# 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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### Are there tidally locked bodies where the "far side" is denser?

It makes sense that tidal forces lead to tidal locking. Celestial bodies have varying densities and shapes, so some orientations have a lower gravitational potential, and eventually the tendency will ...
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### If Earth was a moon of Jupiter orbiting at the same distance as Metis (Jupiter's innermost moon), then how much lighter would a 100 kg person feel?

Metis is Jupiter's innermost moon, orbiting at a semi-major axis of 128,000 km. If Earth were to magically replace Metis, then how much lighter would a human weighing 100 kg be? There's no need to ...
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### Best way to quantify the tidal stress on an exoplanet?

I'm trying to assess the tidal stresses different exoplanets experience during their orbits. The known parameters are usually mass $M$, radius $R$, eccentricity $e$, orbital period $T$, and semi-major ...
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### Why circularization of an orbit has longer time scale than tidal locking?

I'm trying to understand the basic physics of orbital evolution. I know that in a two-body system (a planet orbiting a sun for example), eccentric orbits become circular, and the spin of the planet ...
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### could we use tidal forces H.E.P for energy on ceres asteroid [closed]

to make energy could we use the tidal forces in the water under Ceres surface?
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### Is there an official recommended expression for Doodson arguments?

I am following chapter 6 of this 2010 IERS note describing the calculation of a geopotential model. In the notes of equation 6.8, two expressions for the parameter called $\theta_f$ is given. One of ...
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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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### 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 there are 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. ...