Astronomy Lecture Notes
November 14 2012h
- Venus mass + radius are similar to Earth but atmosphere is 96% CO2 and
temperatures = 470 K due to being closer to the Sun
o No liquid water.
- Study of Venus’ surface using radars volcanoes, larger craters, very few
rifts, no continental drift.
- Rotation = 243 days “backwards”
Chapter 8 – Jovian Planet (from Monday):
- Large masses + diameter small densities
- Composition mostly of Hydrogen and Helium from densities + spectral
patterns – cold enough that no element can escape.
Interiors of Jovian Planets:
- We cant go inside them, but we are beginning to use “seismology “for these
planets only indirect methods:
o Composition = hydrogen and helium
o Jovian planets all rotate rapidly causes planet to bulge at their
o No observed expansion or contractions.
Outward pressure = weight.
- Use a computer:
o Use the composition of Hydrogen and Helium
o Solve the equation: outward pressure = weight.
o Apply observed equation.
o Predict the bulge at the equator.
o If does not match the observed bulge adjust the interior by trial and
Repeat until predications matches observed bulge.
- Results for Jupiter:
o Atmosphere is made up of Hydrogen, Helium and H2 and other
molecules go to a depth of 10% 7000 km.
o “Oceans” compressed liquid H and He depth = another 10% = 7000
o Liquid metallic H (something we cannot create on Earth) – almost to
o Solid core of rock and metal = 10X MEarth
- Results of Saturn:
o Deeper atmosphere and oceans
o Smaller Hydrogen metallic but larger core.
- Results of Uranus and Neptune: