Questions tagged [machs-principle]

Use this tag for Mach's principle. DO NOT USE THIS TAG for the Mach number!

81 questions
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Is the equivalence principle Machian?

There is a lot of discussion on the subject of Mach's principle, and whether it has any place in the theory of relativity. But it seems to me that one could argue that Mach's principle is at the heart ...
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Is it possible to tell which way a Universe is spinning?

Imagine a Universe spinning on the x-axis. So there is a centripetal directed away from the x-axis. According to General Relativity this is entirely equivalent to a non-spinning Universe with a ...
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The Inertial theory of Sciama and an electromagnetic analogue

In 1952 D. W. Sciama introduced a paper On the origin of inertia. It presents a method in which inertia could arise from other mass in the universe. It goes along these lines: If you try to ...
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Neck size of wormholes in shape dynamics

As far as a dilettante like me knows, in shape dynamics, black holes are really wormholes. What it the expected diameter of the necks of such wormholes (both for regular holes resulting from the ...
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How does one determine an inertial frame?

How does one determine whether one is in an inertial frame? An inertial frame is one on which a particle with no force on it travels in a straight line. But how does one determine that no forces are ...
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Understanding Mach's principle: What does it answer?

What is the question that Mach tried to address in his principle? I mean, we know how to detect the inertial and non-inertial frames (by Newton’s law). Once this is understood we also see that due to ...
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Is this the reason why acceleration is said absolute?

I've seem sometimes people saying that although uniform motion on a straight line cannot be detected and hence it is not absolute, acceleration is indeed absolute in Classical Mechanics (I don't know ...
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Absolute (as opposed to relative) concept of inertial frame

In mechanics there is a relative concept of "inertial frame": frame A is inertial with respect to frame B if A moves uniformly with respect B. That concept is easy to understand. There also seems to ...
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If reality is relative, then what about Newton's bucket argument?

There is nothing outside the universe. - Lee Smolin So, there can't be any absolute frame. Everything must be measured relative to an entity that exists in the universe. Thus, space is ...
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Can I choose any reference frame? [duplicate]

I'm a horrible noob at anything past mechanics, so please bear with me. According to Einstein's theory of relativity (at least as it is known in "popular science" (lowercase)), mass-full objects can'...
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Why does rotation simulate gravity if motion is relative?

In Einstein's theory of relativity, if motion is truly relative, then why would somebody in a rotating space station experience (artificial) gravity? I mean, I get why they experience gravity IF the ...
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Mach's principle in empty universe, centripetal force and violation of Newton's laws of motion [closed]

Questions about Mach's principle and empty universe has been asked many times but nowhere can I find it's cross examination with centripetal force. From my point of view the simple logic of ...
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If Julian Barbour is Correct, is the Speed of Light Special?

According to this article in Discover Magazine, Albert Einstein's Theory of Relativity is wrong, because it didn't fully live up to the ideas of Einstein's idol, Ernst Mach. Mach proposed a truly ...
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Having trouble understanding how the centrifugal force works

I thought that I understood the centrifugal force earlier, but I can't seem to grasp how it interacts when considering that everything is relative? Let's imagine that you are the only one in the ...
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How does one refute a Machian mechanism for inertial emergence?

Introduction: Consider the diagrams representing the duality between the weak and strong principles of equivalence. Now based on how these diagrams were taught to us (at least how they were taught ...
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Why are some things attracted to you but others repelled by you in rotating reference frames?

Note that my understanding of general-relativity is rudimentary. If I understand right, it means that basically any reference frame can be considered stationary, but there may be random gravitational ...
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Is there a distinguished reference system, after all?

The equivalence principle, being the main postulate upon which the general relativity theory rests, basically states that all reference systems are equivalent, because pseudo forces can (locally) be ...
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What is the Earth truly rotating about/revolving around?

Earth rotates on its axis and revolves around the sun, the sun revolves around the galaxy, the galaxy is also moving. So Earth's net rotation as observed from a fixed inertial frame consists of all ...
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If matter creates space, shouldn't there be experimentally detectable consequences?

Ernst Mach, a man to who influenced Albert Einstein significantly in his approach to relativity, did not quite seem to believe in space as a self-existing entity. I'm pretty sure it would be correct ...
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What's the deal with the gyroscope?

In this article ("The problem with physics", Tony Rothman, ABC science) the author says in the 5$^\textrm{th}$ paragraph: For example, one needs only first-semester equations to describe reasonably ...
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What is the present state of Mach's Principle amongst physicists? [duplicate]

Possible Duplicate: Is Mach’s Principle Wrong? I'm doing research on gravitation and inertial forces and would like to know what is the place that Mach's Principle is occupying nowadays in the ...
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Rotation in an 'empty' universe [duplicate]

Possible Duplicate: Is rotational motion relative to space? Assume a universe with the same physics as ours, but containing only one rotating (charge-free) body - let's say the size of the Earth. ...
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Would the arms of a rotating ice skater still move outwards if there was no other object in the universe?

If there is no other object in the universe apart from a rotating ice skater, then nothing can be used as a reference frame. Would it make any sense to say that the skater is rotating? If so, rotating ...
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Inertia in an empty universe

I was reading a recent article on Mach's Principle. In it, the author talks about inertia in an empty universe. I'll quote some lines from the article: Imagine a single body in an otherwise empty ...
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How do we explain accelerated motion in Newtonian physics and in modern physics?

Maybe my question will seem stupid, but I am not a physicist so I have some problems understanding a classic Newtonian experiment: in the bucket experiment, why does he have to introduce the absolute ...
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Is Mach's Principle Wrong?

This question was prompted by another question about a paper by Woodward (not mine). IMO Mach's principle is very problematic (?wrong) thinking. Mach was obviously influenced by Leibniz. Empty space ...
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Is the Woodward effect real?

Did anyone ever heard about this?I've never seen any serious physicist talk about "mass fluctuations". Here is the man in his own words: http://www.intalek.com/Index/Projects/Research/woodward1.pdf ...
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Newton's Bucket [duplicate]

Newton's Bucket This thought experiment is originally due to Sir Isaac Newton. We have a sphere of water floating freely in an opaque box in intergalactic space, held together by surface tension and ...
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What determines which frames are inertial frames?

I understand that you can (in principle) measure whether "free particles" (no forces) experience accelerations in order to tell whether a frame is inertial. But fundamentally, what determines which ...