Chapter 7: Space The final frontier

Our solar system was “born” about 5 billion years ago The solar system is made of the Sun, eight planets, natural satellites, comets and asteroids. The sun : a star at the center of the solar system. All the planets follow paths around the sun called orbits Orbits – the path all planets follow around the sun

Closest star to the earth Made of hydrogen and helium Temp C on outside 15,000,000 0 C in center Gives off enormous amounts of energy

“My very excited mother just served us nachoes” Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune

The planets close to the sun are solid These are : Mercury, Venus, Earth, Mars The planets farther out are gas giants made of hydrogen and helium. These are :Jupiter, Saturn, Uranus, Neptune Asteroid belt

Pg. 357

Terrestrial planetsGas planets Relative distance to sun (close/far) Relative size (big /small) Composition Density ( high density/ lo density) Rotational speed (Fast/Slow) Rings (rings/no rings) Moons (few or none/ many) Magnetic field (Weak-none/ strong

Mercury and Venus only ones without moons Jupiter has the most and largest moons Earth has one

Made of ice rocks and dust Found beyond Neptune’s orbit

Comets follow an oval orbit around the sun

When it gets close to sun ice sublimates and with dust that is released from the nucleus, forms the tail The tail always points away from the sun in the direction of the solar wind Passing the sun, lots of debris left by comet results in meteor shower or shooting stars

Meteoroids when they hit the earth cause minor disruptions Asteroids impacting earth have destroyed existing life forms  In Quebec –Manicouagan crater 100 km in diameter

Asteroid collision in Yucatan caused mass extinction of dinosaurs

Shooting stars (meteors) - debris from comets burn up in the thermosphere and mesosphere =tqOmAA0HlEM =tqOmAA0HlEM

Revolution of the Earth – The Earth revolves around the sun takes 365 days and causes the changing of seasons Rotation of the Earth – The Earth rotates on its own axis takes 24 hours and causes the cycle of day and night

The Earth turns on a tilted axis This rotation movement causes the cycle of day and night

1 rotation of the earth takes 24hours

It takes the Earth 365 (and a quarter) days to revolve around the sun (that’s why we have leap years) Because of the Earths tilt we are in different positions during the year. This is what divides the year into four seasons (spring, summer, fall, winter)

Caused by the solar wind. When the solar wind particles arrive near the Earth, they are diverted toward the poles. These particles stimulate the particles in our atmosphere which create the lights.

384,400 km from earth Does not give off light- it reflects the suns rays It takes 29.5 days for the moon to circle the earth It is responsible for the oceans tides

Result from the play of light from the sun by the different positions of the Sun, the Earth and the Moon Phases: 1. New moon 2. First quarter 3. Full moon 4. Last quarter 5. Back to new moon

When the Earth, the Moon and the Sun are perfectly aligned in space There are solar eclipses and lunar eclipses Solar EclipseLunar Eclipse

Solar eclipse – the moon is between the sun and the earth, casting a shadow on the earth

Lunar eclipse- earth is between the sun and the moon “blocking out the sunlight” - no reflection (moon is red) Happens twice a year