Back to Show
PBS Space Time
Why the Universe Needs Dark Energy
Season 2
Episode 27
We know the universe will continue to expand forever, so now we can begin to complete the first Friedmann equation, and determine the shape and geometry of our universe. At first glance, it would seem that the equation doesn’t quite add up, and that our universe is a hyperbolic plane. But when we add in the cosmological constant, the equation balances out, and we return to a flat universe.
Sign up now for inspiring and thought-provoking media delivered straight to your inbox.
Support Provided By

18:32
Dark matter has eluded us for many decades but we may be able to discover more now.

15:35
What do you get if you combine something that’s infinitely massive and negative infinitely massive?

13:39
What does an electron really look like?

16:35
Is there a limit to how much energy you can cram into, or pull out of one patch of space?

17:19
I’d like to invite you to an even higher level of nerdom!

11:43
Gravitational tsunamis exist and we’re on the verge of being able to detect them.

18:40
Will we ever become a Kardeshev Type-1 civilization and how can we get there?

14:05
New data is telling us that Neutron stars may make one of the most popular dark matter candidates.

15:14
Is Dark Energy Getting Weaker?

16:08
Here’s the story we like to tell about the beginning of the universe.

17:44
We’ve never seen a TDE in the Milky Way, but we’ve seen them in distant galaxies.

16:51
Let’s talk about quantum gravity experiments that can be done here on Earth!