Lecture 7
The Planets
(part 2, Jovian planets and the evolution of the solar system)

...the abstract art of the outer solar system (local screensaver)

Jovian Planets

Your book defines the "outer" or "Jovian" planets as: jupiter, saturn, uranus and neptune.

Comparison of Terrestrial and Jovian planets (Chaisson Table 6.2)

You must know the following 3 characteristics about these planets (see Table 6.1):

1. size (relative to Earth)
2. place/distance in solar system (specifically, the "order" from Sun, e.g., jupiter is the 5th planet from sun)
3. feature/fact. There are many we will over in lecture. The one you need to know will be defined in the class, and listed on the exam review hand-out.

Note: I've left Pluto off this list (as does your book by implication.) It is unlike both terrestrial and Jovian planets.

 

Media links

Most of the images we have are from the many spacecraft and robots sent to explore solar system. Nineplanets.org is a great resource.

 

Jupiter

• gas giant
• liquid-metalic-hydrogen interior (sci-fi and science)
• great red spot (movie1, movie2)
• 63 Moons! Four Galilean moons including Io (volcanos) and Europa (ice)

Saturn

• gas giant
• rings (Galileo, Optical telescope, Voyager 1, Voyager 2, Cassini)
• rings (how thick are they? what are they made of?)
• 56 Moons! Largest moon, Titan, visited recently by Cassini-Huygens probe (NASA and ESA). Huygens probe crash landed into Titan. Methane rain and atmosphere. More hydrocarbon liquid than Earth's oil and gas reserves

Uranus

• First "new" planet. Discovered with a telescope.
• rotates on its side
• structure

Neptune

• not discovered-- but "predicted"

 

All Jovian planets have rings

 

 

other "planets"

Pluto (smaller than moon)

Sedna, 2003 UB313 (or Eris) , etc.

But more on these in a bit...

other objects in the solar system

Asteroids

• 1000's objects mapped in the Asteroid belt
• tracked in time (ESA movie, Armagh Observatory movie)
• largest is Ceres

Comets

• Halley's comet and orbit
• "dirty snowball" model (Chaisson fig14.15 Halley taken from Giotto spacecraft)
• Deep Impact visits Comet Tempel 1

Meteors ... (Murchison Meteorite and others found to contain amino acids)

Stardust... (UHCL professor Michael Zolensky is Stardust's curator! collected comet dust and interstellar dust)

 

Kuiper belt (pic1, pic2)

Oort cloud (pic1, pic2)

 

What is a planet?

International Astronomical Union (IAU) demoted Pluto in 2006 :-(

Definition of Planet:

1. it orbits the Sun
2. it is massive enough that its own gravity has caused its shape to be approximately spherical
3. it has "cleared the neighborhood" around its orbit of other bodies

Pluto, Eris (Kuiper belt objects) and Ceres (asteroid) fail #3 and are classified as "dwarf planets"

New Horizons mission to study outer solar system, including Pluto and other KBO's or "trans-neptunian" objects

 

reading: see Chaisson Chap 14 (section 3).

 

Birth and Evolution of solar system

Formation of solar system (ESA movie1, Tufts movie2)

Solar Nebula theory (or "nebular theory") explains most features in terms of collapse from nebula.

Augmented by Condensation Theory which explains why the bodies are divided into Terrestrial and Jovian, etc. Planets can only form out of material capable of solidifying at each radius from hot center; e.g., heavy rock could withstand close distances, but not ice; conversely, cool light gas can condense at further distances from center.

 

 

Reading/Bibliography

Chaisson text:

• Chapter 6 (sections 4, 5, 7) Table 6.1
• Chapter 11 (sections 1, 3, 5, 6)
• Chapter 12 (sections 1, 4, 5)
• Chapter 13 (sections 1, 2, 6)
• Chapter 14 (all)

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

NASA's Planetary Photojournal

Cosmic Evolution from the Wright Center for Science Education at Tufts

European Space Agency (ESA)

Views of the Solar System

Sci-fi science blunders (including one on comet tails)

 

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/7/7.html