Everything Kids' Astronomy Book Read Online Free PDF

night. Many stargazers have found comets with nothing more than a pair of binoculars! If you just want to look at one that someone else has discovered,ask your family to let you know when a comet is scheduled to appear again. They can help you keep track of them and the other interesting events by reading astronomy magazines or checking http://skychart.skytonight.com/observing/skychart/skychart.asp on the Internet. The first time you visit this site you may need an adult to help you type in your location and time zone. (If you would rather use another site, that would be fine too.)
    Confusing Comets
    This astronomer is searching for a special comet, but there seem to be a lot of choices! Which is the one he wants? Use the clues to find out!
    The correct comet...
    ...must have 4 tails
    ...must have the tails on
    the left side
    ...must be round
    ...must be smooth
    FUN FACT
    Touched by the Sun
    Comets are called sun grazers because they come so near to the sun as they go behind it before they start back out into the solar system.
    Out of This World
    Imagine that you could take a ride on Halley’s comet. You know that it circles around the sun, but where would you be going on the return trip? You would have to travel billions of miles from the sun, past Neptune, to the source of most of the short-period comets. You might think your destination would be Saturn’s rings that are shaped like a plate and filled with thousands of icy snowballs known as Kuiper’s Belt Objects. Many astronomers wonder if icy Pluto and many of the moons orbiting the gas planets came from here. Have you ever wondered why the comets started their journey? A planet’s gravity may have tugged on them if they got too close or the comet could have been struck by debris passing through space. Your trip wouldn’t stop here if you were riding a long-period comet. They take hundreds, some of them millions, of years to orbit the sun so you could travel trillions of miles to the edge of the solar system! You’d be traveling to the Oort cloud, which encircles the solar system completely. Its comets can come from any part of the sky, not just from one direction like shorter-period comets do. You won’t see the Oort cloud on the Solar System Viewer on the Internet, because no one has really seen it, even with a telescope—astronomers just know it’s there! Be sure to check out the other orbiting objects in space. Even though the solar system is really big, some of these things look like they come pretty close to each other! Do you think as the universe expands or contracts that it will effect the orbits or courses of all these objects?
    WORDS to KNOW
    OORT CLOUD: There is thought to be a type of cloud that encircles our solar system, known as an Oort cloud. This cloud is believed to be the birthplace of some of the icy comets that can be found traveling through our solar system.

Chapter 8
Starry, Starry, Night

    T he first astronomers probably spent more time writing down what they saw than they did looking at the stars. Because they passed this information on to others, it was easier for the new stargazers to look for their own discoveries. Today’s astronomers continue to learn more about the creation and destruction of stars. Visiting a planetarium is like taking a guided tour of the universe that may make you want to learn more about the stars, the constellations, and all the interesting things that are happening in astronomy today.
    Just for Fun
    Indoor Night Sky
    To make an indoor sky, take a large piece of black plastic and draw the night sky on it with a silver paint pen. Use a pencil tip to make a hole for each star in the plastic so your stars will shine from the light outside. Tape the sky over the open end of a large appliance box. You will need a door in the box to get inside.
    Diamonds in the Sky
    When it starts to get dark each night, which are the first stars you see? The brightest ones, of course! Over 2,000