This just blows my mind:
The fastest thing in the universe has come to a complete stop for a record-breaking minute. At full pelt, light would travel about 18 million kilometres in that time – that's more than 20 round trips to the moon.
"One minute is extremely, extremely long," says Thomas Krauss at the University of St Andrews, UK. "This is indeed a major milestone." ...
While light normally travels at just under 300 million metres per second in a vacuum, physicists managed to slow it down to just 17 metres per second in 1999 and then halt it completely two years later, though only for a fraction of a second. Earlier this year, researchers kept it still for 16 seconds using cold atoms.
Isn't that just incredible? Stopping light at all, let alone for a whole minute? And they don't think they've reached the limit yet, either.
I remember reading science fiction about this concept, though even then they just slowed light, rather than stopping it completely (admittedly, for much longer periods of time). But it's not just fiction, now. It's real.
OK, OK, light gets slowed down in a prism (as in the photo above), too. Indeed, I think it slows down when moving through any medium - even air - as the light-speed limit is when light moves through a vacuum. Still, this is pretty neat stuff, don't you think?