NASA spots two potentially life-supporting alien planets

Two freshly-identified planets could feasibly support life, NASA's Jet Propulsion Lab has concluded, the latest crop of Earth-like possibilities spotted by the Kepler Space Telescope. Though 181 light years away from our own Earth, the two new discoveries are half of a quartet of "promising" planets that could be rocky, among other life-sustaining criteria.

Ranging in size from 20- to 50-percent larger than Earth, while two of the four are believed to be hotter than suitable for sustaining life – at least as we know it currently -0 the other two are within the limits of water being liquid.

The star itself is an M dwarf, dubbed K2-72, and it's K2-72c and K2-72e which have scientists at JPL excited. The former is believed to around 10-percent warmer than Earth is typically, while the latter is around 6-percent cooler.

Even with the similarities, were there life on the planets it would have a very different experience to conditions on Earth. For a start, K2-72 is dimmer than our sun, being less than half its size: that means its habitable zone, the band around the star within which conditions are potentially conducive to life, is much closer and thus orbits much faster.

In fact, the orbital periods range from as little as 5.5 days to 24 days. K2-72c's equivalent of our year lasts around 15 days, while K2-72e's is around 24 days.

They're the latest findings of the Kepler telescope, which is now around three years into its K2 mission. Scientists were forced to come up with a workaround after the stabilization mechanisms of the brightness-tracking system broke down, imaginatively using solar pressure from the sun itself to hold the telescope in place.

Once identified by K2, potentially interesting planets are captured in high-resolution, while optical spectroscopy is used to figure out the physical properties of the stars they orbit. From that, calculations about the planet's mass, radius, and temperature can be made.

Next up, meanwhile, will be the James Webb Space Telescope, currently being assembled, and which will offer a far closer view of the atmospheres around candidate planets.

The new telescope is expected to launch in 2018, and cost around $8.8bn when complete.