We should be open-minded about where we look for alien life, suggests a recent paper.
A study published in the Journal Nature Astronomy reveals that rocky alien worlds with a thick atmosphere of hydrogen and helium are likely to be habitable for billions of years, especially if they have a temperate climate and liquid water.
Water is the basis for life on Earth. In this light, the search for extraterrestrial life has typically focused on exploring worlds with liquid water on their surfaces, known as habitable worlds. However, in addition to this requirement, scientists remain unsure of the extent to which exoplanets must resemble Earth to support life. Earlier studies of distant worlds suggest that many planetary systems differ from ours.
The Earth’s solar system contains no super-Earths, which are rocky planets up to 10 times as massive as the Earth. Nonetheless, these planets appear to be common in other star systems across the galaxy.
“The exoplanets we detect are very different from the planets in our solar system, and that’s a good argument for continuing to think outside the box when it comes to habitability,” revealed study lead author Marit Mol Lous, an exoplanet researcher at the University of Zurich in an interview with space.com.
The researchers explored the possibility of life on Super-Earths in the new study. So far, astronomers have only observed them orbiting near their stars because that is where they can be easily observed.
Although this is the case, previous computer models suggest some Super-Earths could orbit much farther from their stars. Hydrogen and helium, once the primary ingredients of their planetary systems, may remain on super-Earths that are distant from their stars.
In the universe, hydrogen and helium comprise 99.9% of the ordinary matter; however, nearby Super-Earths would be vaporized by a star’s heat, but Super-Earths farther from the star will have a primordial atmosphere.
Using the new study, the researchers aimed to determine whether a planet engulfed in the gases could be habitable.
Scientists say that if such a planet has a large atmosphere, its hydrogen could act as a greenhouse gas, capturing the star’s heat regardless of its distance from the star.
Researchers created computer simulations of super-Earths with atmospheres composed of hydrogen and helium orbiting Sun-like stars at distances of 1 to 100 astronomical units (AUs; one AU is the distance between Earth and the sun, which is approximately 93 million miles or 150 million kilometers).
Researchers reported finding Super-Earths with distances greater than 2 AU could harbor temperate conditions and liquid water for up to 8 billion years.
These findings suggest that “exotic habitats should also be considered when investigating habitability on other planets,” Mol Lous said.
Even if these super-Earths become wanderers — rogue planets — and rove across space without being attached to any star, they could still be habitable.
Several recent studies suggest that free-roaming planets may be common and colonizing civilizations may use them as ships. Studies have suggested that, in our galaxy alone, there could be more than 50 billion rogue planets, wandering through the vastness of space.
Scientists revealed that many Super-Earths cloaked in hydrogen and helium are too hot to contain liquid water shortly after forming; however, rogue Super-Earths with atmospheres about 10,000 times as massive as Earth’s could eventually cool enough to contain water for more than 50 billion years if they have atmospheres about five times as massive as Earth’s.
It is unlikely that you will be able to walk around these planets. Mol Lous concluded that the atmospheres on these worlds are 100 to 1,000 times thicker than Earth’s, which would translate into “roughly 100 to 1,000 times the pressure on our planet’s surface.”.
“They are comparable to what we find in the deep ocean.”
While the study certainly raises the chances of discovering life –even perhaps evolved life– everything at this point is a theory until we do discover such a distant Super-Earth, and point our most powerful telescopes toward it.
Luckily for scientists, the James Webb Space Telescope is ready, and the data it will gather in the near future could help scientists better understand the habitability of such exoplanets.
Furthermore, the Nancy Grace Roman Space Telescope is set for launch in 2027, so astronomers will be able to search for exoplanets not only using the transit method but also gravitational microlensing.
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