Earlier this month, NASA’s Kepler mission found its first star orbiting in a habitable zone around a sun similar to our own. This is another important discovery because as we know and as I have pointed out before, any planet that can be found within the habitable, or “Goldilocks zone,” as it is otherwise called, has the potential to support life (as long as water is also present).

According to the article:

The planet is about 2.4 times the radius of Earth. Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.

Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive. Two other small planets orbiting stars smaller and cooler than our sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars.

“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. “Kepler’s results continue to demonstrate the importance of NASA’s science missions, which aim to answer some of the biggest questions about our place in the universe.”

Kepler discovers planets and planet candidates by measuring dips in the brightness of more than 150,000 stars to search for planets that cross in front, or “transit,” the stars. Kepler requires at least three transits to verify a signal as a planet.

“Fortune smiled upon us with the detection of this planet,” said William Borucki, Kepler principal investigator at NASA Ames Research Center at Moffett Field, Calif., who led the team that discovered Kepler-22b. “The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season.”

Here are a couple illustrations of the planet and its orbit:

Credit: NASA/Ames/JPL-Caltech - This artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star.

Credit: NASA/Ames/JPL-Caltech - This diagram compares our own solar system to Kepler-22, a star system containing the first "habitable zone" planet discovered by NASA's Kepler mission.

Scientists have discovered evidence of pockets of ice on the Jupiter moon, Europa, which is further acknowledgment that life most likely exists, in some form, elsewhere in the universe, since, as we know, the presence of water is a basic necessity for the development of biological life. And I have pointed out numerous instances on this blog in which water or ice particles have been found elsewhere in the cosmos. Presumably, it’s only a matter of time before life is found somewhere other than earth, even if that life consists of only simple microorganisms.

In this photo is pictured the Conamara Chaos region of Europa:

Credit: NASA, JPL, UNIV. OF ARIZONA/Jumbled icy patches on Jupiter’s moon Europa, like the Conamara Chaos region pictured here, may indicate the presence of large liquid reservoirs a few kilometers beneath the surface.