A decades-old rule about human friendship turns out to be built on such shaky math that it could just as easily be 2 or 520.

What can a rare disorder tell us about human behavior?

One in 60 adults Fiji lives with HIV but a recent emergency declaration may help address key issues such as syringe sharing

A Little Tooth - Your baby grows a tooth, then two,

Physicists have long struggled with their goal of making gravity a quantum force. A radical post-quantum approach might solve that problem – and clear up other cosmic mysteries, too

The descent of stable societies into ones of endemic violence rarely produces anything but new forms of tyranny and terror.

Social media has been a boon to autocratic regimes and their allied movements in democracies.

New research - it’s one of the largest studies of emotional intelligence to date

Former British Prime Minister Gordon Brown shares what it was like to run a country, the effect it had on his personal life and what life is like after being in

I joined the Green Party of England and Wales in 2014.

Cosmic radiation comes from space. Only a small amount reaches the Earth's surface, but exposure is greater for people flying at high altitudes.