NASA's dedicated exoplanet hunter, the Kepler space telescope, has turned up five new planets. One of the planets is bigger than Jupiter but as light as styrofoam, and the findings only get crazier.
All five of the exoplanets are bigger than Earth, and four of them are significantly bigger than Jupiter. As the diagram up top indicates, all five are hotter than molten lava, and two of them are even hotter than the melting point of iron. Indeed, those two planets are actually hotter than the stars they orbit, which is completely unprecedented. The planets also have incredibly quick orbits, with some taking as little as three to five days to complete a revolution around their star.
The low densities of the planets has been of considerable interest to astronomers. The four massive exoplanets are much lighter than Jupiter, including one whose amazingly low density has given it the nickname "Styrofoam World." It looks like this kind of ultra low density planet might actually be the norm, with our solar system's denser gas giants being the exception. However, the process that would create such planets is still unknown.
Taken together, all of this pretty much rules out any chance of life on these planets. But some of Kepler's other data is more promising on that score, as it has already detected dozens of Sun-like twins, suggesting the average star in the galaxy is similar to our own in terms of size and stability. That bodes well for the chances of finding an Earth-like exoplanet in the near future, and there is still months' worth of Kepler data for astronomers to pore through.
Styrofoam planet photo via Becca Elpy.