Scientists have discovered the smallest planet ever to be found outside our solar system.
Kepler-10b is 1.4 times bigger and 4.6 times heavier than Earth, although it could not support life.
That's because daytime temperatures there are over 1,300C - that's hot enough to melt iron and hotter than molten lava!
It's 560 light-years away from Earth and has a solid and rocky surface, just like our own planet.
It was discovered using NASA's Kepler telescope.
The telescope spotted the planet orbiting a star, a bit like our sun, hundreds of light-years away.
They could tell how big it was by measuring how much of the star's light was blocked out every time the planet orbited it.