How do we know How Old the Milky Way is?
For some reason, I never realized how old the Milky Way is. I'm so used to thinking in terms of the age of our Solar System.
2023-03-16 23:00:00 - Dr. Becky
00:00 | Introduction
00:58 | The GAIA telescope surveying 1 billion stars
01:28 | Parallax & proper motion
02:23 | What the spectrum of a star tell us
03:46 | GAIA 3D map of the Milky Way
04:23 | How we know how long stars live (the Hertzpsrung Russel diagram)
06:12 | Stars formed earlier are made of different ratio of elements
07:07 | Fitting model spectra to get ages
07:47 | Other methods: GYROCHRONOLOGY
08:36 | Other methods: PHOTOMETRY
09:17 | The oldest star known and its uncertain age estimate HD140283 (no it's not older than the Universe)
10:03 | Let's do this with a big sample of sub-giant stars (Xiang & Rix 2022)
12:14 | Deriving the age of the Milky Way (Xiang & Rix 2022)
12:52 | Brilliant
13:26 | Bloopers