Why will an object in space continue moving foever?

[THP]

Why object in the space will continue moving foever if the object is in dynamic equilibrium?

 

[haruspex]

Why object in the space will continue moving foever if the object is in dynamic equilibrium?

Are you asking which of Newton's Laws implies this, or why Newton's Laws are true?

 

[THP]

I want to know why Newton's laws are true

 

[jbriggs444]

I want to know why Newton's laws are true

Scientific laws are ultimately based on experiment. Experiment agrees that Newton's first law holds good in all the situations where we have tested it.

One can drive a bit deeper. The law of conservation of momentum can be shown to follow from the principle that the laws of physics over here are the same as the laws of physics over there. Experiment agrees with that principle as well.

https://en.wikipedia.org/wiki/Noether's_theorem#Basic_illustrations_and_background

 

[David Lewis]

Why object in the space will continue moving forever if the object is in dynamic equilibrium?

If you are moving and the object is at rest, it's an identical situation, and you certainly wouldn't expect space object to start moving out of the blue for no reason.

 

[haruspex]

If you are moving and the object is at rest, it's an identical situation, and you certainly wouldn't expect space object to start moving out of the blue for no reason.

I don't think you can prove the correctness of Newton's law this way. You just shift the question.
As jbriggs wrote, the law was based on observation, while Noether's theorem shows how it follows if the laws of physics are the same everywhere, but there is no way to prove that either.

On Noether's theorems, I have always been intrigued by the pairing of concepts that arises in two contexts:

• Momentum and position.
• Angular momentum and angular position.
• Energy and time.

In each case, conservation of the first follows from the laws of physics being invariant under displacements in the second.
In each case the (dot) product of the pair has dimension of action. Indeed, the product relates to the Planck/Heisenberg uncertainty.