Questions tagged [tidal-effect]

The force on parts of an extended body in a non-uniform gravitational field, due to residual gravitational attraction between the overall effect on the body and the expected effect on the point in question. Tidal forces are most notably in large moons orbiting near their primaries.

Filter by
Sorted by
Tagged with
4
votes
1answer
89 views

Are black holes affected by tidal forces?

I've recently read about the last parsec problem, which states that supermassive black holes should not be able to merge within the current age of the universe. Once they reach a distance of about one ...
0
votes
2answers
52 views

Buoyant force of tides and conservation of energy [duplicate]

Imagine an electric power generator in a form of a floating object moving up and down and utilizing the buoyant force of sea tides. Can anyone explain how it doesn't violate the principle of ...
-1
votes
1answer
36 views

Is mass slowly destroyed when force of gravity is applied? [duplicate]

This may seem like a far fetched idea, but consider this system. Imagine a simple system of just the Moon orbiting around the Earth, creating low tides and high tides with its gravity. Now imagine ...
1
vote
2answers
37 views

How much do ocean currents alone slow Earth's rotation?

Tidal friction is commonly spoken of as the reason for the slowing of Earth's rotation. What if the moon didn't exist? We would still have ocean currents and wind due to the Coriolis effect and the ...
2
votes
7answers
193 views

Can we feel gravity while free falling?

I watched some video saying that there is still gravity in space station and almost same strong as it on Earth, the reason they feel no gravity is because the centrifugal force of the orbit is same as ...
0
votes
2answers
34 views

Are the tides scale independent?

What I mean is the following. Imagine two smooth massive spherical bodies ($M_1\neq{M_2}$), with equal and homogeneous mass densities. Both masses have a layer of water on them for which holds ($R_1$ ...
3
votes
2answers
72 views

Could the moon move balls on perfectly flat and level surface?

I've been looking into the concepts of highly flat surfaces and highly round objects, and I'm wondering if an experiment like this would work / has been done: Take a perfectly flat surface Level it ...
6
votes
1answer
145 views

Will extracting power from ocean tides affect the moon's orbit in the LONG run?

Conservation of energy says that any energy extracted from our ocean's tides would have to come from somewhere. Since these tides are a gravitational effect due to the moon, it would seem that the ...
3
votes
1answer
57 views

Could harm due to spaghettification be mitigated by entering a black hole at almost the speed of light?

Say that we wanted to send a probe into a black hole, perhaps hoping to see if it's actually a wormhole that might transport the probe elsewhere. Upon approaching a black hole, the probe would ...
1
vote
1answer
57 views

Definition of “tidal forces”

May anyone give me definition of tidal forces? Topic is related to force between two celestial bodies which are tidally locked. I have never heard for such force. Here is quotation which is intriguing ...
0
votes
1answer
30 views

Will we be able to experience huge waves one after the other if we were near a strong gravitational field?

I was wondering if we will have huge waves due to the presence of a strong gravitational field nearby earth? If our planet is rotating around the gravitational field, is there a possibility for ...
39
votes
6answers
8k views

Why aren't satellites disintegrated even though they orbit earth within earth's Roche Limits?

I was wondering about the Roche limit and its effects on satellites. Why aren't artificial satellites ripped apart by gravitational tidal forces of the earth? I think it's due to the satellites being ...
1
vote
1answer
54 views

Given that the Moon affects tides and most of the human body is water, do tides affect people?

It is known that the Moon causes tides. Given that the human body is 60%-70% water, is there any research that shows that the tides affect humans in any tangible way? If this is not the appropriate ...
0
votes
1answer
110 views

Pushing a long stick into the event horizon [duplicate]

Imagine a very long continuous stick with one end being pushed into the event horizon, all outside observers must agree that this end of the ruler come to a complete halt while I'm still pushing at ...
0
votes
1answer
67 views

Will tidal effect make physics laws different?

I was reading Wheeler & Taylor's Spacetime Physics. The authors mentioned about tidal effect, as well as all physics laws are same in free-float frame. I am left wondering if tidal effect will ...
3
votes
2answers
74 views

Tidal force of a black hole without using tetrad

One thing I have been somewhat curious about is computing geodesic deviation for tidal effect. Specifically, given separation vector $\xi^a$ between two nearby timelike geodesics and $V^c$ the ...
1
vote
0answers
61 views

When will a person falling into a black hole be crashed by tidal forces?

