OTHER OBJECTS IN SPACE

ASTEROIDS Very small irregularly shaped, rocky bodies Orbit the Sun No atmosphere or internal heat Can hit a planet if it gets close enough to be pulled in by gravity

ASTEROID BELT Hundreds of thousands located there Mostly located between Mars and Jupiter Formed at same time as rest of solar system Jupiter’s massive gravity kept them apart

NEAR-EARTH ASTEROIDS Have orbits that cross Earth’s orbit Over 4,500 known to pass near Earths atmosphere Large asteroids in Earth’s past have caused mass extinction of organisms

METEOROIDS Debris left behind by comets and asteroids Large as boulders called asteroids Small as tiny grains of sand called interplanetary dust Sometimes cluster together with long tails

METEORS Forms a streak of light across the sky Often called shooting stars Light from burning meteor as it flies through Earth’s atmosphere Can come from comets, asteroids, or meteoroids

METEORITES Meteor that does not completely burn up in the atmosphere Provide clues about our solar system Some from asteroids or comets Some are from nearby bodies like Mars

METEORIODS, METEORS, AND METEORITES Meteoroid is dragged toward Earth by gravity It enters the atmosphere Friction heats the object As it flies in Earths atmosphere it leaves a trail of glowing gases it is now a meteor Most meteors never reach Earth Small core remains and hits Earth it is called a meteorite

COMETS Small icy objects that orbit the Sun Highly elliptical orbits Close to sun outer layers of ice melt Vaporized gas and dust form a “coma” Gases in coma and tail reflect light from sun Comets disappear when they move away from the sun Comet’s period is length of time from one visit close to Earth and the next

COMETS Where do they come from? Short period comets – 200 years or less come from the Kuiper belt – a region beyond Neptune Long period comets – thousands or millions of years come from a very distant region of the solar system –Oort cloud Comets may have brought water into the early Earth

DWARF PLANETS Objects that have not cleared their orbits of smaller objects Not enough gravity to clear objects Five dwarf planets in our solar system Ceres Pluto Makemake Haumea Eris