Objects in the Solar System

Comets Composed of dust and rock particles mixed with frozen water, methane, and ammonia Halley’s comet appears every 76 years; last seen in 1986 Many times referred to as “dirty snowballs”

Parts of a Comet Nucleus – mass of frozen ice and rock Coma – bright cloud of vaporized gases and dust around the nucleus Dust tail – tail of dust from the solar winds pushing on the gas in the coma (points away from the Sun) Ion tail – tail of ions formed from the vaporization of particles

Asteroids Asteroids – rocky and metallic objects that orbit the Sun but are too small to be considered planets. They are known as minor planets Asteroid Belt is located between Mars and Jupiter

Meteoroid Pieces of rock left over from comets that are floating in space. Beginning of the cycle Baby stage

Meteors (Shooting or Falling Stars) Meteoroids that enter Earth’s atmosphere and start burning turns into a meteor Usually burn up before striking the ground Lots of meteors that burn at one time are called a “meteor shower” Teenage stage

Meteorite (Hits Right here on Earth) A meteor that doesn’t burn up and hits the surface of Earth or any other object becomes a meteorite Craters are left on the surface after the impact Adult stage

Dr. Dre D = MeteoroiD R = MeteoR E = MeteoritE

Stars A large, spherical mass of gas that gives off light and other types of radiation Constellations – observed patterns of stars in the night sky (Orion, Ursa Major) 88 constellations Color of a star indicates its temperature - Hot = Blue-White - Middle = Yellow - Cool = Orange or Red

Classifying Stars About 90% of all stars are main sequence stars White dwarfs – hot but not bright Giants – bright but not hot; also called red giants Larger ones are called supergiants

Evolution of Stars The life of a star depends on its mass All stars begin as a large cloud of gas and dust called a nebula High mass star→ main sequence→ red supergiant→ supernova →black hole or neutron star Low mass star → main sequence → red giant → white dwarf

Galaxies A large group of stars, gas, and dust held together by gravity We live in the Milky Way galaxy

Types of Galaxies 1. Spiral – have spiral arms that wind outward from center Ex. Milky Way galaxy

Types of Galaxies 2. Elliptical – shaped like a large, 3-D ellipse Many are football shaped, but others are round

Types of Galaxies 3. Irregular – those that don’t fit in the other categories

The Sun Center of the solar system and closest star to the Earth Light from the sun reaches Earth in about 8 minutes

Sun’s Layers Core – center of the sun; ball of gas that produces energy by fusing hydrogen into helium Radiation Zone – layer on the outside of the core Convection Zone – layer outside the radiation zone where gases circulate in giant swirls Atmosphere – outer layer of the sun

The Sun’s Atmosphere Photosphere – lowest layer of sun’s atmosphere; where light is given off Corona – largest layer of the sun’s atmosphere; extends millions of kilometers into space

Surface Features of the Sun Sunspots – areas that appear dark because they are cooler

Surface Features of the Sun Prominences – huge, arching columns of gas

Surface Features of the Sun Flares – violent eruption of bright gases shooting outward at high speeds near a sunspot

Surface Features of the Sun CME – coronal mass ejection; large amounts of electrically charged gas are ejected suddenly from the suns corona They help produce the auroras that cause the northern lights