Questions tagged [machs-principle]
Use this tag for Mach's principle. DO NOT USE THIS TAG for the Mach number!
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1answer
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Differentiating linear and non-linear motion
If there is a Person sitting in a vehicle which is moving, how could he find out whether it's in motion and if he figures that out, how does he find out whether it's accelerated or non-accelerated?
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1answer
63 views
Super luminal speed paradox? [duplicate]
Chosing a reference frame in which the Earth is at rest and doesn't rotate is related, but different. Here I'm asking if there is a paradox and if my attempt at resolution has merit, and if not ...
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0answers
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Gravity: Inverse square law over extreme distance [duplicate]
I'm just an enthusiast, with a gap in my knowledge of physics. Please don't hesitate to be brutal, I would really like to know where I'm wrong.
Thank you!
Rockets gain speed if they launch East ...
3
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0answers
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Do gravitational waves disprove shape dynamics?
Mach's Principle loosely states that nothing can happen in empty space. Shape dynamics (https://en.wikipedia.org/wiki/Shape_dynamics / https://arxiv.org/abs/1409.0105) is a formulation of GR that is ...
24
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4answers
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Would there be centrifugal force if I were alone in the universe? [duplicate]
When I'm rotating, I feel centrifugal force.
But if I were the only one in the universe and rotating, wouldn't I just kinda be still (since I'm not rotating with respect to anything) or would there ...
3
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3answers
114 views
Earth's rotation in an empty universe
I have read these questions:
Is rotational motion relative to space?
Rotation in an 'empty' universe
None of these talk about whether we can and how we can determine rotation of Earth ...
4
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1answer
132 views
Newton's Bucket, Artificial Gravity, Absolute Rotation, and Mach's Principle
I have been trying to understand how we can talk about absolute rotation in general relativity. I get that it is an area of active debate with some adherents of Mach's Principle and others believing ...
3
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0answers
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To what extent is rotation relative (in GR and other theories)?
In Newtonian physics, rotary motion is absolute even though linear motion is not. More recently, there has been a hope that rotation can also be shown to be relative.
Two definitions of relative
A ...
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0answers
48 views
Does the Moon travel faster than the speed of light when I turn my head? [duplicate]
Let's say I turn my head 90 degrees to the right.
Can I consider that my head is standing still and that everything else in the Universe is turning 90 degrees to the left with respect to it?
If I ...
1
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1answer
74 views
Mach's principle and infinite speed of distant stars
If rotation was relative, we could say that the Universe is revolving around the earth. But how could this be true, since at some distant point the speed of a star would be greater than the speed of ...
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0answers
58 views
Why is angular motion special?
I'm a biochemist, and not a physicist so bear with me if I say something stupid. I do like to read about physics, though and this is one thing I can't wrap my head around.
I was recently reading ...
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1answer
88 views
How can I interpret or mathematically formalize Maxwellian, Leibnizian, and Machian space-times?
I've been reading the book, World Enough and Space-Time, and I came across a rough list of classical space-times with varying structural significance.
Here is the same list, minus Machian Space-time,...
1
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2answers
181 views
Do absolute space and time exist? [duplicate]
Einstein's theory proved that most properties of a body are relative to something and are not absolute. I am still wondering if physicists still think that there is a way that Newton's absolute space ...
2
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1answer
62 views
Atom interferometry,gravity and inertia: What can it measure that light interferometry can't? [closed]
What previously unexplored effects in gravity and inertia can be examined with atom interferometry in ways that hasn't already been done through light interferometry?
Can atom interferometry be used ...
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0answers
73 views
Massless Electrons and Effect on Graphene Mass
I've read that electrons in graphene can travel masslessly, due to the effect of the graphene crystal around them. I'd also read that the application of an electric field can change this behavior and ...
4
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0answers
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Is Weinberg wrong in this account of how Mach's principle is incorporated in general relativity?
In his book "Dreams of a final theory" pg.144 Steven Weinberg says
"the circulation of the matter of the universe around the zenith seen by observers on a merry-go-round produces a field somewhat ...
3
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1answer
103 views
Can empty space rotate without frame dragging?
A recent question Rotation of our Galaxy's inertial frame is about an observational evidence of the space rotation. My question is if such a rotation is conceptually possible in GR. Can we assume ...
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1answer
80 views
Rotation of our Galaxy's inertial frame
Suppose in the universe, there are inertial frames in the vicinity of galaxies. Suppose also that these frames rotate slightly with respect to each other - that the universe is not quite a 'mill pond'....
2
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1answer
68 views
Why there is a preference between different reference-bodies?
I know a classical mechanics law points out the following (Newton's first law): material particles with constant velocity will continue to move uniformly in straight line. If material particles are in ...
13
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2answers
1k views
How can Newton's idea of absolute space be reconciled with Galilean relativity?
I wasn't sure if this might be better suited to History of Science and Mathematics SE, but I suppose it is a bit more 'science-y' than historical.
