Which term describes a massive collection of stars bound together by gravity?

Which term describes a massive collection of stars bound together by gravity?

• A. Universe
• B. Solar system
• C. Galaxy
• D. Nebula

Answer: (C)

A galaxy is a massive collection of stars bound together by gravity. It contains billions to trillions of stars, plus gas, dust, and dark matter, all held in a common gravitational field. The stars within a galaxy orbit around its center, and our Milky Way is a familiar example of a spiral galaxy. The other options aren’t a single bound collection of stars: the Universe includes all space and time, not just a bound system; a solar system is just one star with its orbiting planets; a nebula is a cloud of gas and dust, not a group of stars bound together.

A galaxy is a massive collection of stars bound together by gravity. It contains billions to trillions of stars, plus gas, dust, and dark matter, all held in a common gravitational field. The stars within a galaxy orbit around its center, and our Milky Way is a familiar example of a spiral galaxy.

The other options aren’t a single bound collection of stars: the Universe includes all space and time, not just a bound system; a solar system is just one star with its orbiting planets; a nebula is a cloud of gas and dust, not a group of stars bound together.