Kepler-452b – Earth’s cousin

Hunt for exoplanets oficially started in 1992 with confirmation of first planets orbiting a pulsar. In 1995 we found first exoplanet orbiting a main sequence star. Biggest news recently was the discovery of Kepler-452b named by some “Earth 2.0”. How big of discovery is it? Can we “look” into its atmosphere from a distance of 1400 light years?
Fraser Cain (publisher at, co-host of Astronomy Cast)

This is our best candidate for a twin of Earth, but we’re not quite there yet. Kepler-452b has 5 times the mass of Earth and twice the surface gravity. You would have a very difficult time surviving on the surface for any length of time. But it does orbit a sunlike star and it’s in the habitable zone. We’re so close, but I definitely wouldn’t call this Earth 2.0 yet. I’d like to see a world with a similar mass and surface gravity to Earth. Seeing a planet 1,400 light years will be really tough, so it’s going to be a long time before we can get any confirmation of life on this world.

Nancy Atkinson (Senior Editor for Universe Today, Host of the NASA Lunar Science Institute podcast & a NASA/JPL Solar System Ambassador)

We’ve been looking for another Earth-like planet for decades, and Kepler 452b is the closest we’ve found so far, so this is big news! It also means there are likely other candidates in the Kepler data – as well as others that Kepler is unable to find — that would be even more like Earth and perhaps not quite so far away. The one ‘bummer’ about the discovery is that Kepler-452b is 1,400 light-years away, so even with our fastest spaceship (something like New Horizons) it would take about 26 million years to reach it.

You’ve probably read the stats on this planet: it’s about 60% bigger than Earth, circling a sunlike star in its habitable zone, meaning it could hold liquid water. Astronomers suspect the planet is rocky and it likely has a thick atmosphere.

So, if you try to imagine, what it would be like to visit or live on this planet, all we honestly have now is speculation, since it’s too far away and we don’t have the technology to actually “look” at the planet. Astronomers also suspect that the star this planet orbits is older and is increasing in its energy output. This might be causing the planet to heat up and lose any water it might have, so if it is habitable now, it might not be for long. The artist’s concept picture that the astronomers collaborated on for this planet doesn’t make it look like a very hospitable planet!

Andrew Rader (SpaceX engineer, MIT PhD, author)

Based on previous Kepler finds, we suspected that there were many Earthlike planets out there – and think there are many more than the one, maybe as many as 6 billion in the Milky Way alone. So to some extent, the discovery wasn’t unexpected. However, it’s still always incredibly satisfying to actually follow through and identify what looks like the most Earthlike planet to date. So I’d say very exciting!

Unfortunately at that distance we can’t directly get much conclusive information on the planet’s atmosphere or composition. However, more precise and far-reaching sensors may allow us in the not too distant future to measure the composition of the atmosphere, and thereby learn a lot about the planet’s history, environment, and potentially life. Even more exciting discoveries await us.

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