Intro to Astronomy Final
How is an astronomical unit defined?
The astronomical unit (AU) is the average distance from Earth to the sun.
What structures string together to form filaments?
Super-clusters—clusters of clusters
How big is the moon compared to Earth?
The moon's diameter is only one-fourth that of Earth.
About how many Earth's will fit between here and the Sun?
11,760 Earths between the Earth and the Sun.
How long does it take for light to cross the diameter of our Milky Way galaxy?
75,000 days
How far away is the moon from Earth when measured in Earth diameters?
On average the moon is 380,000 km (235,000 miles) from the Earth, a distance of about 110 times its own diameter.
How is a light-year defined?
One light-year (ly) is the distance that light travels in one year, roughly 1013 km or 63,000 AU.
Describe our location of our solar system within the Milky Way galaxy?
Our sun, the Earth, and all the other planets in our solar system reside within this Orion Arm. We're located close to the inner rim of this spiral arm, about halfway along its length.
How many galaxies like our own would it take, laid edge to edge, to reach the nearest large galaxy at 2.5 million light-years away?
The Andromeda Galaxy (closest galaxy to us) is 2.5 million light years away. So, it'd take 25 of our galaxy laid edge to edge to get to the Andromeda Galaxy.
If light takes 8 minutes to reach Earth from the Sun, how long does sunlight take to reach: 1. Mars 2. Jupiter 3. Venus
1. 12.6 minutes 2. about 43 minutes 3. 6 minutes
What is the diameter of Earth when measured in kilometers?
12,756 km (7926 mi).
What is the estimated distance across the Milky Way galaxy?
The Milky Way is about 100,000 light years across.
How much larger is the sun than the Earth?
The Sun is 864,400 miles (1,391,000 kilometers) across. This is about 109 times the diameter of Earth. The Sun weighs about 333,000 times as much as Earth.
Why can we not see the size and shape of the stars from Earth?
The stars are so far away, that when we look at a "star" in the sky, we are looking at it's light, and not the star itself.