• We have updated the guidelines regarding posting political content: please see the stickied thread on Website Issues.

Superhabitable Exoplanets (Even More Life-Friendly Than Earth)

EnolaGaia

I knew the job was dangerous when I took it ...
(ACCOUNT RETIRED)
Joined
Jul 19, 2004
Messages
29,622
Location
Out of Bounds
pissoffpangloss.jpg

In searching for exoplanets that may harbor life we've been biased toward planets which are the most similar to our earth. The fact that our earth hosts life as we know it doesn't necessarily mean earth is optimal for life. Newly published research identifies a couple of dozen known exoplanets that are arguably more conducive to life than our own.
Some Planets May Be Better for Life Than Earth: Researchers Identify 24 Superhabitable Exoplanets

Earth is not necessarily the best planet in the universe. Researchers have identified two dozen planets outside our solar system that may have conditions more suitable for life than our own. Some of these orbit stars that may be better than even our sun.

A study led by Washington State University scientist Dirk Schulze-Makuch recently published in the journal Astrobiology details characteristics of potential “superhabitable” planets, that include those that are older, a little larger, slightly warmer and possibly wetter than Earth. Life could also more easily thrive on planets that circle more slowly changing stars with longer lifespans than our sun.

The 24 top contenders for superhabitable planets are all more than 100 light years away, but Schulze-Makuch said the study could help focus future observation efforts ...

“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.” ...

Habitability does not mean these planets definitely have life, merely the conditions that would be conducive to life. ...

“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.” ...

FULL STORY: https://scitechdaily.com/some-plane...rchers-identify-24-superhabitable-exoplanets/
 
According to the article cited above these are some of the criteria the researchers used to characterize exoplanets as superhabitable ...

The researchers selected planet-star systems with probable terrestrial planets orbiting within the host star’s liquid water habitable zone ...

While the sun is the center of our solar system, it has a relatively short lifespan of less than 10 billion years. Since it took nearly 4 billion years before any form of complex life appeared on Earth, many similar stars to our sun, called G stars, might run out of fuel before complex life can develop.

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. K stars have the advantage of long lifespans of 20 billion to 70 billion years. This would allow orbiting planets to be older as well as giving life more time to advance to the complexity currently found on Earth. ...

planets should not be so old that they have exhausted their geothermal heat and lack protective geomagnetic fields. Earth is around 4.5 billion years old, but the researchers argue that the sweet spot for life is a planet that is between 5 billion to 8 billion years old. ...

A planet that is 10% larger than the Earth should have more habitable land. One that is about 1.5 times Earth’s mass would be expected to retain its interior heating through radioactive decay longer and would also have a stronger gravity to retain an atmosphere over a longer time period. ...

Water is key to life and the authors argue that a little more of it would help, especially in the form of moisture, clouds and humidity. A slightly overall warmer temperature, a mean surface temperature of about 5 degrees Celsius (or about 8 degrees Fahrenheit) greater than Earth, together with the additional moisture, would be also better for life. This warmth and moisture preference is seen on Earth with the greater biodiversity in tropical rain forests than in colder, drier areas. ...
 
Here are the bibliographic details, abstract and access link for the published superhabitable exoplanets research report.

In Search for a Planet Better than Earth: Top Contenders for a Superhabitable World
Dirk Schulze-Makuch, René Heller, and Edward Guinan
Astrobiology
Published Online:18 Sep 2020
https://doi.org/10.1089/ast.2019.2161

Abstract
The fact that Earth is teeming with life makes it appear odd to ask whether there could be other planets in our galaxy that may be even more suitable for life. Neglecting this possible class of “superhabitable” planets, however, could be considered anthropocentric and geocentric biases. Most important from the perspective of an observer searching for extrasolar life is that such a search might be executed most effectively with a focus on superhabitable planets instead of Earth-like planets. We argue that there could be regions of astrophysical parameter space of star-planet systems that could allow for planets to be even better for life than our Earth. We aim to identify those parameters and their optimal ranges, some of which are astrophysically motivated, whereas others are based on the varying habitability of the natural history of our planet. Some of these conditions are far from being observationally testable on planets outside the solar system. Still, we can distill a short list of 24 top contenders among the >4000 exoplanets known today that could be candidates for a superhabitable planet. In fact, we argue that, with regard to the search for extrasolar life, potentially superhabitable planets may deserve higher priority for follow-up observations than most Earth-like planets.

FULL PAPER:
https://www.liebertpub.com/doi/10.1089/ast.2019.2161
 
None of these superhabitable worlds have been found for certain yet, but I'm sure they exist.

If tidally-locked worlds are also capable of supporting life, then a selection of planets orbiting red dwarfs may become even more superhabitable in the future (hyperhabitable?). Certain red dwarf planets might remain habitable for hundreds of billions of years.
 
There is a planet I know. Its called Thalassa.

It is over seventy percent liquid water.

And yes, it is teeming with life unimaginable here.
 
Back
Top