Canadian Astrophysicist Say There Are Even More Superhabitable Worlds Than Once Thought

Scientist Discover More Life Hospitable Planets Than Previously Imagined

The latest issue of the peer-reviewed journal known as Astrobiology challenges the conventional wisdom regarding life on other planets. It has long been believed that for a planet to sustain intelligent life, it would need to be similarly distanced from a sun as is our planet. Now, astrophysicist René Heller from McMasters University and John Armstrong of Weber State University have put forth a different take on the matter.

The two argue in their article entitled “Superhabitable Worlds” that scientists should also look at other spheres that are not like Earth, but which can offer life sustaining conditions that in some cases they argue might be more favorable to evolution. If their premise is sound, the conclusion will be to open up a much wider range of locations where life can be found. The two contend that even moons might be found to contain life.

According to their paper:

To be habitable, a world (planet or moon) does not need to be located in the stellar habitable zone (HZ), and worlds in the HZ are not necessarily habitable. Here, we illustrate how tidal heating can render terrestrial or icy worlds habitable beyond the stellar HZ. Scientists have developed a language that neglects the possible existence of worlds that offer more benign environments to life than Earth does. We call these objects “superhabitable” and discuss in which contexts this term could be used, that is to say, which worlds tend to be more habitable than Earth. In an appendix, we show why the principle of mediocracy cannot be used to logically explain why Earth should be a particularly habitable planet or why other inhabited worlds should be Earth-like.

“Our argumentation can be understood as a refutation of the Rare Earth hypothesis. Ward and Brownlee (2000) claimed that the emergence of life required an extremely unlikely interplay of conditions on Earth, and they concluded that complex life would be a very unlikely phenomenon in the Universe,” stated the authors in their paper “Superhabitable Worlds.”

In their estimation, Alpha Centauri B, which is the closest star to our world after the sun, can sustain life for planets in its sphere of influence over what they believe is a period of 10 billion years. Put another way, scientists believe Earth has been in existence for 3.5 billion years and may have another 2 billion left before it can no longer sustain life.

“While we agree that the occurrence of another truly Earth-like planet is trivially impossible, we hold that this argument does not constrain the emergence of other inhabited planets. We argue here in the opposite direction and claim that Earth could turn out to be a marginally habitable world. In our view, a variety of processes exists that can make environmental conditions on a planet or moon more benign to life than is the case on Earth.”

On The Web:
More life-friendly planets out there than previously imagined
http://www.thespec.com/news-story/4352955-more-life-friendly-planets-out-there-than-previously-imagined/

Superhabitable Worlds
http://online.liebertpub.com/doi/abs/10.1089/ast.2013.1088