Skip to main content
Notice removed Reward existing answer by CommunityBot
Bounty Ended with no winning answer by CommunityBot
Tweeted twitter.com/StackPhysics/status/1038532790873206784
Notice added Reward existing answer by user4552
Bounty Started worth 300 reputation by CommunityBot
edited tags
Link
Qmechanic
  • 213.1k
  • 48
  • 590
  • 2.3k
Bumped by Community user
Bumped by Community user
added 327 characters in body
Source Link
Drake Marquis
  • 1.5k
  • 11
  • 22

One property of spatial infinity is that all spacelike geodesics end at it. Since spacelike geodesics can have different directions, I do not understand why spatial infinity is a point. It looks more like a 2 sphere instead of a point.


I will provide more information. Let us pick a point other than the spatial infinity in the conformal diagram. Usually, people draw the conformal diagram in a plane or represent it on the surface of a cylinder. So this point on a plane represents a 2 sphere. But spatial infinity is literally a point. Why?

One property of spatial infinity is that all spacelike geodesics end at it. Since spacelike geodesics can have different directions, I do not understand why spatial infinity is a point. It looks more like a 2 sphere instead of a point.

One property of spatial infinity is that all spacelike geodesics end at it. Since spacelike geodesics can have different directions, I do not understand why spatial infinity is a point. It looks more like a 2 sphere instead of a point.


I will provide more information. Let us pick a point other than the spatial infinity in the conformal diagram. Usually, people draw the conformal diagram in a plane or represent it on the surface of a cylinder. So this point on a plane represents a 2 sphere. But spatial infinity is literally a point. Why?

Post Reopened by John Rennie general-relativity
Post Closed as "Duplicate" by John Rennie general-relativity
Source Link
Drake Marquis
  • 1.5k
  • 11
  • 22

Why is spatial conformal infinity a point

One property of spatial infinity is that all spacelike geodesics end at it. Since spacelike geodesics can have different directions, I do not understand why spatial infinity is a point. It looks more like a 2 sphere instead of a point.