Assume that a person can resist $30g\approx 300\frac m{s^2}$ (remark: the record is actually at 46.2). I want to solve for the distance $r$ at which a $1.5m$ tall slim person falling radially into a ...
0
votes
1answer
68 views

Does the Jerk (derivative of acceleration) play a significant role in relativity?

In particular, I'm thinking of spaghettification that occurs as an object falls into a black hole (as an extreme example). But what about tidal forces like the tidal heating taking place on Jovian ...
3
votes
1answer
60 views

Can a spacecraft use the planet's gravitational gradient to boost it's orbit without rockets?

A spacecraft orbits a planet. It extends a mass about a horizontal direction on a long tether. At this point there is not much gravitational gradient between the craft and the ejected mass so there is ...
2
votes
1answer
93 views

Why does a tidal bulge result in a net torque on the Moon?

I understand that a tidal bulge is caused because the side of the earth facing the moon experiences a stronger gravitational force than the other. This results in the oceans on that side slightly ...
1
vote
2answers
60 views

If you fell into a black whole with an accretion disc, but perpendicular

If you fell into a black whole with an accretion disc, but orthogonal to the plane of the disc - would you ever meet the disc? I'm not asking whether you survive long enough, and obviously we assume ...
0
votes
1answer
91 views

Is gravitation on earth less in nighttime than in daytime?

I have been thinking on the effect of the centrifugal/centripetal forces from the orbital movement of the earth around the sun, which might perhaps affect the gravity. In nighttime we are on the ...
3
votes
0answers
99 views

Tidal acceleration of a body at rest in a Schwarzchild geometry using geodesic equations

I'm self-studying the properties of a Schwarzchild geometry, with line element $$ds^2 = \left(1-\frac{2m}{r}\right)dt^2-\left(1-\frac{2m}{r}\right)^{-1}dr^2-r^2\left(d\theta^2 + \sin^2\theta d\phi^2\...
0
votes
0answers
61 views

Is the shell theory, at least in concept, applicable to a ring world?

The Shell Theory tells us that inside a homogeneous sphere there is no gravity. It seems to me that if you cut off the top and bottom of the sphere and leave a ring, equal in width from the equator ...
1
vote
0answers
27 views

If the Earth would change into a ball of water, how wil its form develop, considering only the Sun's and Moon's influence? [duplicate]

Let's fantasize that the Earth changes in a non-rotating ball of water. And let's assume the only gravitational influences on it are those of the Sun and Moon. What will happen to the form of the ...
1
vote
2answers
106 views

What happens to the water on the surface of the Earth if the Earth is not rotating about its axis in the Earth-Moon system?

Suppose the Earth is not rotating. As usual, the Moon follows its normal path around the Earth. Let's assume it's a circular motion and that there are no other gravitational influences. A test ...
1
vote
1answer
41 views

What would happen to a person's body if they entered a black hole? [duplicate]

One of the premises of the classic sci-fi show Farscape is that a person could travel through black holes, I'm curious as to what exactly would happen to a person body if you were to enter a black ...
2
votes
1answer
58 views

Where does the energy from tidal power plants come from? [duplicate]

Tidal power plants taps into the energy in the motion of the oceans due to the gravitational interaction between the earth and the moon, so much is clear to me. This question is about where would this ...
1
vote
3answers
362 views

Why is angular momentum of the Earth/Moon system conserved?

Why is the angular momentum of the Earth/Moon system conserved, apparently unaffected by external forces such as force of the Sun?
8
votes
3answers
1k views

How can the tidal force due to a black hole tear apart the observer inside?

I have heard that the tidal force of a black hole can tear apart an observer. But if the spacetime fabric is really stretched out near a black hole, isn't the observer also a part of it? Surely, he is ...
7
votes
3answers
2k views

Relative size of the 2 tidal bulges

I am interested in making a simplified model that represents only the effect that the moon has on Earths tides. In this model I am going to assume that the earth is completely spherical (with no ...
0
votes
3answers
107 views

Is the path that a planet takes orbiting the sun a centripetal one or one that follows a geodesic path?

