NASA’s Breakthrough Discovery of the First Truly “Earth-Like” Planet

NASA has reported the finding of the first planet that is truly Earth-like. This discovery was made possible by the Kepler Space Telescope, which was launched in March 2009 and has been searching for planets for the last five years. 

“It is the first terrestrial planet in the habitable zone around a star very similar to the Sun,” said Douglas Caldwell, an astronomer at the SETI Institute in Mountain View, California, at the moment of the discovery.

It was a watershed event in the finding of Earth-like planets, and it would go down in history.

Kepler 452 is a Sun-like star that roams through the known universe 1,400 light-years from Earth. It has the same surface temperature and approximately the same energy output as our Sun. Finally, the Sun and Kepler 452 are both G-typee yellow dwarfs. This suggests that Kepler 452's habitability zone (the region around a star where liquid water may hypothetically exist) is virtually equal to the Sun's.

And, if that isn't enough, there is a planet that circles on a pretty much identical route to Earth's—it falls almost exactly in the same place in our own solar system that Earth does.

Because the star is so similar to our own, the duration of a year on the planet is nearly comparable to ours, and the quantity of energy received by the planet is startlingly close to what Earth receives. Kepler 452b is the given name of the planet. It has a 385-day orbit (amazingly close to our own 365-day year), and it gets just 10% more energy than the Earth. All of these requirements allow for human settlement (if only we could get there).

Notably, Earth and Kepler 452b aren't simply orbital twins; they're also twins in a variety of other ways.

Scientists are unable to precisely estimate the mass of Kepler-452b, but conclusions based on modeling imply that the planet is just five times as massive as Earth (nearly 60 percent larger). That clearly suggests that this is a rocky world similar to our own, which is a good thing (since we don't have the technology to survive on gas giants). Furthermore, while five times the mass may seem like a lot, astronomers predict that Kepler 452b has just twice the gravity of Earth. Again, this allows for habitability.

And that isn't all. Kepler 452 is around the same age as our sun. As a result, astronomers believe Kepler 452b is somewhat older than Earth. This suggests that the planet has been in the habitable zone of its star for around 6 billion years. This is more time than Earth has been in the sun's habitable zone and (obviously) more than enough time for complex life forms to emerge.

Kepler experts are completely taken aback by the discovery.

“On the 20th anniversary year of the discovery that proved other Suns host planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble the Earth and our Sun,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. 

“This exciting result brings us one step closer to finding an Earth 2.0.”

[h/t NASA][This is an updated version of the previous article with new information]