Lecture 9
Asteroids and comets; solar system formation
Wednesday July 16, 2008
Today we concluded our tour of the solar system with asteroids and comets,
then discussed the formation of the solar system. The powerpoint is on Angel.
We looked at these helpful videos about Hale-Bopp and solar system formation
and this youtube about Spitzer observations of
star-forming regions in the Orion nebula.
Concepts:
- Asteroids: Small chunks of rock, also can have water ice, organics. Asteroid belt is between Mars and Jupiter
- Comets: Dirty snowballs of ices and dust that evaporate as they go around sun, causing long tails
- Nebular theory: Solar system formed from collapse of nebular cloud into swirling disk, planets grew in stages
Vocabulary:
- Carbonaceous/silicate: Types of asteroids; C-type are darker, more water/organics, tend to be in outer belt
- Oort cloud: Very distant (~50,000 AU) shell of frozen bodies, source of long-period comets
- Meteroid: Small bit of rock, forms meteor (shooting star) in atmosphere (meteorite if gets to ground)
Activity:
Reviewed Homework #1 as preparation for midterm on 7/21.
Random link:
Excerpt from Northern News article titled "Scientists close to confirming water on Mars"
Trenches the arm has since dug revealed a white substance similar to that exposed by the spacecraft's thrusters. In pictures taken four days apart by the Phoenix, images show chunks of the white substance had vanished, strongly suggesting they were composed of ice that had sublimated to water vapor once exposed. Fisher said project leaders are "99.9%" sure it's ice, and expects to know early this week once a sample is analyzed by a mass spectrometer to determine its molecular weight. "If it is what we think it is," he said, "then that is going to provide the possibility one might find habitats for indigenous life forms on Mars. There looks to be a huge source of water there."
Updated July 16, 2008