Questions tagged [tidal-locking]

Questions regarding a phenomenon when an object has an orbital period that is equal to its rotational period due to gravitational tidal forces.

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4 votes
1 answer
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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 ...
2 votes
1 answer
91 views

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 ...
2 votes
1 answer
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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 ...
5 votes
5 answers
10k views

How is Mercury tidally locked if the ratio is not 1:1?

The ratio for a planet to be tidally locked has to be 1:1, but the ratio for Mercury is 3:2. How is Mercury tidally locked if the ratio is not 1:1?
5 votes
1 answer
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If the Earth became tidally locked with the moon, would that last forever?

If the Earth and the moon became tidally locked, would this last theoretically forever (assuming no external gravitational force modifies their orbits, for example, ignoring the effects caused by the ...
5 votes
1 answer
64 views

Is an extreme precession on a tidally locked planet possible?

Let's assume an exoplanet orbits a red dwarf star closely enough that is tidally locked to it. Is it possible for the planet to have a significant axial precession? If not naturally, is it possible to ...
-1 votes
1 answer
166 views

Phobos and Deimos tidal locked?

Are Phobos and Deimos tidally locked to Mars?
6 votes
2 answers
131 views

Could a tidally locked large moon prevent a close-orbiting planet from getting tidally locked to its star?

A planet can get tidally locked to its moon, like Pluto and Charon, or like Earth someday and Luna. A planet can get tidally locked to its sun - close orbiting exoplanets are assumed to be tidally ...
4 votes
1 answer
96 views

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 ...
25 votes
2 answers
3k views

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 ...
4 votes
1 answer
149 views

Is it possible to have a positive rational number of months (more than 1) in a year?

It is possible for a planet to have orbital resonance with a sun (e.g. Mercury has a 3:2 spin resonance with the sun). It is also possible for a moon to have orbital resonance with a planet (e.g. our ...
1 vote
1 answer
116 views

Will Mercury ever become locked to the Sun?

The Mercury year is between 1 and 2 days. Has it ever been greater, and will it eventually become "tidally locked" with the Sun?
2 votes
0 answers
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Would tidally locked Earth-like exoplanets necessarily have hot pole/cold pole atmospheric circulation?

A tidally locked planet orbiting a red dwarf star in its habitable zone would have a rotational period equal to its orbital period, on the order of days or weeks. Given a thick enough atmosphere ...
2 votes
1 answer
99 views

Jupiter's effect on a hypothetical "warm" Europa's water

Imagine for a moment that Europa is not frozen solid (at least on the surface). Would the fact that it is tidally locked to Jupiter mean that the water would be stagnate? So there would be no tides ...
3 votes
1 answer
218 views

Moon's rotation and revolution

Since the moon's period of rotation around its own axis, and that of its revolution around earth is (almost) same, we always see only one side of moon. This is what was, & is taught in schools. ...
3 votes
2 answers
128 views

How close to a host star can a tidally locked planet be and its dark side still maintain a moderate temperature?

So, imagine an atmosphere-less planet, tidally locked to a sun-like star. How close to the star can the planet be before its dark side becomes too hot? I imagine that at some point the rocks on its ...
4 votes
1 answer
139 views

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 ...
3 votes
0 answers
50 views

If all the Trappist-1 planets are tidally locked, which ones may have temperate zones?

Since all the Trappist-1 planets have circular orbits, it is entirely likely that all them are tidally locked. If so, which ones of the planets may have temperate zones either on the bright or dark ...
5 votes
1 answer
346 views

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 ...
12 votes
1 answer
253 views

Has the Earth-facing side of the Moon that we see today always faced us ever since the Moon got tidally locked? Or does it precess?

Title. Does the Earth-facing side of the Moon slowly precess due to perturbations and torques exerted by other bodies? Or is the side of the Moon we see today the same as when it first got tidally ...
7 votes
1 answer
2k views

Why isn't Earth tidally locked to the sun?

Given that the moon has long been tidally locked with the Earth, why isn't Earth (or any of our other solar system's planets) tidally locked to the sun?
12 votes
4 answers
9k views

Is the moon "perfectly" tidally locked and, if not, how long would it take us to observe it's rotation?

I have a general understanding of how and why a body in space can be tidally locked to it's planet or sun and I'm aware that our moon is in such a state. My question is, if our moon once had a ...
4 votes
0 answers
92 views

Are there any bodies in the solar system whose rotation is almost tidally locked or barely tidally locked?

The Moon's rotation is firmly tidally locked to the Earth and the Earth's rotation is firmly tidally unlocked with respect to the Moon. I gather that Mercury's rotation is tidally locked in a 3:2 ...
4 votes
1 answer
295 views

Can tidally locked planets have liquid oceans on their night side, and would such a planet be habitable?

Let's say we have a tidally locked planet orbiting a star. And let's say that the conditions on its surface are just right for water to exist on its surface. Conventional wisdom says that the water on ...
2 votes
2 answers
160 views

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 ...
2 votes
1 answer
125 views

Does tidal locking also slowly reduce the orbiting body's axial angle?

