MNN Galleries

10 incredible images of the sun

the moon in front of the purple sun

Photo: NASA

3 of 11

STEREO sees lunar transit

The NASA spacecraft STEREO-B caught this transit of the moon across the sun in 2007. NASA's STEREO mission consists of two spacecrafts launched to study [skipwords]solar[/skipwords] storms. [skipwords]Solar[/skipwords] storms are responsible for the magnificent beauty of aurora borealis on Earth, but they can also cause satellite failures, power blackouts and pipeline explosions. As experts note, [skipwords]solar[/skipwords] storms occur when an eruption on the surface of the sun sends radiation or electrically charged particles toward Earth. They can release the equivalent energy of 1 billion hydrogen bombs.