This lecture was to be about the Earth's atmosphere, its composition and
structure, the greenhouse effect, and the primordial atmosphere, but
about 2 seconds into the lecture, unbeknownst to me, the battery
compartment on my digital voice recorder came open in my pocket. At the
end of lecture, I took it out of my pocket to turn it off and the
battery didn't ... Show More
Oct 2009
Lecture 13: What is Life?
How do we define life? This lecture reviews the six basic criteria for living systems described by biologists: order, reproduction, growth and development, energy utilization, reaction to environment, and evolution that characterize life. The last third of the lecture is an admit ... Show More
46m 16s
<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
