Today's Outline

Today’s outline

Review: Gas and Ice Giants 2

Asteroids Asteroid Belt Homework 4 due Saturday morning Jupiter’s Inﬂuence Meteors Test next Monday Meteorites Comets Tails Review: Gas and Ice Giants 2 End Meteor Showers Comet Origins Asteriods and Comets

I The asteriod belt

I Meteors and meteorites

I Comets

I Oort Cloud and Kuiper Belt Review: Gas and Ice Giants 2

Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Meteorites Comets Tails Review: Gas and Ice Giants 2 End Meteor Showers Comet Origins Review: Gas and Ice Giants 2

Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Asteriods and Comets Meteorites I The asteriod belt Comets Tails End I Meteors and meteorites Meteor Showers Comet Origins I Comets

I Oort Cloud and Kuiper Belt Asteroids

Review: Gas and Ice Giants 2

Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Meteorites Comets Tails End Meteor Showers Comet Origins

I Leftover building blocks (planetesimals) of the rocky planets.

I Formed inside the frost line and therefore made of rock and metal

I Wide range of sizes from rocks up to dwarf planet size

I Largest, Ceres, about 1/3 diameter of our Moon

Dwarf planet: Large enough to become spherical due to self-gravity Planet: Orbits by itself (possibly with a moon) around the sun Asteroid Belt

Review: Gas and Ice Giants 2 I Vast bulk of asteriods Asteroids Asteroid Belt between orbits of Mars Jupiter’s Inﬂuence Meteors and Jupiter Meteorites Comets I Some scattered other Tails End places in inner solar Meteor Showers system and along Comet Origins Jupiter’s orbit

I These belts have survived stably since the formation of the solar system But why didn’t these chunks form into another small rocky planet? Jupiter and the Asteroid Belt

Review: Gas and Jupiter is constantly gently Ice Giants 2

”stirring” the asteroid belt Asteroids through orbital resonances Asteroid Belt Jupiter’s Inﬂuence Meteors I Clears asteroids from some Meteorites orbital resonances Comets Tails Accumulates them at others End I Meteor Showers Comet Origins I This constant perturbation prevented asteroids from accumulating into a planet

I Also gradually decreased the mass in the belt over time

I Continues to cause collisions that can eject asteroids from the belt Meteors

Meteors: Shooting stars, formed mostly by small ”rocks” burning Review: Gas and up in the Earth’s atmosphere. (may be icy too) Ice Giants 2 Meteor refers to the observed phenomenon, not so much the rock, Asteroids Asteroid Belt a meteoroid. Jupiter’s Inﬂuence Meteors Meteorites Comets Tails End Meteor Showers Comet Origins Meteorites

Meteorites: Rocks large enough to Review: Gas and survive the fall through the atmosphere Ice Giants 2 and be recovered on Earth Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Origins: Meteorites Comets I ”Primitive meteorites” – formed Tails End by accumulation of rock and Meteor Showers metals in the forming solar system Comet Origins

I ”Processed meteorites” – pieces of larger bodies ejected by impacts

I from large asteroids I from the Moon and Mars Underwent diﬀerentiation (settling of heavy stuﬀ) Some primitive meteorites even contain pre-solar dust grains formed in supernovae and winds of other stars. Comets

Review: Gas and Ice Giants 2

Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Meteorites Comets Tails End Meteor Showers Comet Origins Comet Tails

Review: Gas and Ice Giants 2

Comet: Icy body being slowly stripped apart by solar Asteroids Asteroid Belt radiation Jupiter’s Inﬂuence Meteors Meteorites I Made of a mixture of Comets ice, rock, and metals Tails End I Originally formed in Meteor Showers Comet Origins outer solar system, past frost line

I Ionized gas from evaporated ice forms one tail

I Dust blown oﬀ by Has tail only when near the sun escaping gas forms Often on large, long-period orbits another tail Comet’s End

Review: Gas and Ice Giants 2

Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Meteorites Each time near the sun some of the Comets Tails comet is removed End Meteor Showers Comet Origins Eventually the comet will break up and become just dust

In general all sorts of pebble-size debris is following along the comet’s orbit from it being broken up Meteor Showers

Meteor showers: Earth moving through orbital path of a comet Review: Gas and and all the debris that it leaves behind. Ice Giants 2 Asteroids Asteroid Belt Jupiter’s Inﬂuence Meteors Meteorites Comets Tails End Meteor Showers Comet Origins

The direction of the streaks indicate the direction the earth is moving through the debris cloud. Comet Origins Originally created in outer solar Review: Gas and system (beyond snow line) Ice Giants 2

Many have been scattered by Asteroids interactions with planets Asteroid Belt Jupiter’s Inﬂuence Meteors Meteorites Now reside in orbits in: Comets Tails I Oort Cloud: Collection of End Meteor Showers comets with extremely large Comet Origins orbits at random orientations, scattered by planets

I Kuiper Belt: Orbits just a bit beyond Neptune, close to but not in plane of planets, formed here Can be sent into inner solar system due to interactions with planets or a passing star