How do celestial bodies remain in orbit?

Question

I need this answer for homework.And I need it fast,Thanks!

Answer 1

If one body has an inertial momentum with respect to another body, and these bodies have enough gravity (gravity being an effect caused by mass), and a proper distance from each other, their combined momentum and gravity will cause them to revolve around a mutual center of gravity. Gravity and momentum/inertia allow the orbits to occur.

The interactions of gravity allow all objects with mass to create an orbit (as long as there is nothing else to interfere with the orbit).

Answer 2

because the gravitational attraction on the body balances its acceleration (so it can't fall in or fly away).

Isaac Newton figured this out.