Asteroids Orbits
Jupiter systematically pushes asteroids on certain orbits if they are in resonance
Keeps Debris mixed so it never could form another planet
Orbital Resonance
For every time N times one of them orbits the other orbits M (eg. 3:4 here).
So their gravitational pull gets repeatedly reinforces.
How close are asteroids together?
In reality: I M sized objects are on average 70 km apart
Near earth objects
We know of 10,000 near earth objects: orbits are in the same part of the solar system as us.
We know of 1500 potentially hazardous asteroids: orbits cross within 1 earth radius of the earths orbit. Could hit us one day!
The Joivian Planets (“gas giants”)
Internal structure
Rock/ice cores, of 10 earth masses, covered by hydrogen + helium (different amounts of H +he determines mass of planets)
“ices” = water (h20), ammonia (NH3), methane (CH4) internal Jupiter
Largest planet in the solar system (1/1000th mass of the sun, 300x mass of the earth)
Visted by the Voyagers 1+2 (1979), Cassini (2000, en route to Saturn), New Horizons (2007, en route to Pluto), Galileo (1995-2003)
Jupiter’s Red Spot
Giant Hurricane, at least 300 years old.
Jupiter’s Clouds
Cloud layers form of different compounds at different heights in the atmosphere. Colors we see depend on how deep we see (whether the upper layers are cloudy)
Saturn
1/3 the mass of Jupiter, but nearly the same diameter (density is less than water).
Gas giants are very “squishy” so extra mass = extra gravity =higher density.
Saturn’s Northern hemisphere
Probably due to fluid dynamic instabilities
Saturn’s rings
All the outer planets have rings, but Saturn’s are by far the most prominent
Extremely thin
Dust-meter-sized chunks of ice.
Rings
Would dissipate after millions of years if left on their own. Occur in all Jovian planets, so not just a coincidence of something that happened recently. Must be continually replenished.
Small “moonlets” get continually impacted by sand-sized particles, releasing new ring particles.
Uranus and Neptune (“ice giants”)
Blue color from methane clouds
Uranus is tipped completely on its side
Neptune’s “great dark spot” lasted 6 years.
Jovian Moons
Jovian planets have lots of moons
Like small planets, but colder (more ice than rock)
Many show recent or ongoing tectonic, volcanic activity despite small size.
Tidal heating
Composition
Comets
Icy porourus clumps tha usually orbit in the outer solar system- “Dirty Snowballs” – a few km diameter ranging up to 3000 km.
Two main resivoirs
Kupiter Belt
Oort “cloud”
Comets in the Inner Solar System
The ice evaporates! (technically subliminates)
Frozen gasses get ionized and pushed directly away from the sun by solar wind: ion tail cometary tails only stay for small amounts of time
Tails form about 1 AU away from the sun and tail points away from the Sun.
Dust tail is pushed by sunlight
Meteor Showers
Larger particles (unseen) don’t get pushed away by solar wind or light, they just stay along the comets orbit.
These small particles spread out along the comets orbit, leaving
Radiate from a point that depends on the direction the earth is moving and
They all radiate from one point
Meteors on a meteor shower appear to emanate from the same area of the sky because of earths – through space
1866 Leonid meteor shower (100,000 meteors an hour) formation of the solar system observations: terrestrial vs. Jovian planets flat plane with mostly circular objects most orbit and rotate in the same direction
Protosolar Nebula
The solar system formed from a collapsing very-slowly-spinning gas cloud
Collapses:
Turns gravitational potential energy into thermal energy. Heats up
Conserves angular movement, as it gets smaller. Spins up
Condensation
Components of the protosolar nebula condense (become solid) at different temperatures
Small pieces of whatever can locally condense planetesimals,
