Earth is not necessarily the best planet in the universe. Investigators have identified two dozen planets beyond our solar system which might have conditions more suitable for life compared to our own. A few of those orbit suns that might be better than even our sun.
Details characteristics of possible”superhabitable” planets, including the ones that are older, somewhat bigger, somewhat warmer and potentially wetter than Earth. Life could also more readily flourish on planets which circle more gradually changing stars with longer lifespans than our sun.
The 24 top contenders for superhabitable planets are more than 100 light years away.
“With the next space telescopes coming up, we will get more information, so it is important to select some targets,” said Schulze-Makuch, a professor with WSU and the Technical University in Berlin. “We have to focus on certain planets that have the most promising conditions for complex life. However, we have to be careful to not get stuck looking for a second Earth because there could be planets that might be more suitable for life than ours.”
For the analysis, Schulze-Makuch, a geobiologist with experience in planetary habitability does not indicate these planets definitely have life, only the conditions that would be suitable for life.
While the sun is the middle of our solar system, it has a comparatively short lifespan of over 10 billion years. Since it took nearly 4 billion years prior to any form of complex life appeared on Earth, lots of similar stars to our sun, known as G stars, might run out of light before complex life can grow.
In addition to looking at systems with cooler G stars, the researchers also looked at systems with K dwarf stars, which are somewhat cooler, less massive and less luminous than our sun. The researchers also looked at systems with K dwarf stars, which are somewhat cooler, less massive and less luminous than our sun.
But to be habitable, planets shouldn’t be so old they have exhausted their geothermal heat and lack protective geomagnetic fields.
Mass and size also matter. One which is roughly 1.5 times Earth’s mass would be expected to retain its inside heating through radioactive decay longer and would likewise have a more powerful gravity to retain an atmosphere within a longer period of time.
Water is key to life and the authors assert that a little more of it would help, especially in the form of moisture, clouds and humidity.
A marginally overall warmer temperatures, an average surface temperature of approximately 5 degrees Celsius (or about 8 degrees Fahrenheit) higher than Earth, together with the further moisture, could be also more suitable for life.
Among the 24 top planet candidates none of these meet all the standards for superhabitable planets, but one has four of the critical characteristics, which makes it possibly a great deal more suitable for life than our home planet.
“It’s sometimes difficult to convey this principle of superhabitable planets because we think we have the best planet,” said Schulze-Makuch. “We have a great number of complex and diverse lifeforms, and many that can survive in extreme environments. It is good to have adaptable life, but that doesn’t mean that we have the best of everything.”
Related Journal Article: https://www.liebertpub.com/doi/10.1089/ast.2019.2161