The universe, though, is an ancient place, so many civilisations could be very old indeed.

ECONOMIST: Is it time for a new approach to finding extraterrestrials?

Ancient rock art in Northumberland, thought to be up to 6, 000 years old, could disappear because of changing weather conditions, experts warn.

BBC: Climate change threat to Northumberland rock art

It might sound like something straight out of a Harry Potter movie, but a mysterious piece of rock salvaged from a 400-year-old wreck might turn out to be a legendary Viking "Sunstone" -- an ancient solar compass.

ENGADGET: Alt-week 3.9.13: Sunstones, knotted vortices and a zero-g robot

With research continuing into this strand of ancient history, it remains to be seen whether Pythagoras's theorem will come to bear the name of an old Babylonian scribe instead.

CNN: Pythagoras, a math genius? Not by Babylonian standards