave can give them enough acceleration to overcome the force of gravity and become space travelers. In all other respects, such a journey will be similar to an orphan planet with the difference that passengers will not be able to choose a route.
How to find orphan planets where aliens travel
According to the authors of the study, orphan planets, which are a vehicle for other civilizations, can be detected even by modern means. They should have so-called technomarkers, in particular, emit very unusual electromagnetic waves, familiar to us from the work of our machines.
However, such radiation can be short-lived. In particular, the signal “Wow!”, recorded in 1977, is known to be such a technomarker. However, if it really comes from an orphan planet, it will be very difficult to find it.
According to phys.org
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