Does a gyroscope bend spacetime?

[nipoleon]

I've tried to find the answer to this but I can't
I know what we experience as gravity is the bending of space by the mass of the Earth. But, a gyroscope is able to defy the Earths bending of space.
Does a gyroscope on a small scale bend space perpendicular to the Earths bending and that's why it stays up? Once the gyroscope loses energy it's bending of space-time diminishes and it can't stay up anymore.

 

[Ibix]

I know what we experience as gravity is the bending of space by the mass of the Earth.

Spacetime, not space. You can't describe gravity solely by spatial curvature.

Does a gyroscope on a small scale bend space perpendicular to the Earths bending and that's why it stays up?

No. It stays upright due to the conservation of angular momentum, and has no noticeable effect on spacetime.

 

[Dale]

But, a gyroscope is able to defy the Earths bending of space.

No it is not. A gyroscope free-falls just as fast as anything else. It is also subject to tidal effects just like anything else.

 

[nipoleon]

Exactly what is the proper description of gravity?
What is the conservation of angular momentum?

 

[Dale]

Exactly what is the proper description of gravity?

GR is more accurate than Newtonian gravity, but for the purposes of a gyroscope Newtonian gravity is an adequate description of gravity.

What is the conservation of angular momentum?

Conservation of angular momentum says that $\tau= dL/dt$ where $L$ is the angular momentum of the system and $\tau$ is the net external torque on the system.

 

[phinds]

Exactly what is the proper description of gravity?

As ibix said, you don't need GR to analyse a gyroscope, just use Newtonian gravity.

What is the conservation of angular momentum?

Are you saying that you don't know what the definition of angular momentum is or you don't understand when and how it is conserved? Google is your friend.

EDIT: I see Dale beat me to it.

 

[Nugatory]

Exactly what is the proper description of gravity?

General relativity is the best theory of gravity that has been discovered so far. As @Ibix says, it is based on curvature of spacetime not space.

What is the conservation of angular momentum?

It's one of the basic laws of classical mechanics, along with conservation of energy and conservation of momentum. It will be explained in any first-year mechanics textbook, something like Kleppner and Kolenkow... and the Wikipedia article is ok.

 

[Ibix]

Exactly what is the proper description of gravity?

As I and others have said, curvature of spacetime, not space. If you want a rigorous answer, you need a textbook. Former PF Mentor Ben Crowell wrote a non-mathematical introduction, "Relativity for Poets", which is freely downloadable from his site, http://lightandmatter.com/poets/.

What is the conservation of angular momentum?

Loosely, things that spin will continue to do so and will resist attempts to change their axis of rotation. If you can find one of those fidget spinners that were all the rage (in my country at least) a year or so ago you can try it yourself - set it spinning in a horizontal plane and feel it resist if you try to turn it to spin in a vertical plane.

This effect is responsible for gyroscopes staying vertical or, if they are tilted, precessing rather than falling. It's a purely classical effect, understandable in Newtonian mechanics.

 

[CWatters]

Its worth noting that a gyroscope and its supporting tower weigh the same when the gyroscope is _apparently_ defying gravity as when its stationary. That because a gyroscope doesn't produce a force that counters gravity, it produces a torque.

 

[nipoleon]

I've always understood that mass and velocity are proportional.
An increase in velocity increases mass. Gravity is a function of mass.
Does not the velocity of the spinning wheel create an increase in its mass at the edge of the wheel?
If not then what is that?

 

[Dale]

I've always understood that mass and velocity are proportional.

No, that is not correct. I am not sure where you got that but it is not right.

If not then what is that?

I am not sure what “that” refers to here. Please clarify

 

[nipoleon]

You mean an object in motion does not increase in mass with respect to its velocity?
As an object travels faster and approaches the speed of light, does its mass not increase?
I'm sorry but that's what everybody says.
As a flywheel rotates faster, shouldn't its mass also increase at the outer edge?

 

[Dale]

You mean an object in motion does not increase in mass with respect to its velocity?
As an object travels faster and approaches the speed of light, does its mass not increase?
I'm sorry but that's what everybody says.

The concept that you are talking about is called “relativistic mass”. It is a deprecated concept that is no longer in use by the physics community as a whole. The only place where it is still used today is in pop-sci sources.

When you just say “mass” it refers to “invariant mass” which does not change with speed. Relativistic mass is a pretty useless concept (just another name for total energy) but if you insist on using it you need to explicitly specify that you are talking about relativistic mass, not mass.

