The four large Galilean Moons of Jupiter seem unlikely places to look
for life; at first glance they should be cold, dead, icy worlds.
Instead we find tremendous geological diversity, and two big surprises:
volcanically-active Io, and icy Europa. Io is the most volcanically
active world in the Solar System, heated by tides from Jupiter. Europa
is even more ... Show More
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
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
<p>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.</p><br><p>L'importance de la masse</p><br><p>En évaluant, grâce à la ... Show More
