Questions tagged [tidal-forces]

Questions about the apparent force stretching a body towards and away from the center of mass of another body due to the variance in acceleration due to gravity

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Difference between fluid Love number and tidal Love number

I'm trying to understand more about tidal deformation in planets, and I frequently encounter Love numbers. However, sometimes the fluid Love number is mentioned, and sometimes the tidal Love number is ...
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Is the high-low tide difference greater, on average, at new moon, full moon, or neither?

The difference between high tide and low tide peaks when the moon is full and also when the moon is new. At both of these points in the lunar cycle, the tides are known as "spring" tides. On ...
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Relative orientation in a 1:1 resonance of a planet and a satellite

To my understanding, in a two-body problem of a planet and a satellite, a 1:1 resonance means that the orbital period of the satellite is the same as its angular frequency (maybe not, so please ...
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How can Io be tidally heated while it is in tidal lock?

According to its Wikipedia page: Rotation period: synchronous Eccentricity: 0.0041 But also ...extreme geologic activity is the result of tidal heating... How is it possible? It should not be ...
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Physical Meaning of the Principal Tidal Fourier Modes and Their Integers

I'm trying to understand tides evolution of planets, and I often come across the Prinicipal Tidal Fourier Modes expressed as: $$ \omega_{lmpq}$$ For example, see the discussion after Eq. A15 in ...
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Can we measure planetary Love number of exoplanets?

I understand that Love number is the ratio between the tide raising potential to the actual deformation of the body, however, I'm not sure if there are ways to detect the Love number from observations ...
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Is there any difference between tidal locking and synchronous rotation?

I'm trying to understand more about orbital mechanics, and I'm encountering a few terms which I'm not sure if they are exactly the same. The two terms are Tidal Locking and Synchronous Rotation. To my ...
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Why does the difference between terrestrial times and universal time, $\Delta T$, have such a strange behaviour?

I was reading about ancient astronomy, and one of the main phenomena described is eclipses. Now, I read this 2016 paper by Stephenson, Morrison and Hohenkerk, in which they determine the values of the ...
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What would I experience on a planet orbiting close to a black hole? [closed]

I can't get my head around it completely. I am standing on an Earth-sized planet circling a black hole. Let's assume the planet to be an incompressible one. It is observable that matter is sucked in ...
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If we replaced the Moon with Ceres, how close would Ceres have to orbit to cause the same tides?

How close to Earth would Ceres have to be to cause tides of the same strength as by the Moon, above the region it orbits? Ceres has 1.3% the Moon's mass, but that doesn't mean it must be at 1.3% the ...
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Understanding various conditions where a star and a black hole meet and there is no tidal disruption; what all can we infer from this diagram?

Can an entire star pass through the event horizon of a black hole unharmed? is a one sentence HNQ with an amazing (to me at least) answer: for supermassive black holes larger than roughly 100 million ...
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Tidally locked Venus, is it possible and consequences?

Suppose, Venus becomes tidally locked. Will its dark side cool enough so that the CO2 from the atmosphere to precipitate in liquid form to make an ocean? Also, I wonder, how close Venus is to becoming ...
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Calculating the radial tidal amplitude on a planet from the fluid Love numbers

How do you calculate tidal amplitudes from the fluid Love numbers? In my course on planetary physics I saw an approximate expression for the displacement from equilibrium tide: $$\Big|\frac{V_T}{g}\...
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If you are standing on the shore and it is high tide, what are the two possible locations for the moon relative to where you are? [duplicate]

Science Class If you are standing on the shore and it is high tide,
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Lunar Inclination

Are there published tables for Lunar Inclination? I am interested because I believe this determines the degree of "Diurnal Inequality" of tides. There are tons of publishes tables of tides ...
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Is there a way to estimate or calculate the tidal range induced on a water-bearing planet?

Consider a system in which a central star is orbited by a planet with liquid water oceans, which is itself orbited by a moon. Given the masses and distances between these three objects, is there some ...
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How to explain tidal tails and dark matter sub-halos in simple terms?

