OBJECTS IN THE SKY: THE SOLAR SYSTEM Structure of the Universe

ƒ Earth is one of the eight planets in the Solar System ƒ Our sun is a star ƒ Stars cluster to form galaxies ƒ Our sun is one of over 300 billion stars in the Milky Way galaxy ƒ Milky Way is one of 100 billion galaxies in the visible Universe ƒ Most galaxies look like stars to us The Solar System

ƒ The Sun ƒ 8 Planets ƒ Moons of planets ƒ Other objects à Asteroids à Meteoroids à Comet

The Sun

ƒ The star at the center of the Solar System ƒ Diameter of ~109 times that of Earth ƒ Surface temperature: ~5505 C Mercury

ƒ Closest planet to the Sun ƒ Smallest planet in the Solar System

Venus

ƒ ƒ”–Šǯ•Dz•‹•–‡”’Žƒ‡–dz‘”Dz–™‹dzȂ similar size ƒ Hottest planet in the Solar System ƒ Has many volcanoes and craters ƒ Atmosphere is consisted of mostly carbon dioxide Earth

ƒ Surface: 70% water ƒ Atmosphere: 78% nitrogen, 21% oxygen ƒ Ozone layer blocks UV light ƒ Permits life Mars

ƒ Second smallest planet in the Solar System ƒ Š‡Dz‡†Žƒ‡–dzȂ iron oxide (gas) gives the surface a reddish appearance

Asteroid belt

ƒ Located roughly between the orbits of Mars and Jupiter ƒ Asteroids - small bodies in orbit around the Sun What it might look like if an asteroid hit Earth: Jupiter

ƒ Largest planet in the Solar System ƒ Has the most moons in the Solar System ƒ Gas giant, composed primarily of gas & liquid ƒ Giant Red Spot Ȃ storm Saturn

ƒ Second largest planet in the Solar System ƒ Pale yellow ƒ Visible rings of particles, mostly water ice Uranus

ƒ The coldest planetary atmosphere in the Solar System Neptune

ƒ Farthest planet from the Sun ƒ Active & visible weather patterns Comet

ƒ Icy small Solar System body ƒ When close enough to the Sun, displays a visible coma tail ƒ Tail is always pointed away from the Sun Meteoroid, Meteor, Meteorite?

ƒ Meteoroid: A small particle from an asteroid or comet orbiting the sun. ƒ Meteor: A meteoroid that is observed as it „—”•—’‹–Š‡ƒ”–Šǯ•ƒ–‘•’Š‡”‡ȋƒŽ•‘ called a shooting star). ƒ Meteorite: A meteoroid that survives its ’ƒ••ƒ‰‡–Š”‘—‰Šƒ”–Šǯ•ƒ–‘•’Š‡”‡ƒ† ‹’ƒ –•–Š‡ƒ”–Šǯ••—”ˆƒ ‡Ǥ Meteoroids might look like: Meteors might look like: Meteorites might look like: Evidence of a meteorite hitting Earth: (Meteor Crater, AZ)