# [Physics] Why Can We Observe Space Curvature / Warping At All

curvaturegeneral-relativityspacewarp-drives

I don't understand why we are able to see and measure curvature / warping of space at all.

Space as I understand it determines distances between objects, so if space were "compressed" or warped, shouldn't distances be compressed or warped the same way (like crumpling up a sheet of paper) ?

Then, however, our units of measure and frames of reference should be compressed likewise so that there should not be any visible changes to our cognition.

This would also rule out warp drives unless they form some wormhole in hyper-space (analogous to two points touching each other on the crumpled sheet of paper)…

What am I missing ?

I don't understand why we are able to see and measure curvature / warping of space at all.

The Earth's surface is curved and this can be observed via the vast number of pictures of the Earth from space that now exist.

However, the surface curvature can also be "seen" via measurements on the surface itself.

For example, if one were start at the North Pole and travel in a "straight line" (a great circle) to the equator, then move east along the equator for a quarter of the circumference, and then move North (always along a great circle), one would eventually reach the starting point at the North Pole.

But look, one would have formed a "triangle" with the interior angles adding up to 270 degrees! This is one way that intrinsic curvature is measured.

Simply put, intrinsic curvature is mathematically characterized by the Riemann Curvature Tensor and observed via geodesic deviation.