In February, six planets will align in the night sky — Saturn, Mercury, Neptune, Venus, Uranus, Jupiter and Mars — and be mostly visible to the naked eye. We find out how to see and more about this ...

The exoplanet HD 20794d swoops in and out of its habitable zone every few hundred days, making for an extreme climate.

Shaped like a megaphone, the upcoming mission will map the entire sky in infrared light to answer big questions about the ...