What elements make up the vast majority of all stellar mass?
hydrogen and helium
100
What shape is the orbit of a planet around the sun?
Ellipse
100
What unit of distance is used to measure the size of the universe?
light years
100
Why does the moon glow at night?
reflects light from the sun
200
Why do smaller planetary bodies have little to no atmosphere?
they don't have enough gravity to hold onto their atmosphere
200
When a star's size is stable the force of gravity pulling the mass of a star inwards is balanced by the force of ______________ pushing it outwards
Thermal pressure
200
A 'day' is caused by a planet's rate of ______________
rotation
200
What evidence supports the theory of an expanding universe?
Red shift data (Hubble's Law)
200
What does apparent brightness of a star measure/describe?
how bright it appears from earth, as opposed to absolute brightness, which is calculated using brightness and distance.
300
What gases are gas giants made of, primarily?
hydrogen and helium
300
Large, cool stars that are very bright are known as ______________
red giants
300
The farther a planet it from the sun the longer its period of ________________
revolution
300
According to Hubble's law, the farther away a galaxy the _______________ it is receding.
faster
300
How are the sun, moon and earth oriented during a lunar eclipse?
The earth is between the sun and moon and casts a shadow on the surface of the moon.
400
Which planet in the solar system has the longest 'year'?
Neptune
400
Once a star has exhausted all available fuel it collapses inwards, creating a small, hot, dense body called a ______________ that gives off residual heat and light until it cools completely
White dwarf
400
According to Kepler's second law of planetary motion, when do planets move the fastest in their orbits?
when they're closest to the sun
400
Where do black holes come from?
The remains of the largest stars
400
What are the 'Maria' on the moon?
flat, lava covered plains
500
From what did our solar system form?
planetary nebula, remains of nearby supernova
500
What are two factors that can influence a star's color?
temperature and composition
500
What two forces balance each other to keep objects in orbit?
gravity and inertia
500
Approximately how old do proponents of the Big Bang theory estimate the universe to be?
13.7 billion years old
500
Why are ancient craters still visible on the surface of the moon?
Not atmosphere to create weather/erosion. Geologically inactive, due to solidified mantle.