The past couple of years have been eventful ones for those with an interest in habitable extrasolar planets. The media has been filled with stories about the discovery of many new extrasolar planets that have been billed as being “potentially habitable”. Unfortunately follow-up observations and new insights into the properties of planets larger than the Earth have cast doubts on some of these initial optimistic proclamations that have been largely ignored by the media and other outlets. With all the new information available, I figured it was a good time to make an objective reevaluation of the potential habitability of a number of extrasolar planets that have made the headlines in recent years.
In my first article of the New Year for Centauri Dreams, titled “A Review of the Best Habitable Planets Candidates”, I review each one of the 29 potentially habitable planets listed in the well-regarded “Habitable Exoplanets Catalog” web site maintained by the University of Puerto Rico at Arecibo Planetary Habitability Laboratory. Using the latest data on these worlds combined with our best current understanding of planetary habitability and the mass-radius relationship of extrasolar planets larger than the Earth, I present the case that the potential habitability of the majority of these worlds has been overstated by the media and others. In reality, there are maybe three good candidates for potentially habitable planets currently known with only a few additional ones worthy of additional consideration.
While this conclusion may come as a disappointment to those interested in habitable extrasolar planets, it should be remembered that the search for such worlds has only just begun. There are more Kepler planet candidates currently being studied that are sure to expand this list in the near future including potentially habitable planets not much larger than the Earth orbiting Sun-like stars (see “Earth Twins on the Horizon?” and “First Look at Kepler’s Complete Primary Mission Data Set“).
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Related Reading
“A Review of the Best Habitable Planets Candidates”, Centauri Dreams, January 30, 2015 [Post]
“First Look at Kepler’s Complete Primary Mission Data Set”, Drew Ex Machina, January 26, 2015 [Post]
“Habitable Planet Reality Check: Kepler’s New K2 Finds”, Drew Ex Machina, January 20, 2015 [Post]
“Earth Twins on the Horizon?”, Drew Ex Machina, January 9, 2015 [Post]
“Habitable Planet Reality Check: 8 New Habitable Zone Planets”, Drew Ex Machina, January 8, 2015 [Post]
“The Composition of Super-Earths”, Drew Ex Machina, January 3, 2015 [Post]
“The Transition from Rocky to Non-Rocky Planets”, Centauri Dreams, November 14, 2014 [Post]
“Habitable Planet Reality Check: GJ 667C”, Drew Ex Machina, September 7, 2014 [Post]
“Habitable Planet Reality Check: Terrestrial Planet Size Limit”, Drew Ex Machina, July 24, 2014 [Post]
“The Disappearing Habitable Planets of GJ 581”, Drew Ex Machina, July 7, 2014 [Post]
“GJ 832c: Habitable Super-Earth or Super-Venus”, Drew Ex Machina, June 27, 2014 [Post]
“Habitable Planet Reality Check: Kapteyn b”, Drew Ex Machina, June 6, 2014 [Post]
“Habitable Planet Reality Check: Kepler 186f”, Drew Ex Machina, April 20, 2014 [Post]