Space junk includes old satellites, spent rocket stages, dust from solid rocket motors and even coolant from obsolete Russian nuclear-powered satellites. But just how much is up there?
The gold in a Nobel Prize medal is dense enough to make a big impression when you try to take it through an airport X-ray scanner. It's also very resistant to being dissolved—but that didn't stop one chemist who needed to hide two medals from the Nazis, as Dr Karl Kruszelnicki explains.
A condition called misophonia — where people adversely react to particular sounds, often with feelings of rage, terror, fear and panic — was first identified 20 years ago, but is only now starting to be better understood.
They can seal tight, suck, blow, whistle, hold and kiss. With hundreds of muscles and multiple layers of cells, the human lip serves a much greater role than we give them credit for.
5 min
About Great Moments In Science
From the publisher's feed
From the ground breaking and life saving to the wacky and implausible, Dr Karl Kruszelnicki reveals some of the best moments in science.