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, even
including great lakes of liquid methane and ethane at the poles.
Enceladus ... Show More
Nov 2009
Lecture 28: The Galilean Moons of Jupiter
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
activ ... Show More
44m 57s
Nov 2009
Lecture 27: Is There Life on Mars?
Is there life on Mars? We begin with a brief historical survey of the idea of inhabitable Mars, from Herschel to Lowell, and look at how the idea of Mars and Martians is deeply embedded in the popular culture. We then turn to spacecraft explorations of Mars, and how they have cha ... Show More
47m 4s
Oct 2009
Lecture 26: The Deserts of Mars
For many, the most likely place in the Solar System to search for life
beyond the Earth is Mars. This lecture describes the properties of
Mars, a desert world with a thin, dry, cold carbon dioxide atmosphere.
I will review evidence that has begun to point unequivocally to the
con ... Show More
47m 26s
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