However, even relativistic mass is not proportional to velocity as you stated above, not even close. The relationship is highly nonlinear. For the speeds of ordinary gyroscopes it is utterly negligible. Certainly not enough to have any measurable effect on anything with even the most sensitive modern equipment.

 

[A.T.]

Once the gyroscope loses energy it's bending of space-time diminishes and it can't stay up anymore.

As others wrote, the gyroscopes stability has nothing to do with it bending space-time. It's purely Newtonian physics:

 

[m4r35n357]

If not then what is that?

OK, you did ask! You will need to forget pretty much everything you have posted above if you want to learn more. Look for "Introduction to special relativity" on the web, try a few different ones to find one that suits your style and pace, and I would also strongly recommend staying away from YouTube altogether at this stage!

 

[nipoleon]

I'm sorry, I've been watching too much NOVA and science shows all these years. I thought that was a real thing.

 

[phinds]

I'm sorry, I've been watching too much NOVA and science shows all these years. I thought that was a real thing.

Sadly, they are not. I watch a lot of such presentations because they have neat graphics and pretty pictures but I've learned not to take the "science" seriously AT ALL. They do get a lot of stuff right but they get huge swaths wrong and you'll never know which is which if all you "learn" from is such shows.

 

[Ibix]

I'm sorry, I've been watching too much NOVA and science shows all these years. I thought that was a real thing.

The problem with anything outside scientific journals was summed up for me by a guy who worked on GM crops. He said the problem with journalists is that they ask questions but don't listen to the answers. If they do listen, they don't understand. If they do understand, they write something which goes to an editor who didn't get where he is by listening to answers or understanding them.

I've heard variants on this from specialists in non-scientific fields as well - the GM guy just had the pithiest version of it. Primary sources, direct communication from experts, or professional journals are just about the only things worth consulting for anything more than a very general overview of anything, as far as I can tell.

 

[PAllen]

Its worth noting that a gyroscope and its supporting tower weigh the same when the gyroscope is _apparently_ defying gravity as when its stationary. That because a gyroscope doesn't produce a force that counters gravity, it produces a torque.

Strictly speaking, this is not true. Kinetic energy contributes to (invariant) mass of a system, e.g. a box of hot gas weighs more and has more mass than a similar box of cold gas. You have added energy to the gyroscope to spin it up, so it will have more mass. The amount will be infinitesimal, of course.

 

[sweet springs]

Does a gyroscope on a small scale bend space perpendicular to the Earths bending and that's why it stays up? Once the gyroscope loses energy it's bending of space-time diminishes and it can't stay up anymore.

The reason why it stays up has nothing to do with beding spacetime. First saying so, the following is just a digression.
Newton's universal gravitation law tells us a gyroscope attract other mass. Though it is tiny not zero.
GR says gravitation generated by gyroscope depends on rotation. Rotating gyroscope and lying gyroscope show different spacetime bending nature. In BH case the former is Kerr BH and the latter is Schwartzshild BH.

 

[FactChecker]

I seriously doubt that anything in NOVA would lead to misconceptions of the magnitude we are dealing with here. I think that the OP is trying to fill in gaps in his knowledge using his own imagination. That's admirable, but a hopeless task -- it took many geniuses to get to the truth. One must rely on further reading and on discussions like this thread. The OP is taking the right steps by using this forum.

 

[Nik_2213]

The subtle, but totally Newtonian math of a gyroscope continues to bemuse woosters, has humbled otherwise expert folk:
UK's Prof Laithwaite probably the saddest, saddest example there-of...
https://en.wikipedia.org/wiki/Eric_Laithwaite
I saw the original lecture on TV: IMHO, the wiki rather understates his 'Crash & Burn'...

FWIW, journalists and their editors often require the application of proverbial '4x2 clue' before they'll take heed of your printed hand-out, never mind what you actually said 'on the record'...
I still shudder at memory of my employers discovering I was an amateur Astronomer, with a particular interest in our 'nearby' stars.
( Then a BIS member, I was actually interested in exo-planets, but this was in the barren gap between Van de Kamp and 'Hot Jupiters'... )
The 'house magazine' draft article had me down as an enthusiastic amateur Astrologer.
I corrected the draft, they changed it back.
I corrected the draft, they changed it back.
I corrected the draft, they changed it back.
Took me a lot of time and trouble, plus a serious rant, to convince that purblind crew that there was any difference, never mind a 'Formal Complaint' insult...