Is the path that a planet takes orbiting the sun a centripetal one or one that follows a geodesic path? My point is that if the planet follows a centripetal path all objects on the planet will ...
0
votes
1answer
31 views

Difference between solar annual and solar daily earth tides

I understand there is a semi-daily and daily solar earth tides (S1,S2) because the earth is rotating around its axis. I understand there is an annual and semi-annual solar earth tides (Sa, Ssa) ...
0
votes
0answers
83 views

Deriving the expression for the static equilibrium height of liquids under tidal force

I have tried looking at various sources and Wikipedia articles. I also checked some Q&As here at StackExchange but I couldn't quite grasp how the formula for the height of tides is derived when we ...
3
votes
0answers
61 views

Understanding the tidal force tensor

I'm just looking to gain a basic intuitive understanding of the forces at work in tidal stripping and their direction/motivation etc. I'm struggling to grasp the underlying principles and it is making ...
2
votes
1answer
90 views

Where does the work come from if tidal forces are stretching elastic objects?

An elastic object e.g. a rubber band will be stretched in accelerated expanding FRW-spacetime during radial free fall in Schwarzschild spacetime by tidal forces due to Ricci- and Weyl-curvature resp.,...
2
votes
2answers
185 views

If gravity is not a force, how come it can produce potential energy?

From my poor understanding of Einstein's theory of relativity, gravity is not a force but the consequence of mass curving the space-time continuum. As such, the moon revolving around the earth is ...
0
votes
0answers
134 views

Calculate Height of Ocean Tides if Earth Had a Larger/Smaller Radius

For context, I'm coming at this question from the Worldbuilding stackexchange, where I've posted a related question. I'm not a physicist or scientist by training, so if I make any glaring errors, ...
0
votes
1answer
36 views

Debris ring formed from breakup of extreme-high rotation rate of rigid ring

In Larry Niven's Ringworld, where there is a rigid rotating ring with a radius of 1AU with the Sun at the centre, he introduces a fictional material "scrith", which apparently is strong enough to ...
3
votes
2answers
243 views

Would it be possible for a human to simply “step” through a traversable wormhole?

(For the purposes of a science-fiction story where the author is attempting to have as much basis in fact as possible) if one were to create or make use of a Morris-Thorne or similar traversable ...
0
votes
0answers
21 views

Are the high tides always more unequal when the centre of gravity is within a planet?

In case of our high tides at both sides of the Earth it seems that they are almost equal. But is there a slight difference because the center of gravity is about 1,700 km below the surface of the ...
1
vote
1answer
255 views

What happens inside the black hole?

I have learned that whenever an object gets inside a black hole, it traps the object and sucks it inside. After it had been swollen by a black hole, what would happen to the object inside it?
0
votes
1answer
95 views

Does the moon rotate around the earth-moon axis?

It is well known that the moon always shows the same side to the earth. But does the orientation of this side change? I.e. does the moon rotate around the moon-earth axis?
1
vote
1answer
54 views

Estimating the curvature tensor of spacetime using a rotating body

In curved space, you can define the Riemann curvature tensor at a point. In Riemann normal coordinates with that point as origin, the Riemann curvature tensor can be expressed as depending only on the ...
2
votes
2answers
147 views

Increasing distance between Earth and Moon [closed]

I have a problem where a planet's rate of rotation is decreasing due to tidal effects of the moon. I know that the angular momentum of the system will be conserved. So, in order to conserve that the ...
2
votes
1answer
86 views

How far apart are two initially $1000m$ separated bodies that fall to earth from infinity, when the closest body reaches earth?

Imagine two bodies (very, very small compared to the size of the earth), 1(km) separated from each other (in the direction of the earth) at infinity. After they reach earth after an infinite long trip ...
0
votes
3answers
330 views

Can the gravitational force between a 2D ellipse and a point mass in 3D space be found using the centre of mass of the ellipse?

I have a question where I need to find the gravitational force between an ellipse of negligible thickness and a point mass with given coordinates in 3D space. Not being from a physics background I ...
-2
votes
1answer
107 views

Rapid deceleration of the spaceship with the help of black hole [closed]

Could a spaceship traveling close to the speed of light (ok, maybe speed is not relevant for this question) decelerate (almost stop) very quickly (say, on a safe distance) with the help of a very ...
0
votes
1answer
66 views

Laplace's tidal equations

Do you know where to find a clear, pedagogical derivation of Laplace's tidal equations for the tidal elevation $\zeta$ and the velocities $u$ and $v$ of a fluid sheet located on a rigid body?
1
vote
1answer
273 views

Spaghettification inside a black hole?

Taylor and Wheeler in "Exploring Black Holes" calculate that the spaghettification time, measured from feeling a 1g tidal difference head-to-toe to disintegration at the singularity, is a constant, a ...