Earth in Space
Gravity and Motion
Characteristics and Lives of Stars
Star Systems and Galaxies
The Expanding Universe
100
The path earth follows.
What is orbit?
100
The tendency of an object to resist a change in motion.
What is inertia?
100
Imaginary patterns of stars.
What are constellations?
100
Star systems that have two stars.
What is a binary star?
100
Matter that does not give off electromagnetic radiation.
What is dark matter?
200
The imaginary line that passes through Earth's center and the North and South poles.
What is Earth's axis?
200
An object at rest will stay at rest and an object in motion will stay in motion.
What is Newton's first law of motion?
200
A star's brightness as seen from Earth.
What is a star's apparent brightness?
200
A system in which one star periodically blocks light from another.
What is an eclipsing binary?
200
Dark energy.
What is causing the expansion of the universe to accelerate?
300
When the sun is farthest North or South of the equator.
What is solstice?
300
The force that attracts all objects towards each other.
What is gravity.
300
The brightness a star would have if it were at a standard distance from the Earth.
What is absolute brightness?
300
These have a loose, disorganized appearance and contain no more than a few thousand stars.
What is an open cluster?
300
In the outer parts of the disks, gas and dust form small asteroid-like and comet-like bodies.
What is a planetesimal?
400
When the noon sun is directly overhead the equator. (It happens twice a year.)
What is equinox?
400
The law that states every object in the universe attracts every other object.
What is the law of universal gravitation?
400
The distance light travels in one year. (9.5 million million kilometers.)
What is a light-year?
400
These are large and densely packed with several older stars, some may contain more than a million stars.
What is a globular cluster?
400
A large cloud of gas and dust, such as the one that formed our solar system.
What is a solar nebula?
500
The two major motions of Earth as it travels through space.
What are rotations and revolutions.
500
Gravity and Inertia
What keeps the Earth in orbit around the sun and he moon in orbit around the Earth?
500
The apparent change in position of an object when you look at it from different places.
What is a parallax?
500
The main types of galaxies.
What are elliptical galaxies, spiral galaxies, and irregular galaxies?
500
The electromagnetic radiation left over from the big bang.
What is cosmic background radiation?
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