•first read and then answer•
it was august 21, 2017. it was daytime. but for a short time in some places, it was as dark as night! what caused this? there was a total solar eclipse.

a solar eclipse happens when the moon passes between the sun and earth. the moon casts a shadow. it falls on earth. sometimes, the sun is partly blocked. but on august 21, there was a total solar eclipse. the moon almost fully blocked the sun.

scientists were excited. the sun is usually hard to study. it's too bright. but during solar eclipses, scientists can study the sun's corona. that's the outside layer of the sun's atmosphere. it's much hotter than the sun's surface. scientists want to learn why.

studying the corona could also scientists understand solar winds. these are streams of particles. they flow out from the sun's upper atmosphere. solar winds can change planets' atmospheres. scientists want to understand what happens. total solar eclipses could them do this.