Vocabulary: Stars & Galaxies 24-25

Front

What is the Big Bang Theory?

Back

The scientific theory that states that the Universe began from one point and has been expanding and cooling ever since.

Front

What is an Astronomical Unit?

Back

The average distance from Earth to the sun, approximately 93 million miles or 150 million kilometers.

Front

What does the Hertzsprung-Russell Diagram represent?

Back

A graph that plots luminosity versus temperature of stars, helping to classify them.

Front

What is a Star?

Back

A large sphere of hydrogen gas held together by gravity that is hot enough for nuclear reactions to occur in its core.

Front

What is a Neutron Star?

Back

A dense core of neutrons that remains after a supernova, known for its extreme density.

Front

What is a Galaxy?

Back

A massive system that consists of stars, stellar remnants, interstellar gas, dust, and dark matter, bound together by gravity.

Front

What is Nuclear Fusion?

Back

The process by which two light atomic nuclei combine to form a heavier nucleus, releasing energy, and is the process that powers stars.

Front

What is Luminosity?

Back

The total amount of energy emitted by a star per unit of time, often measured in watts.

Front

What is Dark Matter?

Back

A form of matter that does not emit light or energy, making it invisible, but it exerts gravitational effects on visible matter.

Front

What is a Black Hole?

Back

A region of space where the gravitational pull is so strong that nothing, not even light, can escape from it.