PLANETS, MOONS, AND OTHER BODIES BY: ERIC

SUMMARY OF LESSON

VOCABULARY Asteroid: A small rocky object that orbits the sun Comet: A small orbiting body made of dust, ices and, frozen gases Galaxy: A huge system of gas, dust, and stars Meteor: A chunk of matter that enters Earth’s atmosphere and is heated by the friction of the air. Meteoroids: A bit of rock or metal that orbits the sun. Planets: A large body that rotates around a sun or star. Solar System: The sun and all the bodies that rotate around it.

THE BEGINNING OF THE SOLAR SYSTEM Scientist think that the solar system formed around 4.6 billion years ago. It might have formed by a hot spinning cloud of gas and dust. Over time gravity pulled the gas and dust to the center of the cloud, causing the cloud to collapse. The temperature was rising and building up more pressure. The farther places were colder and the matter from there made planets and moons. Planets close to the sun formed in rocky materiel. Planets farther from the sun formed much bigger and mostly gas. Along with the planets other parts formed like asteroids, comets, and meteoroids.

MOONS Moons are like satellites. They both orbit around planets and dwarf planets. Our planet Earth only has one moon which is about 4 times smaller than earth. It takes one month to complete the orbit around Earth. During the rotation the moon goes through phases where it looks like the shapes are changing or disappearing. Most of the information we know came fro Apollo mission 12, the astronauts took samples of the moon.

MOONS CONT. Other planets have moons. Theirs about 140 moons in all. Some have over 60 and some have none. All the moons are held by the planets gravitonic pull. Unlike Earth’s moon Saturn’s moon Titan and Neptune’s moon Triton have an atmosphere. Jupiter’s moon Europa has water under its icy caps.

ASTEROIDS There are millions of asteroids in the Solar System, most of which are found in the asteroid belt. This asteroid belt is between the rocky planets and the gas giants. Asteroids can be 100 km wide or just be 1. They also can be strange shapes as well. One theory is that Jupiter's strong gravitational pull kept the asteroids from becoming a planet. Another unlikely theory is that the chunks were from a planet collision.

COMETS AND METEORS Like Planets Comets also orbit the sun, but the travel with the head facing forward. When the comet get closer to the sun the ice vaporizes, releasing gas and dust making a glow called a coma. Energy from the sun causes the coma to grow millions of kilometers. Some of the comets path stretch out to Neptune, which only take 200 years to do a full orbit. Others stretch beyond Pluto and take millions of years. Meteors can be big in size like the one that killed the dinosaurs, or it can be one that didn’t even touch the ground They first started out as meteoroids from the asteroid belt.

BEYOND THE BOOK

MORE ABOUT THE SOLAR SYSTEM THE SUN IS 333,060 TIMES BIGGER THAN THE EARTH. ALSO IT HAS A SURFACE TEMPERATURE OF 5500 C. ONE DAY WE WOULD BE ABLE TO FIT INSIDE THE SUN WHEN IT BLOWS UP. THE MOON ALSO HAS EARTHQUAKES. USA CONSIDERED TO DROP A NUCLEAR BOMB ON THE MOON. SOME ASTEROIDS HAVE THEIR OWN MOON.

HALLEY’S COMET HALLEY'S COMET WAS DISCOVERED BY EDMOND HALLEY. HALLEY’S COMET IS VISIBLE IN YEARS. THE NEXT TIME WE WILL SEE IT IS IN THE PATH OF THE PLANET STRETCHES TO PLUTO AROUND WHICH IS 30 AU AWAY.

THE END