Cosmology and astronomy: Cosmic background radiation 2

Cosmic Background Radiation 2 - Redshift of the Cosmic Background Radiation

Cosmology and astronomy

It's a great, big universe out there. In this section of Khan Academy, you'll learn about the brain-bending vastness of time and space. We go from plate tectonics here on Earth to entire galaxies and beyond.

Big bang and expansion of the universe

What does it mean for the universe to expand? Was the "big bang" an explosion of some sort or a rapid expansion of space-time (it was the latter)? If the universe was/is expanding, what is "outside" it? How do we know how far/old things are? This tutorial addresses some of the oldest questions known to man.

Topic: Science

Learn about all the sciences, from physics, chemistry and biology, to cosmology and astronomy, across hundreds of videos, articles and practice questions.