Up Next
Back to Show
PBS Space Time
How We Know The Earth Is Ancient
Season 6
Episode 11
In astronomy we talk about billions of years like it’s no big deal. But how can we be sure about timescales so far beyond the capacity for human intuition? Our discovery of what we now call deep time is very recent - as recent as our discovery of the true spatial vastness of our universe. And it came as scientists tried to measure the age of the Earth. What they found was shocking and humbling.
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.