Would gravity appear locally Newtonian on a neutron star?

  • 4 Replies
  • 1843 Views

0 Members and 1 Guest are viewing this topic.

*

Offline myself

  • Jr. Member
  • **
  • 12
    • View Profile
If you were picnicking on a (neutral, non-rotating) neutron star and an apple fell on your head, would it appear to have fallen in accordance with an inverse-square law?  Your view of distant objects would be distorted, of course, but that is a cumulative effect.  "You" and "apple," of course refer to single points rather than extended bodies. 

*

Offline Soul Surfer

  • Neilep Level Member
  • ******
  • 3345
  • keep banging the rocks together
    • View Profile
    • ian kimber's web workspace
Would gravity appear locally Newtonian on a neutron star?
« Reply #1 on: 04/05/2011 19:57:17 »
Yes but the acceleration of falling objects is so great that they pretty soon reach relativistic speeds.  You have to remember that the size of a neutron star is only around 2-3 time that of a black hole of the same mass and their escape velocity is over 1/3 of the speed of light.
Learn, create, test and tell
evolution rules in all things
God says so!

*

Offline imatfaal

  • Neilep Level Member
  • ******
  • 2787
  • rouge moderator
    • View Profile
Would gravity appear locally Newtonian on a neutron star?
« Reply #2 on: 05/05/2011 11:36:05 »
And (thinking aloud here) the gravitational potential changes so rapidly that time dilation effects might screw up attempts to make accurate measurements; not sure how/if this matters.
Thereís no sense in being precise when you donít even know what youíre talking about.  John Von Neumann

At the surface, we may appear as intellects, helpful people, friendly staff or protectors of the interwebs. Deep down inside, we're all trolls. CaptainPanic @ sf.n

*

Offline Soul Surfer

  • Neilep Level Member
  • ******
  • 3345
  • keep banging the rocks together
    • View Profile
    • ian kimber's web workspace
Would gravity appear locally Newtonian on a neutron star?
« Reply #3 on: 06/05/2011 08:38:47 »
You have to remember that all time dilation effects are only relevant to outside observers.  wherever you are as long as you are not too large a thing time always appears to flow perfectly normally. Now our questioner realised this when he described his objects as points.  the stronger the field gradient the smaller any object must be before it suffers from time distortion across itself.   Now that leads to some interesting trains of thought.....
Learn, create, test and tell
evolution rules in all things
God says so!

*

Offline imatfaal

  • Neilep Level Member
  • ******
  • 2787
  • rouge moderator
    • View Profile
Would gravity appear locally Newtonian on a neutron star?
« Reply #4 on: 06/05/2011 11:26:36 »
My mind had wandered to a falling observer and a watching observer - why I cannot say.  A building the size of that monstrosity in Dubai would have some rather interesting problems in both construction and setting a single time for the building
Thereís no sense in being precise when you donít even know what youíre talking about.  John Von Neumann

At the surface, we may appear as intellects, helpful people, friendly staff or protectors of the interwebs. Deep down inside, we're all trolls. CaptainPanic @ sf.n