system
Given the following post, respond as if you're commenting on Reddit:
human
Can you measure absolute velocity in space without a frame of reference?

Say you are in a patch of space a few light years across in all 3 dimensions and you have no frame of reference, say for some reason you cannot see any stars, its pitch black.

Could you measure your speed? 

Would it be of experimental interest (say, just to have a lab that is at rest relative to space itself) ?

(One method I thought about would be based on the speed of light being constant:

Imagine you are in a spaceship. You extend a detector array that includes a highly accurate atomic clock about a light second to your left. You then fire a laser at the thing and see if it hits. If you aim directly at the array and hit, then you are at rest, if not, you need to alter the angle of the laser beam to hit the detector. Based on the distance of the array, the angle on the laser beam and the runtime of the beam, you should be able to calculate your forward motion. You would of course need to have 3 arrays and 3 lasers to accurately dertermine your speed in 3 dimensions.)

Edit:
Thanks everybody!
gpt
No, you can't, because there's no such thing as absolute velocity. The speed of light being constant means it's constant in *all* reference frames; in general, there is no local experiment you can run to determine any sort of absolute speed.