Eli5: how can astronomers know the age of a fast radio burst from space?

Question

Eli5: how can astronomers know the age of a fast radio burst from space?

In: Planetary Science

Answer 1

If you can identify the galaxy it’s from, you can use redshift: As the universe expands, all radiation shifts to longer wavelength. Elements like hydrogen absorb radiation at very specific wavelengths, if you see this pattern but it’s shifted then you know how much the universe expanded since the light was emitted. You can convert that to a distance estimate.