Question | Answer |
What is a light year? | the distance that light travels in one year |
How is the distance of a star calculated? | by light years |
What is a galaxy? | a large group of stars, dust and gas |
How many stars does the largest galaxies contain? | trillions |
What is the size of most stars? | most are much larger than Earth |
Are all stars the same distance from Earth? | stars may appear to be similar distances away but their distances vary greatly |
Who began classifying galaxies in the 1920's? | Edwin Hubble |
What was Edwin Hubble's occupation? | astronomer |
What is a spiral galaxy? | a galaxy that has a bulge at the center and spiral arms |
What are the spiral arms in a spiral galaxy made up of? | gas, dust and new stars |
What is an elliptical galaxy? | a massive blob of stars that have very bright centers and very little dust and gas |
What do elliptical galaxies mostly contain? | old stars |
How many of all galaxies are elliptical galaxies? | about one-third |
What are irregular galaxies? | galaxies that don't fit into any other class |
Where are many irregular galaxies located? | close to large spiral galaxies |
In what type of galaxy is the Milky Way located? | a spiral galaxy |
What keeps astronomers from having a good view of our galaxy? | gas, dust and stars |
What are galaxies composed of? | billions of stars and some planetary systems |
What is a nebula? | large clouds of gas and dust that can be found in galaxies |
What forms in some regions of nebula? | new stars |
What are 3 characteristics found in some types of nebula? | they glow; absorb light and hide stars; reflect starlight |
What type of galaxy usually contain nebula? | spiral galaxy |
What type of galaxy contains very few nebula? | elliptical galaxy |
What are gobular clusters? | groups of older stars that look like a ball |
How many stars make up a gobular cluster? | up to 1 million stars |
What are open clusters? | groups of closely grouped stars |
Where are open clusters usually located? | along the spiral disk of a galaxy |
How many stars make up an open cluster? | a few thousand stars |
What does newly formed open clusters have? | many bright blue stars |
Why is looking through a telescope like looking back in time? | it takes time for light to travel through space |
What are some of the most distant objects that scientists study called? | quasars |
What are quasars? | star-light sources of light that are among the most powerful energy sources in the universe |
What does some scientists believe quasars may have caused in the cores of young galaxies? | black holes |
How can galaxies form new galaxies? | they can collide with one another |
What is the closest spiral galaxy to the Milky Way? | Andromeda |
At what speed are the Milky Way and Andromeda moving toward each other? | 500,000 km/h |
How many years will it take for the Milky Way and Andromeda to collide? | 5 billion years |