They erupted for billions of years and make Earth's volcanoes look like molehills. Here's what we know and what we don't know about them.
This week, NASA has discovered great similarities between the Earth and Mars and Pluto. But when it comes to the potential for life, Mars is an increasingly hot favourite.
Now that we have discovered liquid water on the surface of Mars, what does this mean for the prospects of finding life there, past or present?
Everything in space is so far away, but probes bring us closer.
Astrophysicists found out after the January 2014 solar flare that their predictions of solar weather were not very accurate. Here's the fix (kind of).