Download THE SOLAR SYSTEM

SOLAR SYSTEMS
CHAPTER 21
definition
• Objects that revolve around a star
• Major members
– Planets
– Moons
• Minor members
– Dwarf planets
– Asteroids
– Comets
– meteoroids
What is a planet?
(as of Aug. 2006)
• The IAU said that the definition for a planet is now officially
known as "a celestial body that
• (a) is in orbit around a star
• (b) has sufficient mass for its self-gravity to overcome
rigid body forces so that it assumes a (nearly round)
shape and
• (c) has cleared the neighborhood around its orbit."
(not in a swarm of rocks)
Our solar system scoreboard
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Planets= 8
Moons= 167
Dwarf planets= 5
Asteroids= 536,000+
Comets= 3,062
Exosolarsystems
• Other solar systems
• 661 new solar systems confirmed!
• Over 3000 planets (exoplanets)
First discovered in 1995
Estimated over 50 BILLION
Earth like planets
(habitable zone)
• Maybe 2?
• Gliese D
– 6x more massive than earth “superearth”
– In Libra
– 20 lya
• HD 85512 b
– In Vela
– 26 lya
HOW DO ASTRONOMERS FIND
NEW PLANETS???????
Radial Velocity
• Planets are detected by
studying light shifts due
to star wobbles
• Uses Doppler Effect
– Red light moves AWAY
– Blue light moves
TOWARDS
Astrometry
• Measures star wobbles from geometry
Transit method
• Planet blocks star (eclipse)
• Light from star is lessen
• Kepler mission
Optical detection
• Block star’s light out using a chronograph
List of exoplanets
• http://exoplanet.eu/catalog/
Exoplanet missions
• Kepler- launched 2009
• Has found 77 planets so far
METHODS to find a new planet
• http://planetquest.jpl.nasa.gov/Planet_Finder
/planetfinder.html
Other research
• LBT (large binocular telescope)
• Keck telescopes (Hawaii)
• Spitzer Space Telescope
– Infrared telescope
OUR SOLAR SYSTEM
Our solar system
The planets drawn
to scale
INNER PLANETS
INNER PLANETS
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Terrestrial
Rocky
No rings
Smaller compared to Outer planets
MERCURY
• No atmosphere
• Temperatures fluctuate wildly
• MESSANGER is currently orbiting
Mercury- has completed 282
orbits (so far!)
Sept. 29, 2009
MESSANGER
Messenger 9/21/11
• Mapping surface of Mercury
MESSANGER IMAGE
Aug. 23. 2012
VENUS
• THICK atmosphere
– Hot!
– Crushing pressure
• Rotation is retrograde
– Sun rise in west; set in east
Pancake volcanoes
MARS
• Thin atm.
• Windy
• Surface similar to Earth
– Volcanoes
– Old river valleys- where’s the water?
– Best chance to find fossil (life?) in SS
Opportunity and Spirit
• http://marsrovers.jpl.nasa.gov/home/
CURIOSITY
landed Aug. 6, 2012
CURIOSITY
CONFIRMS WATER
ONCE FLOWED!!
Mars Moons
• Phobos
• Deimos
Jovian Planets
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Outer planets
Large
Many moons
all have rings
Made of gas
JUPITER
• Often captures
comets/asteroids
– Shoemaker/Levy
comet (1994)
Jupiter’s Ring system
Feb. 2007
Jupiter’s New Moons
• Jupiter now has
63
known moons
• 23 moons were
discovered in 2002-3 by
Earth-based telescopes
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter&Display=Moons
Saturn’s Rings
• Made of Water ice
and dust
• Sheppard moons
keep rings in place
Uranian Weirdness
A few of Uranus’s moons
MIRANDA
ARIEL
PUCK
OBERON
Neptune
• Very active weather
Triton-
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Liquid nitrogen volcanoes
Cantaloupe terrain
Underground oceans?
Alien life?
Planet ?
• 2003 UB313
• Renamed Eris (Xena)
What is a planet?
(as of Aug. 2006)
• The IAU said that the definition for a planet is now officially
known as "a celestial body that
• (a) is in orbit around a star
• (b) has sufficient mass for its self-gravity to overcome
rigid body forces so that it assumes a (nearly round)
shape and
• (c) has cleared the neighborhood around its orbit."
(not in a swarm of rocks)
Pluto
• Dwarf planet
Lowell Observatory
where Pluto was discovered
1939
Plutoids
• Dwarf planets beyond Neptune
• Established in 2008
Planets, dwarf planets, plutoids
How many moons does Pluto have?
We’re on the way…
• New Horizons
spacecraft was
launched in Jan. 2006
• Will arrive at Pluto July
2015