Jim Al-Khalili tells Adam Rutherford about the speed limit of our universe.
now playing
Series 8
Why nothing travels faster than light
The Baffled Bat
How do bats echolocate? And why don't they get confused by neighbouring signals?
The Dreadful Vegetable
Why don't children like vegetables?
The Cosmic Speed Limit
Can anything travel faster than the speed of light? Drs Rutherford and Fry investigate.
The Curious Face Off
Are machines better than humans at identifying faces?
Goldfinger's Moon Laser
Could we shoot a laser to the moon?