Space review

How do we measure distance in space? Astronomical Units = 150,000,000 kilometers.  Our Earth is one AU from the sun

The first four planets are the rocky planets (mercury, venus, earth, mars) (mostly made of rock and metal) What is a planet? 1. must be round 2. must orbit the sun 3. must have cleared its orbital path  Pluto does not do number 3 so it is a dwarf planet The last 4 planets are the gaseous planets ( Jupiter, saturn, uranus, neptune) Mostly made of gas and liquid. 

satellites All planets except for Mercury and Venus have natural satellites (Moons)  Other celestial bodies:  asteroids =rocky bodies Meteoroid = smaller asteroids  Comets ice and rock.  They can orbit 

The moon The moon is about 1/4th the size of Earth's diameter. There are lots of craters, large round pits created from meteoroids Maria. Hardened rock formed from huge lava flows that occurred millions of years ago.  Highlands. Light colored features, high areas or mountains. (most of the moons surface is made up of this)  Temperature: hot during day cold at night  Does not have an atmosphere  How was the moon formed? A planet could have crashed into Earth sending a chunk off which turned into the moon

Mercury 1st planet No atmosphere Not much larger than the moon Lots of plains and craters

Venus Hottest planet (460 C) More than 10,000 volcanoes "What happens if you land on Venus? The atmosphere of Venus is very hot and thick. You would not survive a visit to the surface of the planet - you couldn't breathe the air, you would be crushed by the enormous weight of the atmosphere, and you would burn up in surface temperatures high enough to melt lead" -NASA

mars "the red planet" 4th planet from sun Air is 95% carbon, you could walk around but would need a space suit  Mars has water in the form of two frozen ice caps Mars is full of ancient streams and lakes

Jupiter  Largest planet, 2.5 times the mass of all other planets combined The great red spot: a storm larger than Earth

Saturn Second largest planet All gas giants have rings but Saturn's are the best. Made of ice and rock.  Saturn's largest moon Titan is larger than Mercury and only moon with an atmosphere 

Uranus Looks blue green due to traces of methane in atmosphere Tilts on a different axis of rotation 

Neptune 8th planet from the sun Blue color comes from atmosphere Had a giant storm like Jupiter but it has not disappeared. 

What else is in our solar system? Asteroid belt (between mars and Jupiter)  Kuiper Belt beyond Neptune Oort Cloud