There is the exciting news by ESA entitled Is the nearest star cluster to the Sun being destroyed? Data from ESA’s Gaia star mapping satellite have revealed tantalising evidence that the nearest ...
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How much lighter would someone be on the Jupiter-facing side of Io?

Io is the Galilean moon closest to Jupiter. Its average surface gravity is 0.183g and it has a tidal lock with Jupiter. So if you stood on the near side of Io at the equator, how much lighter would ...
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Do moons of rocky oblate planets migrate to low inclination over time? If so, does the time it takes depend on the Moon's size?

Discussions elsewhere suggest that this happens and that smaller moons would tend to low inclination with respect to the planet's equator faster than larger ones. For example, Mars' small moons are ...
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A moon in eccentric orbit dipping below Roche limit

Let's imagine (or do we know one?) a moon in a very eccentric orbit around a planet, with periapsis below the Roche Limit. How would it behave? Would it break apart when speeding past the planet, then ...
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Can moons exist inside a planet's roche limit?

Saturn's rings are inside its own Roche Limit - the limit beyond which bodies start disintegrating due to the tidal forces of the parent body. But as every rock in the ring can be regarded as a ...
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Is a three body gravitating system doomed to collapse?

Suppose we have two gravitating bodies, which are rotating around each other. They are bodies and are affected by deformation caused by tidal forces. Moving tidal waves suck energy from the axial ...
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The possibility of rapidly changing the Earths orbit via a passing astronomical object

I assume that the Earth could be “gently” (without colossal tidal or volcanic catastrophe) displaced by a passing extra solar star, brown dwarf or planet and end up perhaps 10% further away from the ...
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Why doesn't Earth's leading tidal bulge cause the Moon to start spinning in the opposite direction than its original spin?

Please refer to the image below: My question is, why doesn't Earth's leading tidal bulge (encircled in the green circle 1) pull on the moon's tidal bulge (encircled in green circle 2), leading to a ...
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Considering that the moon’s gravitational pull on earth is so weak- we need special instruments to detect it- how does it cause the tides?

That the moon’s gravitational pull is responsible for the tides is established. However, if we want to detect the moon’s gravitational pull on earth, this is very challenging. This seems to be a ...
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How high were the tides back when the Moon was much closer to Earth?

In this article it is stated that the Moon was originally much closer to Earth at a distance of 22,500 km rather than the 384,400 km it is today. What was the height of the tides back then in meters? ...
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Would a satellite that has a retrograde orbit and a shorter orbtial period than its planet's rotational period be tidally accelerated or decelerated?

There are 4 configurations to consider. A satellite orbiting a planet that: Has a prograde orbit and larger orbital period than its planet's rotational period (example: The Moon) Has a prograde ...
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Does a rotating moon experience greater tidal heating than a tidally locked equivalent?

Tidal heating of a tidally locked moon is relatively straight forward to calculate, even though details of its internal structure is hard to work out in the first place. By contrast, tidal heating due ...
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How does using Tidal energy affect the moon?

Reading another question Where do we have it from that the Moon is migrating away from Earth? I makes me ask what effect does harvesting tidal energy for electricity production have on the rate the ...
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What's the equation for moon-moon tidal heating?

Between a moon and the primary, the equation for tidal heating is: $$\dot E_\mathit{Tidal} = - Im(k_2) \frac{21}{2} \frac{GM_h^2 R^5 n e^2}{a^6}$$ But how does one calculate the tidal heating between ...
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Can tidal locking increase rotational kinetic energy? Where does the energy come from then? [closed]

I was thinking about the explanation for how the Moon gets tidally locked with the Earth. We are working in the non-rotating reference frame of the Earth, and assume it is inertial (to an approximate ...
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Why don't the inner moons of Jupiter have tidally-induced volcanism?

Volcanism on Io is caused by the fact that it is tidally heated. There are four moons that are closer to Jupiter than Io with higher eccentricities, yet they don't seem to have any volcanism at their ...
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Why do tides reach a peak two days after the solar eclipse?

On June 21st we, in India, experienced a total solar eclipse. Based on my basic understanding of why tides occur, the tidal forces by moon and sun add up and the tides will be maximum on the day of ...
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Why are there no terrestrial planets with a subsurface ocean?

