Main content
Trail: Light and Dark
Professor Jim Al-Khalili tells the story of how we worked out what light is, and how we used that knowledge to reveal the universe.
Duration:
This clip is from
More clips from Light and Dark
![]()
The first discovery—Dark
Duration: 02:04
![]()
Dark energy—Dark
Duration: 04:07
![]()
Galactic rotation—Dark
Duration: 01:55
![]()
The dark ages of the Universe—Dark
Duration: 01:33
