Even if the environment is closed? What experiments could we propose to determine whether our entire universe is rotating or not?
This thread reminds me of questions my kids ask me, where they keep adding more and more details in the vain hopes of getting the answer they expected from the beginning.
Oh, and that I really want to marry Anne Neville.
>Even if the environment is closed? What experiments could we propose to determine whether our entire universe is rotating or not?
Well, the entire universe can’t rotate, because it has an infinite radius and relative velocities are always limited at c. That is, if a system rotates, all points in the system have instantaneous linear velocities relative to all other points, and masses moving with those points are forbidden to have relative velocities to other masses of c or greater.
One experiment you can do to see if the environment you’re in is rotating is to suspend a running gyroscope and see if the axis vector changes direction.
Another experiment is to fix two distant masses so that both are stationary relative to the environment, away from any gravitational fields, and then let go of them. If the system is rotating, they will move apart, because objects maintaining their distance in a rotating system are accelerating towards one another, and when you let go of your test masses you stop giving them the push needed to do this acceleration.
>Oh, and that I really want to marry Anne Neville.
Yes, me, too, I forgot this point.
blushes furiously
One possibility is to look for a Coriolis effect. Does an object in motion really keep going in a straight line, or does it deflect? Of course, there might be some practical problems with trying to observe this effect (you’d need an experiment on a scale not that much smaller than the whole universe), but it is conceptually simple.
I have heard that a rotating universe should produce some effects on the cosmic microwave background radiation that we don’t see. IANACosmologist, though, and I don’t know exactly what those are.
I love the SDMB and I don’t care if Chicago is moving or not. I’ve learned a lot of stuff from reading this thread; its a pity I won’t remember it tomorrow.
You still have other problems, though.
One of them is the observed phenomenon that, during meteor showers, you see more meteors between midnight and dawn than you do earlier in the night. There’s a simple explanation for this if the Earth is revolving around the Sun.
Don’t worry about it, Anne Neville. Without the flirting, the mods would have no chioce but to put this in GQ or GD.
You do have quite a gift for bringing these concepts within the grasp of a dunderhead such as myself, though.
more blushing
This is just what I needed today- I’ve had a bit of a rough week, and did some stupid stuff in the kitchen last night (not anything entertainingly stupid, just stupid, alas…) so I’ve been feeling pretty dumb.