The sun's atmosphere, or corona - the wispy part we see during solar eclipses - is hundreds of times hotter than the sun's visible surface, or photosphere. Why?
The moon will sweep in front of the sun June 10 to stage 2021's first solar eclipse. A bright ring, the sun's outer rim, will surround the moon at mid-eclipse.
There's a puzzling gap in exoplanets, orbiting distant stars. Where are the worlds between 1.5 and 2 times Earth's radius? Shrinking planets may be the answer.
With a global camera network, scientists track meteors of long-period comets - which take thousands of years to orbit once - to predict the next meteor rain.