Subsurface oceans in satellites are pretty common: Europa, Enceladus, Ganymede, Callisto, maybe Pluto... This is due to tidal heating of their host planet, Jupiter and Saturn, which heats up the inner ...
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Does Saturn raise tides on Titan's lakes?

Titan is the only body in the Solar System other than Earth to have large bodies of surface liquid. Since Saturn is much more massive than the Moon, I would expect for tides, if they're present to ...
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How strong are the tides raised by Io on Jupiter relative to the ones raised by the Moon on Earth?

There seems to be 2 ways of calculating tidal forces that appear contradictory. Either: By calculating the difference of Io's gravitational acceleration on a point on Jupiter's near side and the ...
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If Saturn's rings cannot coalesce into a moon because of tidal forces, then how are shepherd moons able to exist?

From Wikipedia: In celestial mechanics, the Roche limit, also called Roche radius, is the distance within which a celestial body, held together only by its own force of gravity, will disintegrate due ...
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How will the Solar tides affect the Earth's rotation once it is tidally locked to the Moon?

It is my understanding that the tidal forces of the Moon acting on Earth cause it to slow down its rotation and, because angular momentum is conserved, the Moon's orbit subsequently expands. This ...
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Can you create an orbit in a space station using balls?

Would it be possible to spin a ball in a space station, and for it to create its own orbit for a smaller ball to rotate around it?
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Why do planets in red dwarf star systems tend to have a higher probability to get tidally locked?

I have read about about the habitability of red dwarf systems on Wikipedia, as well as some web articles on similar topics. The problem is, it does not explain why and how it happened. Google search ...
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Is the process responsible for Triton's nearly perfect circular orbit going to happen in my fictional world?

First of all, I'd like to point out that I'm a worldbuilder and I like my worlds to be as physically possible as... possible. I am in the process of building a world with a habitable moon orbiting ...
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Vectorial construction of tidal forces - or why is it centripetal at low tide

I am seeking to understand why the tidal force is pushing towards the center of the earth (centripetal), at a point that is making with the center of the earth a 90º angle to the moon-earth axis. ...
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Scientific possibility of stationary moons for a writer of fiction

I tried to do some research to find an answer for this question before posting this but didn't find anything that I could sink my teeth into. I was wondering: if it would be possible for a planet to ...
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Hills' mechanism for making Hypervelocity Stars

In Hill’s mechanism, the gravitational tidal force of a single MBH disrupts an approaching binary. One star is captured on an eccentric orbit around the MBH and, by conservation of energy, the ...
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Where does Love's number come from in $\delta m = \frac{1}{2}k_2M_2\lbrace\frac{R_1}{r_\star}\rbrace^3$, the formula for the mass of a tidal bulge?

My question refers to page 165 of this paper. Specifically, how does one derive the equation $\delta m = \frac{1}{2}k_2M_2\lbrace\frac{R_1}{r_\star}\rbrace^3$ for the mass of a tidal bulge? A full ...
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Derivation of a formula for the mass of a tidal bulge and tidal torque

I've been looking into the tidal mechanism for a binary star system and seem to have hit a brick wall. In the literature (see below), little explanation is given to justify the equations (9.60), (9.61)...
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How does the Moon's gravity affect Earth's oceans despite Earth's stronger gravitational pull?

Given that Earth has a much stronger gravitational pull than the Moon, how does the Moon have any influence on Earth's oceans?
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Why the torque exerted by the moon upon the Earth makes the Moon to increase his orbit? [duplicate]

For what I know, this torque exists because of the misalignment of the tidal bulge with the apsidal line Earth-Moon a certain angle $\alpha$, which makes the earth rotation to slow down a bit. But, ...
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Why would tidal forces on planets become more intense when a star becomes a white dwarf?

I was puzzled by this press release by the Royal Astronomical Society: "Small, hardy planets most likely to survive death of their stars" - phys.org, May 14, 2019 Astrophysicists from the Warwick ...
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Question about tidal forces and the Roche limit

As we know, an object that is beyond the Roche limit doesn't disintegrate (obviously) because the tidal forces upon the object are weaker than the gravitational pull of the object towards its centre, ...