Lecture 6
The Planets
(part 1, Earth and the Terrestrial Planets)

 

Overview

Nineplanets.org [sic, "eight"]

Overview

Properties of solar system objects Table 6.1

Earth: The Blue Marble

The Blue Marble

Lights (small, large, sunset) and Flights

 

A 3d interface to the Planet
(Google Earth... Google is not evil, but does give away what Dr. Faust had to pay a considerable sum for back in the 16th century)

Earth's Vital Stats

 

 

Magnetism

magnetosphere (Chaisson figs7.19 and 20 )

gallery of Auroras (animation, pbs/nova) or Northern Lights

 

Evolution of Earth's Crust

Earth's terrain is not static, but constantly evolving, eroding, re-forming due to heat constantly rising out from center of planet.

 

Volcanism (undersea vents and ring of fire)

Tectonics (continential drift movie)

 

Tsunami of 2004

 

Earth's Atmosphere

Atmospheric layers (Chaisson fig7.2)

Greenhouse effect (Chaisson fig7.5)

Global warming (Chaisson Discovery 7-1)

(Global dimming?)

Evolution of earth's atmosphere.
Two atmospheres historically. Proliferation of plant-life (and e.g., cyanobacteria) caused a transition from a rich carbon dioxide and poor oxygen atmosphere to our present atmosphere with rich oxygen and poor carbon dioxide.

 

Terrestrial Planets (and earth's moon)

Besides earth, the other terrestrial worlds defined by your book are the earth's moon, mercury, venus and mars.

 

Though sharing similar internal structure and evolutionary history there are differences. You must know the following 4 characteristics about earth's moon, mercury, venus and mars:

  1. size (diameter relative to Earth, Chaisson Table 6.1)
  2. place/distance in solar system (specifically, the "order" from Sun, e.g., venus is 2nd planet from sun, Chaisson Table 6.1)
  3. orbit
    • Moon: synchronous rotation (tidal forces)
    • Mercury: a day is twice the length of a year (!huh? Chaisson Fig8.13)
    • Venus: rotates retrograde
    • Mars: rotational parameters close to earth (roughly same 24hr day and 25degree equatorial tilt, giving roughly same daily and "season" variations as earth)
  4. atmosphere
    • Moon: very little (1.0E-15 pressure of earth)
    • Mercury: very little (1.0E-15 pressure of earth)
    • Venus: thick 96% CO2, sulfuric acid clouds (i.e., massive greenhouse effect, acid rain, 740K temperature)
    • Mars: ice caps at poles (water ice and dry-ice CO2) visible with telescope or ESA spacecraft. Massive dust storms... even dust devils. (atmospheric pressure 1/100th earth, mostly CO2)

Evidence for Life on Mars

Robotic rovers (Spirit and Opportunity) search planet for signs of life;

 

Scale Model of the Universe #2

Lab exercise: Build a scale model of the Solar System.

 

Earth ~ blue marble (1 cm diameter)

 

All scales are approximate; what is important here is to get a intuitive feel for the system.

Reading

Chaisson text:

The Nine Planets, A Multimedia Tour of the Solar System, by Bill Arnett

NASA's Planetary Photojournal

The Blue Marble

John Walker's Earth and Moon viewer

TerraServer online earth imagery

National Oceanic & Atmospheric Administration (NOAA)

USC study of long term changes in climate

The Astrobiology Institute has an online repository of microscope images from all sorts of organisms

If all this talk of evolution and billion year old worlds conflicts with your personal religous beliefs, you might look at the writings of Pierre Teilhard de Chardin (a Jesuit priest) who strived to harmonize his science and his religion. [ WIRED article]

 

Astronomy mnemonics, if you need help memorizing the order of the planets.

Classic:

"My Very Educated Mother Just Served Us Nine Pizzas"

Post-2006 after Pluto demotion:

"My Very Educated Mother Just Served Us... Nothing."

To include the Asteroids and Comet cloud (Oort cloud) one ASTR3131 student came up with this adaptation:

"My Very Educated Mother, Amazingly, Just Served Us Nine Pizzas. Cool!"

Document URL: http://www.uh.edu/~jclarage/astr3131/lectures/6/6.html