According to current scientific theories, dark matter and dark energy make up most of the universe. But we don't even know what they actually are.

China is bringing a huge new radio telescope on-line, and part of its stated purpose will be to search for alien life.

Belgian information activist Paul Otlet envisioned some of the possibilities of today’s Web more than a century before its existence.

Tambora's explosion was one of the largest volcanic events in recorded history.