Objects will actually keep moving forever unless there are other other forces to stop them. For example, if you jump right now, Gravity will pull you back to the Earth. The only time an object will keep on moving forever is in a perfect vacuum. I hope this was helpful...
-- If a moving object speeds up, slows, down, or changes its direction, then that has to be because there's some force on it.
-- If there's no force on an object, then it keeps moving forever, at a constant speed in a straight line.
-- We can never see that happening on Earth, because around here, there's always some force on a moving object ... like gravity, friction, and air resistance. In order for it to actually happen, it pretty much has to be happening in outer space.
Examples:
-- The Earth keeps moving around the sun, and TV satellites keep moving around the Earth, without slowing down.
-- Even the International Space Station, orbiting about 270 miles above the earth's surface, is <u>almost</u> outside all of the atmosphere, but not quite. There's still a tiny bit of air out there, slowing it down and 'decaying' its orbit. About once a month, they have to give it a short burst of rocket fire, to boost it back up to the altitude where it's supposed to be.
