300 Million Potentially Habitable Earths

• 07 Nov 2020

Why in News

New analysis of data from Kepler Spacecraft shows a large number of habitable Exoplanets.

• An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmation of detection of exoplanets occurred in 1992.

Key Points

• After analysing Kepler's data for two years, a team from National Aeronautics and Space Administration (NASA) estimated that there are at least 100 billion stars in the Milky Way, of which about 4 billion are sunlike.
• If only 7% of those stars have habitable planets, a conservative estimate is that there could be as many as 300 million potentially habitable Earths (exoplanets) out there in the whole Milky Way alone.
• The team calculated that at least one third of stars similar in mass and brightness to the sun have rocks like earth in their habitable zone.

Kepler Spacecraft

• The Kepler mission was named in honor of 17^th-century German astronomer Johannes Kepler, who discovered the laws of planetary motion.
• The Kepler Mission was launched in 2009 on a three-and-a-half year mission to monitor 1,50,000 stars in a patch of sky in the Milky Way.
• It was NASA’s first planet-hunting mission, it discovered more than 2,600 of around 3,800 exoplanets.
  
  • It looked for tiny dips in starlight caused by an exoplanet passing in front of its home star.
• Kepler’s formal goal was to measure a number called eta-Earth: the fraction of sunlike stars that have an Earth-size object orbiting them in the “goldilocks” or habitable zone, where it is warm enough for the surface to retain liquid water.
• Kepler is succeeded by NASA's Transiting Exoplanet Survey Satellite, or TESS, which was launched in April 2018. TESS is the new planet hunter for NASA.