Up Next
Back to Show
PBS Space Time
How Do You Measure the Size of the Universe?
Season 1
Episode 3
The universe is HUGE. But, there is only so much of the universe we can ACTUALLY see, and if we wanted to measure that FINITE space, how would we do it? A gigantic ruler? One really long car ride? Or maybe it's something even more spectacular, something that involves not only the observable universe as it is NOW, but how it was when it was first BORN?
Support Provided By
14:20
Gigantic black holes existed in a cosmic eyeblink after the Big Bang. That should be impossible.
15:15
A decade later, a leading theory may finally explain Tabby’s Star, the galaxy’s weirdest star.
16:31
LIGO may have found an impossible black hole, hinting at primordial relics from the Big Bang.
17:40
DESI and DES studied dark energy. Together, what can they tell us?
16:28
Could sending a quantum twin across the galaxy make you both old and young at the same time?
17:39
It's possible that an event horizon is forming right behind and you won't know until its too late.
20:48
Are there no alien signals to find... or do we need to update how we search for them?
14:27
Physicists hope Planck stars can save us from black hole singularities and paradoxes.
17:41
Galaxies older than the universe? Webb's findings keep defying our best explanations.
16:16
Earth's core: solid or liquid? Yes — we know more about distant galaxies than our own interior.
14:42
Gödel found a time-travel solution in General Relativity, revealing spacetime can loop on itself.
18:46
Tardigrades can survive almost anything—even most of Mars. But one Martian chemical stops even them.