The discussion revolves around the concept of escape velocity and the gravitational pull of Earth on an object that has reached this velocity. Participants explore the implications of escape velocity, the effects of gravity at varying distances, and the behavior of objects once they leave Earth's gravitational influence.
Participants express differing views on the nature of escape velocity and its implications, particularly regarding how gravity affects an object over distance. There is no consensus on the best way to articulate these concepts, and the discussion remains unresolved.
Some statements made by participants rely on specific assumptions about motion and gravitational influence that may not be universally accepted or fully explored in the discussion.
It is inherent in the equations of motion. The object does slow down some but not down to zero. That's really the definition of escape velocity; giving an object sufficient velocity that gravity never quite overcomes it. Mathematically, when it gets to infinity it has zero velocity relative to the Earth (assuming it left with exactly the escape velocity), but of course in reality it will be more affected by celestial bodies other than the Earth WAY long before then (and the infinite "then" never actually occurs in reality)Zynoakib said:I know once the escape velocity is reached, the object will continuous to move away from the Earth. But the Earth's gravity can still act on the object no matter how far it goes, so what keeps the object from stopping or even returning back to Earth?
Thanks in advance!
phinds said:It is inherent in the equations of motion. The object does slow down some but not down to zero. That's really the definition of escape velocity; giving an object sufficient velocity that gravity never quite overcomes it. Mathematically, when it gets to infinity it has zero velocity relative to the Earth (assuming it left with exactly the escape velocity), but of course in reality it will be more affected by celestial bodies other than the Earth WAY long before then (and the infinite "then" never actually occurs in reality)
No, that's not a good way to say it. It will take forever for it to be slowed to zero.Zynoakib said:Just want to explain it in my own wording
Although the Earth's gravity can still attract the object to slow it down no matter how far it goes, it will take forever for the object to be slowed down just by a slight degree.
So, note that escape velocity is not a single/constant value. It decreases with distance. So an object that is launched exactly at escape velocity will always be slowing down, and will always be at the escape velocity of whatever distance it is at.phinds said:No, that's not a good way to say it. It will take forever for it to be slowed to zero.
Agreed for sure.russ_watters said:So, note that escape velocity is not a single/constant value. It decreases with distance. So an object that is launched exactly at escape velocity will always be slowing down, and will always be at the escape velocity of whatever distance it is at.