Why do stars shine? How long do they shine? This lecture describes the
physics of stars on the main sequence, describes the mass-luminosity
relation of main sequence stars, introduces nuclear fusion power and the
nuclear fusion lifetimes of stars. From this we gain an important
insight into one of the criteria we might apply to the search for life
around ... Show More
Nov 2009
Lecture 31: The Properties of Stars
What are the observed properties of stars? This lecture is a quick
review of the basic observational properties of stars, introducing
luminosity, spectral classification, the luminosity-radius-temperature
relation, and the Hertzsprung-Russell (H-R) diagram. This sets up the
empir ... Show More
46m 37s
Nov 2009
Lecture 29: The Children of Saturn
Among the 61 known moons of Saturn, two stand out: Enceladus and Titan.
Giant Titan is the only moon in our Solar System with a substantial
atmosphere, composed of nitrogen and methane, dense enough to maintain a
weather cycle with methane analogous to the water cycle on Earth, e ... Show More
46m 10s
Mar 2022
Comment calculer l'âge d'une étoile ?
La durée de vie d'une étoile peut nous renseigner sur sa composition et sur l'existence éventuelle de la vie dans le cosmos. mais, en dehors du Soleil, il est assez difficile de déterminer l'âge d'une étoile.
L'importance de la masse
En évaluant, grâce à la radioactivité, l'âge d ... Show More
1m 58s