sky.
Imagine what your friends would say if you announced that a god lived on the moon and made the moon increase in size when it rose above the horizon and then made it shrink when it was high in the sky. Can you think of other myths you could tell each other? It does seem almost more like a story than something real, when you think about a universe born billions of years ago. Although the universe has been around for a long time, scientists think it may have formed very fast. Because the universe is constantly expanding, even the best experts can only guess how big the universe is or what shape it may be. Traveling millions and millions of light years to find the answers may take some time, but technology is getting us closer and closer each day. How big or what shape do you think the universe is?
Going Backwards?
Scientists call the start of the universe âThe Big Bang.â What do they call the theory that when the universe ends it will collapse in on itself? To learn this name, color in the letters that are not Z, Y, or X. Then read the dark letters from left to right, and top to bottom.
WORDS to KNOW
ASTRONOMY : Astronomy is the study of all things in space. The people who watch the skies for new stars or planets or changes in the ones that have already been discovered are called astronomers. Astronomy is a type of science.
The Big Picture
One way to see the world from a birdâs-eye view is to visit a Web site that shows your town and house from space. At Web sites such as www.terrafly.com , you can view your house from the sky! The picture starts out above your town like a bird or the pilot of a plane might see it. As the picture zooms in closer, you can see each house and the cars parked close by. To see this type of aerial map you can type in the words âaerial mapâ into your search box. Many of the sites offer you a chance to zoom in from space to your neighborhood or school. Another way to imagine how big the universe is would be to take a map of your country and mark where you live on the map with a piece of chalk. Although your town may seem large to you, on most maps that cover large areas it will just be a dot. In a map of the universe, our planet would also be a small dot.
How Big Is Big?
Astronomers figure that the universe has about 100 billion galaxies. If each galaxy has 100 billion stars, that adds up to a HUGE numberâ10 sextillion stars! Think about it this way: Ten thousand is a 10 followed by three zeroes, and ten million is a 10 followed by six zeroes. To find out how many zeroes are in 10 sextillion, break this number substitution (A=1, B=2, etc.) code.
Try This
Glow-in-the-Dark Galaxy
You can make your own spiral galaxy using a pinwheel and painting glow-in-the-dark or glitter paint on the top edges of each blade. Once it is dry, blow on the wheel to see how a spiral galaxy moves. If you used glow-in-the-dark paint, try it in a dark room. This is how our galaxy would look to someone out in space.
Countless Galaxies
Have you ever seen the Milky Way? This collection of stars can be seen all over the world; it looks like a ring of milk spilled across the sky. It is a small part of Earthâs own Milky Way Galaxy, which contains billions of stars, and you can see it with your own two eyes. If you could see it from another galaxy, it would look like a pinwheel that rotates every couple of hundred million years. Other galaxies may look like a racetrack or a splatter of paint. Did you know that if someone gave you a penny and then doubled that amount each day, you would soon have more money than you could ever spend? The same is true for our galaxies; there are just too many to be counted.
Sailing, Sailing
The Milky Way Galaxy and other galaxies in the universe display many of the bright stars that sailors in ancient times used like the map your family uses when you go on vacation. These early stargazers were the first people to practice astronomy; they were
Imagine what your friends would say if you announced that a god lived on the moon and made the moon increase in size when it rose above the horizon and then made it shrink when it was high in the sky. Can you think of other myths you could tell each other? It does seem almost more like a story than something real, when you think about a universe born billions of years ago. Although the universe has been around for a long time, scientists think it may have formed very fast. Because the universe is constantly expanding, even the best experts can only guess how big the universe is or what shape it may be. Traveling millions and millions of light years to find the answers may take some time, but technology is getting us closer and closer each day. How big or what shape do you think the universe is?
Going Backwards?
Scientists call the start of the universe âThe Big Bang.â What do they call the theory that when the universe ends it will collapse in on itself? To learn this name, color in the letters that are not Z, Y, or X. Then read the dark letters from left to right, and top to bottom.
WORDS to KNOW
ASTRONOMY : Astronomy is the study of all things in space. The people who watch the skies for new stars or planets or changes in the ones that have already been discovered are called astronomers. Astronomy is a type of science.
The Big Picture
One way to see the world from a birdâs-eye view is to visit a Web site that shows your town and house from space. At Web sites such as www.terrafly.com , you can view your house from the sky! The picture starts out above your town like a bird or the pilot of a plane might see it. As the picture zooms in closer, you can see each house and the cars parked close by. To see this type of aerial map you can type in the words âaerial mapâ into your search box. Many of the sites offer you a chance to zoom in from space to your neighborhood or school. Another way to imagine how big the universe is would be to take a map of your country and mark where you live on the map with a piece of chalk. Although your town may seem large to you, on most maps that cover large areas it will just be a dot. In a map of the universe, our planet would also be a small dot.
How Big Is Big?
Astronomers figure that the universe has about 100 billion galaxies. If each galaxy has 100 billion stars, that adds up to a HUGE numberâ10 sextillion stars! Think about it this way: Ten thousand is a 10 followed by three zeroes, and ten million is a 10 followed by six zeroes. To find out how many zeroes are in 10 sextillion, break this number substitution (A=1, B=2, etc.) code.
Try This
Glow-in-the-Dark Galaxy
You can make your own spiral galaxy using a pinwheel and painting glow-in-the-dark or glitter paint on the top edges of each blade. Once it is dry, blow on the wheel to see how a spiral galaxy moves. If you used glow-in-the-dark paint, try it in a dark room. This is how our galaxy would look to someone out in space.
Countless Galaxies
Have you ever seen the Milky Way? This collection of stars can be seen all over the world; it looks like a ring of milk spilled across the sky. It is a small part of Earthâs own Milky Way Galaxy, which contains billions of stars, and you can see it with your own two eyes. If you could see it from another galaxy, it would look like a pinwheel that rotates every couple of hundred million years. Other galaxies may look like a racetrack or a splatter of paint. Did you know that if someone gave you a penny and then doubled that amount each day, you would soon have more money than you could ever spend? The same is true for our galaxies; there are just too many to be counted.
Sailing, Sailing
The Milky Way Galaxy and other galaxies in the universe display many of the bright stars that sailors in ancient times used like the map your family uses when you go on vacation. These early stargazers were the first people to practice astronomy; they were
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