Transcript A brief tour of the solar system

Suggested reading for next HW assignment:
Topic 5: Ken Nealson, Imre Friedmann
Topic 6: Peter Ward and Donald Brownlee
Bennett Ch. 9 &10
Goldsmith and Owen Ch.16-18
A brief tour of the solar system
Mercury
•Planet closest to the Sun
•Heavily cratered, no moons, no atmosphere, has
iron core
•0.38 the diameter of the Earth
•Surface temperature ranges from 90-700K
(mean=452 K)
•Relatively strong magnetic field (still 1% of
Earth’s)
MESSENGER
2004-2009
Venus
•Sometimes called Earth’s “Sister planet”
because similar in size.
•Atmosphere is primarily CO2 with small
amount of Nitrogen
•930 °F temperature
•Runaway Greenhouse effect
•Retrograde rotation
•80% of surface is basaltic rock (lava),
many volcanoes observed.
•Tectonics
•We have a 100m resolution radar map
of the surface.
•Craters but not many larger craters or
very small craters (WHY?)
Image from Venera 13
•Thin CO2 atmosphere
Mars
•-60 C average surface temp
•Very arid with no organic molecules
•Huge, dormant volcanoes
•Evidence of past water.
•Surface made mostly of volcanic rocks
•2 Moons: Phobos and Deimos
Map of Mars
Jupiter
•Largest planet in the solar systemmass=
318 Earths, volume=1200 Earths
•Brown Dwarf or “failed star”
•Mostly Hydrogen and Helium atmosphere
•Powerful magnetic field and gravitational
force
Jupiter’s Inner moons
Europa
Tidal heating
Saturn
•Mostly Hydrogen and Helium
•The rings are either left over
chunks of colliding moons or
else left over “construction
material” that never made it to
becoming a moon.
Cassini-Huygens
Titan
•Only moon in solar system to have a dense
atmosphere.
•There are ORGANIC molecules in the
atmosphere
•An atmosphere of mostly Nitrogen with
Methane
•Surface temp = -178 C
• Cryovolcanism?
Uranus and Neptune
Has methane-rich haze which strongly absorbs red & orange light, letting blue &
green light pass through.
•H, He, CH4 atmospheres
Uranus:
Lacks internal heat & so nearly featureless
Axis is tilted by 90º, giving extreme seasons.
Neptune:
Has internal heat & an active atmosphere
Pluto
•Really a trapped Kuiper-belt object
(smaller than our Moon)
•Kuiper-belt (50 AU out) consists of
icy planetesimals: Not all of the
outer solar-system material was
consumed when the gas giants
formed
•Has one moon: Charon
Comets
•Characterized by long period, heliocentric orbits
•Gases released include OH, CH, NH
•Nucleus of silicates and ice