Massachusetts Institute of Technology | 2014 Dec 17
Nearly 2,000 planets beyond our solar system have been identified to date. Whether any of these exoplanets are hospitable to life depends on a number of criteria. Among these, scientists have thought, is a planet’s obliquity — the angle of its axis relative to its orbit around a star.
Earth, for instance, has a relatively low obliquity, rotating around an axis that is nearly perpendicular to the plane of its orbit around the sun. Scientists suspect, however, that exoplanets may exhibit a host of obliquities, resembling anything from a vertical spinning top to a horizontal rotisserie. The more extreme the tilt, the less habitable a planet may be — or so the thinking has gone.
Now scientists at MIT have found that even a high-obliquity planet, with a nearly horizontal axis, could potentially support life, so long as the planet were completely covered by an ocean. In fact, even a shallow ocean, about 50 meters deep, would be enough to keep such a planet at relatively comfortable temperatures, averaging around 60 degrees Fahrenheit year-round. ...
Climate at high-obliquity - David Ferreira et al
- Icarus 243 236 (15 Nov 2014) DOI: 10.1016/j.icarus.2014.09.015