How many intelligent, communicating civilizations live in our Galaxy?
We have no idea. One way to approach the question and come up with
quasi-quantitative estimates is the Drake Equation, first introduced by
radio astronomy Frank Drake in the 1960s. I will use the Drake equation
as an illustration of the issues related to the question of
extraterrestrial ... Show More
Nov 2009
Lecture 42: The Fermi Paradox
So, Where is Everybody? Interstellar colonization, in principle, is an exponential growth process that would fill the galaxy in a few million years even with a very modest star flight capability. This is a small fraction of the lifetime of the Milky Way Galaxy, so the Galaxy shou ... Show More
44m 58s
<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
