The Universe

Front

What is a star?

Back

A star is a sphere of matter with a temperature and density great enough to cause a nuclear reaction at its center.

Front

What force holds a galaxy together?

Back

Gravity is the force that holds a galaxy together.

Front

What is a protostar?

Back

A protostar is a contracting mass of gas that represents an early stage in the formation of a star, before nucleosynthesis has begun.

Front

Which galaxy do we live in?

Back

We live in the Milky Way galaxy.

Front

What type of galaxy is the Milky Way?

Back

The Milky Way is a spiral galaxy.

Front

What is the main component of stars?

Back

The main component of stars is hydrogen, which undergoes nuclear fusion to produce helium and energy.

Front

What is a supernova?

Back

A supernova is a powerful and luminous explosion of a star that occurs at the end of its life cycle.

Front

What is a black hole?

Back

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

Front

What is dark energy?

Back

Dark energy is a mysterious force that is causing the acceleration of the universe's expansion.

Front

What is the difference between a spiral galaxy and an elliptical galaxy?

Back

A spiral galaxy has a flat, rotating disk with arms, while an elliptical galaxy is more rounded and lacks the distinct arms.