This is the Earth twin scientists have been searching for over the past 20 years. And it's called Kepler 452b.
Some scientists believe we're most likely to find life outside of Earth if we look beyond our solar system. Life, they think, could be present on a planet like Earth, but there are no such planets in our solar system, so we have to look farther.
Planets beyond our solar system do exist; they're called exoplanets. The first exoplanet was discovered in 1995. But despite identifying thousands of exoplanets over the last 20 years, scientists hadn't found a planet that's similar to Earth because there are a lot of boxes to check, including the type of star it orbits, the distance it is from that star, and the size of the exoplanet.
Now, they have one: Kepler 452b, which will forever be remembered as the first "second Earth," or what NASA refers to as "Earth 2.0," ever discovered:
Here's what we know so far about this Earth 2.0:
- It's 60% larger than Earth.
- It's most likely rocky, meaning it has a solid surface as opposed to nothing but a gaseous atmosphere, like Jupiter.
- It's about 1,400 light-years from Earth.
- It orbits its star every 385 days, very similar to Earth's orbital length.
- The planet and star it's orbiting are about 6 billion years old — 1.5 billion years older than our sun.
Although NASA does not know if there is life on Kepler 452b, Jon Jenkins, the Kepler data analysis lead at NASA's Ames Research Center, said during the announcement:
"It's simply awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star, which is longer than the age of the Earth," Jenkins said. "That's considerable time and opportunity for life to arise somewhere on the surface ... should all the necessary ingredients and conditions for life on this planet [exist]."
NASA used a planet-hunting space telescope, called Kepler, to find Kepler 452b. And scientists are more excited than ever about this new planet's potential.
"This is about the closest [to our Earth], so far," said John Grunsfeld, NASA's associate administrator for Science Mission Directorate in Washington. He added that this is just the beginning of exciting Earth-like planetary discoveries from Kepler.
In addition to the discovery of Kepler 452b, the scientists announced 11 more newly found Earth-sized planets. Here they are in a diagram. Kepler 452b is the only one orbiting a G star, which is the same type as our sun:
Right now, Earth 2.0 is receiving about 10% more energy than Earth does.
In another 1.5 billion years Earth will receive 10% more sun than it does now, which means that Kepler 452b is a look at what Earth could become.
Jeff Coughlin, the Kepler research scientist at SETI Institute, cautioned that 11 of these new planets are only candidates for exoplanets at the moment. They need to be further observed by other telescopes before scientists give official confirmation.
"There are some scenarios that can trick us," Coughlin said. "We need ground-based observations to really confirm that these are actual planets."
But at least one planet has been confirmed: Kepler 452b. This new discovery suggests that our home planet isn't alone in the Milky Way galaxy.
"We can say that near earth-sized planets in the habitable zone around G stars are common throughout our galaxy," Jenkins said.