Upload
luke-boone
View
218
Download
0
Tags:
Embed Size (px)
Citation preview
Chapter 3Solar System
Section 4Asteroids, Comets and
MeteoroidsNotes 3-6
Asteroids
Largest of the small bodies in the solar system
Fragments of rock that orbit the sun
Orbits are ellipses Ceres is found in the asteroid
belt but is now called a dwarf planet. About 1,000 km in diameter
Asteroids Asteroid Belt
Region between Mars and Jupiter Most asteroids can be found there Begins around 100 million km beyond
Mars’ orbit and continues for 150 million km toward Jupiter
Classified according to composition Carbon: gives a dark appearance Iron and nickel: have a metallic look Silicate minerals: most are this; look like
earth rocks
Asteroids
Believed that these are the remains of planetesimals that didn’t not form a planet Mostly because of Jupiter’s strong
gravitational force Trojan Asteroids: are also called
earth-grazers Orbit the sun but are not in the
asteroid belt Found around Jupiter Occasionally they do collide with
Earth
Comets
Comet: Body of rock, dust, methane,
ammonia and ice Nucleus: made of rock, metals and
ice Around 1km to 100 km in diameter
Orbit the sun in long ellipses Cloud of gas and dust is called the
coma Nucleus and coma form the head of the
comet Bright appearance is from light
reflecting off of it
Comets
Tail: Made of gas and dust that streams
from the head Form by solar wind and sunlight
pushing gas and dust away from the head
Tail always points away from the sun
Some tails can be more than 80 million km long
Comets
Oort cloud: Where most comets come from Named after the Dutch astronomer
Jan H. Oort Spherical cloud of dust and ice that
contains nuclei of comets Cloud surrounds the solar system
Starts at 1 ly from the sun Ends half way to the nearest star
From the beginning of the solar system; leftovers
Comets
Long-period comets: Have periods of several thousand or
million years Short period comets:
Have periods of up to 100 years Halley’s comet
Appears every 76 years Will appear again in 2062
Halley’s Comet
Meteoroids
Meteoroids: Smaller bits of rock or metal Most are less than 1 mm in
diameter From passing comets
Large pieces are from collisions with other meteoroids
Most burn up before they hit the ground
Shooting star (meteor) caused by friction of atmosphere
Fireball: vaporizes quickly
Meteoroids
Meteor shower: large amounts of meteoroids that come into the atmosphere at once Happen at the same time every year Earth passes through leftovers of
comets About 1 million kg of matter falls to
earth each day Meteorite: hits the ground;
makes it through the atmosphere Meteor Crater (Arizona) caused by a
large meteorite that hit
Meteoroids
Three types: Stony: like rocks on earth
Carbon substances Iron: have a metallic appearance Stony-iron: contain both types
Very rare
Can provide information about composition of the solar nebula
Iron Meteorite
Stony Meteorite
Dwarf Planets
Pluto
Pluto
Dwarf planet Discovered in 1930 by Clyde
Tombaugh, in Flagstaff, Arizona Diameter of 2,390 km
Smallest planet in the solar system Rotation rate = 6 days Orbital period = 250 years
Pluto
Has an elongated ellipse orbit Is sometimes inside Neptune’s orbit
Made of frozen methane, rock and ice
Average temp = -236 °C Has methane ice caps Has methane atmosphere
When it isn’t frozen
Pluto
Has one main moon = Charon Discovered in 1978 Appear to be a double planet system
Because they orbit so closely Found as an accident
Has two smaller moons orbiting it Nix and Hydra Between 50 – 60 km in diameter
Ceres
Has enough mass that its gravity causes it to be shaped like a sphere
Terrestrial – rocky Planet because
Orbits the sun Is round Not a moon
More Dwarf Planets
Makemake Third largest and
second brightest dwarf planet
Three quarters the size of Pluto
310 year orbital period
Made of methane, ethane and nitrogen ices
Eris Largest dwarf
planet in solar system – 27 % more massive than Pluto
Discovered in 2003 100 times farther
from Sun than Earth
Moon called Dysonmia
Orbits once every 16 days