Pebbles In The Sky

blue-alien-womanNASA’s Kepler space telescope has discovered two more possibly life-bearing planets – that is, planet’s in their sun’s habitable zone.  Excerpt:

NASA’s Kepler space telescope has spotted four possibly rocky alien planets orbiting the same star, and two of these newfound worlds might be capable of supporting life.

The four exoplanets circle a red dwarf — a star smaller and dimmer than the sun — called K2-72, which lies 181 light-years from Earth in the Aquarius constellation. All four worlds are between 20 percent and 50 percent wider than Earth, making them good candidates to be rocky, discovery team members said.

Two of the four planets, known as K2-72c and K2-72e, appear to be in the star’s “habitable zone” — that just-right range of distances at which liquid water can exist on a world’s surface, the scientists added.

Here’s what would make life weird for any possible colonists on those worlds:

Because K2-72 is a red dwarf, its habitable zone is much closer in than that of the sun. For example, K2-72c completes one orbit every 15 Earth days, yet it is likely just 10 percent warmer than our planet. K2-72e has a 24-Earth-day year, and it’s about 6 percent colder than Earth, the scientists said. (All four newfound planets complete an orbit in 24 Earth days or less, making them closer to K2-72 than Mercury is to the sun.)

Imagine living with a 15-day year!  There is no information in the article as to how long each world’s day is, but at this distance from their sun it’s reasonable to assume that both may be tidally locked, as the Moon is to Earth – meaning that the concept of a “day” may not be meaningful, as the planets would only show one face to the sun.  It would also mean that the actual habitable area of each world would probably be limited to a band around the day-night line.

Interesting stuff.  Astronomers are discovering new exoplanets almost weekly now.  The universe is a more interesting place than we had reason to imagine just a few short years ago.

Space Chick