dr-becky 11 months ago
astrophysicist #Space and Time

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.

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

Dr Becky Smethurst
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