# Is spacetime curvature relative?
**URL:** https://boards.straightdope.com/t/is-spacetime-curvature-relative/161613
**Category:** Factual Questions
**Created:** [March 15, 2003, 4:47pm UTC](https://boards.straightdope.com/t/is-spacetime-curvature-relative/161613 "2003-03-15T16:47:47Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Sacroiliac](https://boards.straightdope.com/u/Sacroiliac)
#### Post date: [March 15, 2003, 4:47pm UTC](https://boards.straightdope.com/t/is-spacetime-curvature-relative/161613/1 "2003-03-15T16:47:47Z")
From what I have read spacetime curvature is equal to the mass/energy density plus 3 times the pressure. Now if you and I are the exact same location in spacetime but moving at different velocities we will measure different mass densities and pressures. Does this mean that gravity/curvature is velocity dependant and relative?
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 15, 2003, 5:39pm UTC](https://boards.straightdope.com/t/is-spacetime-curvature-relative/161613/2 "2003-03-15T17:39:46Z")
Every measurement is relative. Since there are only three basic units of measure; mass, time, and linear dimension; and all of these are affected by relativistic effects, we cannot say any measurement is absolute, including the curvature of spacetime.
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### Author:  [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)
#### Post date: [March 15, 2003, 5:53pm UTC](https://boards.straightdope.com/t/is-spacetime-curvature-relative/161613/3 "2003-03-15T17:53:48Z")
That’s not quite true, **Q.E.D.** While the distance (delta-d) and the time (delta-t) between two events are relative, delta-d[sup]2[/sup] - (c\*delta-t)[sup]2[/sup] is invariant. Also rest mass is sometime called invariant mass, because it does not depend upon the observer.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 15, 2003, 6:00pm UTC](https://boards.straightdope.com/t/is-spacetime-curvature-relative/161613/4 "2003-03-15T18:00:20Z")
Quite so, **DrMatrix**. I was focusing on the OPs question and forgot to include that bit of information. Though, I believe my answer to the original question was still correct, unless I’m overlooking something fundamental again.