A Window Into Time

Today Kepler-452b is receiving 10 percent more energy from its parent star than the Earth is from the Sun. If Kepler-452b had the same mass as Earth it would be on the verge of experiencing the runaway greenhouse effect and the loss of its water inventory. However, since it is 60 percent bigger than Earth, it is likely to be approximately five Earth masses, which provides additional protection from the runaway greenhouse effect for another 500 million years. Kepler-452b has spent six billion years in the habitable zone of its star; longer than Earth.


NASA Ames/J. Jenkins