Apparently Newton believed in absolute space and ...
1
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1answer
113 views
Why is Brans-Dicke Theory considered as a failed attempt to incorporate Mach’s principle in a relativistic theory of gravity?
In Generalized Brans-Dicke theory: A dynamical systems analysis by Nandan Roy and Narayan Banerjee, Brans-Dicke theory is described as a failed attempt to incorporate Mach’s principle in a ...
4
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1answer
372 views
How can you tell if a given reference frame is inertial? [duplicate]
An inertial reference frame is one in which a particle has constant velocity if and only if has a zero net force acting on it.
How can one determine if a given reference frame is inertial? For ...
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2answers
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Are laws of physics (mechanics) symmetric under uniform rotation?
I'm just starting to learn about symmetry. I understand that physical laws are symmetric under translation and consequently (is it not a consequence?) under uniform velocity in a straight line.
I see ...
2
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1answer
74 views
Rotation inside a black hole
As far as I can see most of the questions about rotation of a black hole refer to the appearance of a hole to an outside observer.
What about the region within the Schwarzschild radius?
According ...
2
votes
2answers
299 views
What is the solution to Newton's bucket problem?
What is the solution to Newton's bucket problem?
The Wikipedia page does not give me any finality.
After reading, I felt as if the problem implied either one of these two things
There is a special ...
2
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2answers
103 views
Question concerning the cause of the rise of water in a spinning bucket in empty space according to Mach
According to Mach we can attribute the fact that in a spinning bucket with water the water rises to the edges of the bucket just as well to the whole Universe rotating around the bucket, as to the ...
4
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2answers
104 views
Two masses in empty space
Consider two equal point masses which are rotating circular arround each other in empty space for ever (radiation effects are ignored).
Let an observer be at the center of mass of the system. Then, ...
0
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1answer
137 views
Equation for shape of water drop on hydrophobic surface
What would be the general equation of the 3D shape water forms when it "beads up" on a hydrophobic surface such as wax paper?
4
votes
2answers
330 views
Is the pressure higher in the corners?
I was watching the video The Ingenious Design of the Aluminum Beverage Can. At 20'', the author says
[..] a spherical can [..] has no corner, so no weak points because the pressure in the can ...
0
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1answer
105 views
Would the Earth stop spinning in the absence of stars?
Please explain this in layman's terms.
A cosmos without stars would have no spacetime structure relative to which the earth could spin. For there to be gravitational (or inertial) fields capable of ...
8
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3answers
666 views
What is “a general covariant formulation of newtonian mechanics”?
I am a little confused: I read that there are general covariant formulations of Newtonian mechanics (e.g. here). I always thought:
1) A theory is covariant with respect to a group of transformations ...
0
votes
2answers
65 views
Wheel versus Sphere: Traveling Linearly Down a Track
Assume the following:
A tire-like wheel and sphere are both of diameter d and mass m
They are both made of the same material
They are both resting at the apex of an inclined track
An equal amount of ...
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0answers
223 views
Frame dragging VS Mach's principle: rotating body in an empty universe
What I understand about Mach's principle VS modern physics:
According to classical physics, there are ways to distinguish weather a body is rotating or not. For example if it is rotating, the ...
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4answers
483 views
Will accelerated observer see radiation from the charge that is at rest in observers's frame?
So I had a huge debate about this with my friends. Imagine that you are in a non-inertial frame of reference. For simplicity, assume that frame is accelerated along x-axis. You have held a charge in ...
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4answers
578 views
Rotational relativity? Is there an universal frame of reference for rotation?
So, there is obviously no such thing as an universal frame of reference for velocity. According to the relativity theory, there is no difference between two observers moving with respect to each other,...
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6answers
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How does a spinning object “know” that it is spinning?
I am constructing a thought experiment about a spinning object that is floating in intergalactic space. I assume that this object is about the size of a planet so that it will have enough gravity so ...
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2answers
353 views
The relation between acceleration and inertial force
Acceleration causes inertial force, and it is not relative, but why?
What is the reason for feeling inertial force by acceleration?
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1answer
94 views
When we spin and feel our arms fly, is it the effect of gravity?
If accelerating reference frames can be treated as normal inertial reference frames but with gravity, then for a rotating reference frame, is the centrifugal force = gravity? More specifically, I was ...
3
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1answer
112 views
Does a similar concept like centrifugal force exist for the whole universe? [duplicate]
Is it meaningful in the sense of falsificable to ask whether the whole universe (including everything known/observable: cosmic background radiation etc ..., excluding everything not directly ...
3
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0answers
129 views
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 ...
4
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1answer
112 views
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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0answers
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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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0answers
71 views
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 ...
13
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5answers
3k views
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 ...
6
votes
2answers
946 views
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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1answer
145 views
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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7answers
649 views
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 ...
3
votes
1answer
1k views
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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0answers
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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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7answers
6k views
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 ...
