Astronomy test study guide
The Astronomy unit test will be on Tuesday, December 11, 2012 for Ms. Whalen’s class.
One theory that scientists believe is that the universe was
created with a “Big Bang”. There are
other theories about how the universe was created.
We live in the Milky
Way galaxy. Milky Way galaxy is a spiral
galaxy. Other types of galaxies are barred,
elliptical, and irregular.
Gravity is the
force that holds our universe together. Gravity keeps our planets in their oval
orbits around the sun. The amount of mass something has determines how much
pull its gravity has: The heavier the planet/star/moon, the stronger the pull
of gravity.
There are other things that orbit around our sun such as asteroids and comets. A comet is a ball of ice, dust and gas.
As it gets closer to the sun it speeds up and begins to melt. As it melts, the
solar winds of the sun create a “tail” on the comet. When we see a comet, the
light is seen for days or a week at a time. A meteor is space dust. As this dust enters our atmosphere the
friction creates a spark that we might call a “shooting star”. The spark only
last a few seconds. There are two times of year when meteor showers happen:
August and November. An asteroid is a
large chunk of rocky material in space.
There is a large collection of asteroids orbiting the sun between the Jupiter
and Mars called the asteroid belt.