Usually when NASA scientists report on new planets, they talk about one or two. However, on February 26th, the US Space Agency stunned space lovers when they announced the discovery of 715 new worlds, almost doubling the size the galaxy, which had previously been thought to have comprised of 961 planets.

What's even more interesting is that they share between them just 305 stars, which means that many are part of a multi-planetary system similar to that of our solar system. Of the 715, scientists are most intrigued by four. Less than 2.5 times the size of earth, they orbit in their sun's habitable zone. That means that like earth, they are at a safe distance from their stars to sport a temperature that may support liquid water. This of course raises the possibility of the planets being able to sustain life.

One of the four that the scientists call Kepler-29f, is orbiting a star that is half the size and 5% brighter than our sun. The planet itself appears to be twice the size of the earth. What the scientists still need to verify is whether it is a giant gaseous world that is surrounded by a hydrogen-helium envelope or a water world that is surrounded by a deep ocean.

While the planet discovery was announced recently, they were part of the thousands detected as 'planet candidates' by the Kepler Space Observatory between 2009 and 2011. The reason it took the scientists so long to confirm was because until recently, they had been using a laborious process that allowed them to verify only one planet at a time.

Therefore, until February 25th, Kepler was being credited with having found just 246 of 961 planets that were known to exist. However, a team led by Jack Lissauer, planetary scientist at NASA's Ames Research Center in Sunnyvale, Calif, has come up with a much more efficient process to identify multiple planets by seeking out their stars. This means that going forward, three-digit discoveries like the most recent one, may become more the norm than the exception.

Launched by NASA is 2009, the Kepler Space Observatory's mission was to locate planets that lie in 'goldilocks' or 'habitable' zones - where the planet is neither too close to its star, nor too far away. During its five-year tenure, the telescope surveyed over 150,000 stars and located more than 3,600 planet candidates. Unfortunately, this prolific $600 million USD exoplanet detector had to be decommissioned in 2013, when two of its four gyroscope-like reaction wheels that kept it pointed in the right direction failed. But it has left behind enough potential new worlds for Jack Lissauer and his team to discover, for many years - So stay tuned!

Resources: NASA.gov, dailymail.co.uk

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