Astro 120: Fall 2008
Fall 2008 Review Sheet
Review Sheet 3
Exam 3 is December 16 at 4:30pm
The final exam is partly comprehensive - about half of the exam will
cover material since Exam 2 half from the first two parts of the course.
Be sure review the eariler material as well as that on
this sheet...
Part III:
Impacts, the Sun, Solar System History, and Life in the Universe
Astrology and Pseudoscience
- Fundamental ideas of astrology.
- Requirement for new unknown force.
- Testing astrology in a fair and rigorous way.
- Results of in-class experimet with sun-sign astrology.
- Results of more stringent experiments.
- Themes of pseudoscience; examples and how to tell
pseudoscience from objective science.
Impacts!
- impact record of the Moon compared with the inner planets
- terrestrial impacts.
- the impact hazard scale: small impacts are more frequent
- crater size related to impactor size (crater 10x larger than
impactor).
- effects of large impacts on life on Earth
- extinction of the dinosaurs: evidence of an impact causing it
- other sample impacts: Arizona meteor crater, Tunguska,
Comet SL9 and Jupiter.
The Sun
- Observed parameters of the Sun: temperature, size, luminosity.
- The solar photosphere, chromosphere and corona.
- Granulation, sunspots, prominences, flares.
- Sunspots, magnetic fields and the 22 year sunspot cycle.
- Energy generation in the Sun via nuclear fusion.
Formation of the solar system
- Collapse of the sun and solar system out of a molecular cloud.
- Gravitational collapse
- formation of a disk.
- Formation of planets in the solar nebula via
- condensation
- planetessimal formation
- accretion
- Temperature distribution in the solar nebula
- The'frost line' and formation of icy vs. rocky planets
- Time scale for planet formation was short (<<100 million years)
compared with the age of the solar system.
Other Solar Systems
- Observational challenge of finding planets around other stars
- Planet detection methods based on 'wobbling' of stars under gravitational
influence of surrounding planets.
- The radial velocity technique as the most prolific.
- Discoveries over the past 15 years of > 320 planetary systems
- the 'Hot Jupiter' issue
- Questions arising from these discoveries (i.e. is our solar system typical?)
- Searching for other Earth-like planets
Life in the Universe
- The probability of life on other planets - assumptions and guesses.
- Drake's estimator of the probability of finding a technological
civilization in the galaxy.
- Astronomical, biological, and sociologicaly factors.
- The habitable zone - liquid water and the development of life.
- Likely values for each factor in the Drake Equation.
- Which terms in the Drake "equation" are more certain, which are not.
- The Search for Extra-Terrestrial Intellegence (SETI).
- Methods used by SETI in the search for artificial signals from space.
- Why radio waves are a good way of transmitting signals across the
Galaxy?
- Current searches and results.
- Future prospects