The Moon is tidally locked to the Earth, and it has an axial angle of 6.687 degrees relative to its orbital plane. I'd like to know: did the Moon start out with a higher axial angle? In other words, ...
5 votes
1 answer
178 views

Is there any planet or satellite in the solar system in the process of getting tidally locked?

According to Tidal locking The effect arises between two bodies when their gravitational interaction slows a body's rotation until it becomes tidally locked. Over many millions of years, the ...
3 votes
1 answer
87 views

How would a retrograde satellite experiencing tidal deceleration affect the rotation of the primary?

There are two common scenarios like this one, where an orbiting body orbits its primary slower than the primary rotates, resulting in the orbiting body moving away and the primary experiencing a ...
1 vote
1 answer
114 views

The drift of the Moon's equatorial rotation velocity

Are there any citation or documentation showing the measured degradation of the Moon's equatorial rotation velocity (thus affecting its moon's axial rotation)? I am looking for the drift of the Moon'...
2 votes
0 answers
52 views

Do retrograde spin-orbit resonances exist?

The end state of rotation of an initially fast-spinning prograde terrestrial planet (in the absence of additional forcings such as "thermal tides" in an atmosphere, e.g. Venus) is a spin-...
2 votes
0 answers
160 views

Where did the idea that tidally-locked planets have a big hurricane come from?

I've been noticing a bit of a trend in the depiction of tidally-locked habitable planets, where they are shown having a huge hurricane-like storm over the daylight hemisphere. Here's an example, and ...
4 votes
0 answers
91 views

How much (more or less) of the moon will be visible as it recedes from the Earth?

The Moon is receding from the Earth, at a rate of about 4 cm per year. We can currently see about 59% of the Moon's surface, from the Earth's surface. Will the amount of the Moon's surface we can see ...
14 votes
2 answers
2k views

Shouldn't tidal locking be impossible for a satellite that has a considerably eccentric orbit?

This popped up into my mind just now. The Moon is tidally locked to Earth, and also has a significantly eccentric orbit. This means that its orbital velocity near periapsis is considerably faster than ...
2 votes
2 answers
370 views

How can the Earth and the Moon be in synchronous rotation if the Moon won't be in geostationary orbit?

It is said that the Moon moves away from Earth and that during the Sun's red giant or white dwarf phase the Moon will be about 40% farther than now and in a synchronous rotation ("hantle rotation&...
2 votes
0 answers
56 views

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 ...
2 votes
1 answer
181 views

As the Moon and the Earth are predicted to get into tidal lock, how slow would the Earth rotate?

This answer to Will the Earth ever be tidally locked to the Moon? supports the widely held thinking that during the Sun's red giant phase or later the Earth and the Moon should be tidally locked to ...
8 votes
1 answer
646 views

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 ...
5 votes
1 answer
133 views

Could iron rain upset tidally locked WASP76b?

The Jupiter mass planet WASP76b orbits its 1.5*Sunmass star at 0.03AU and is tidally locked. The day side heats to 2400C which vaporizes metals, including iron observed in its atmosphere. The balmy ...
2 votes
0 answers
17 views

Could iron rain upset tidally locked WASP76b? [duplicate]

The Jupiter mass planet WASP76b orbits its 1.5*Sunmass star at 0.03AU and is tidally locked. The day side heats to 2400C which vaporizes metals, including iron observed in its atmosphere. The balmy ...
3 votes
1 answer
149 views

Temperature of a substellar point on an airless tidally-locked planet

If a hypothetical blackbody planet's components were solid at all temperatures, would the substellar point on the airless tidally-locked (1:1) planet eventually heat up to the surface temperature of ...
4 votes
1 answer
141 views

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 ...
7 votes
4 answers
742 views

Is there any residual oscillation left from the Moon rotation?

The Moon is tidally locked to Earth - a long time ago it was spinning, but after a time, the spin stopped - two factors stabilizing it: unequal mass distribution creating an equilibrium position where ...
3 votes
1 answer
636 views

Requirements for a satellite/planet to be tidally locked to a planet/star

The Moon is tidally locked to the Earth, the Four Galilean are tidally locked as well, and the recently found planetary sistem TRAPPIST-1 has seven tidally locked planets, but Venus or Mercury are not....
1 vote
1 answer
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tidaly locked celestial body in three planet system

If a Planet have 2 Moons (so suppose system of 3 bodies) and we say "One Moon is tidally locked to Planet" how can we say that it is tidally locked when Baricenter of 3 bodies has its trajectory?
6 votes
2 answers
746 views

Lunar phases if Earth was tidally locked to the Moon

I know that the Earth will never become tidally locked to the Moon, so this is purely hypothetical. If I understand correctly, in this hypothetical scenario an Earth day is now a lot longer at ...
3 votes
1 answer
244 views

Tidally locked, and yet spinning?

Reading about Uranus almost 90° tilt, I was wondering if some rocky planet with mass concentration at one pole could possibly spin around its own axis, while still being locked to its star? Which ...
2 votes
1 answer
74 views

Earth rising and setting from moon's perspective

Why the earth is rising and setting seen from the moon, when the moon is tidally locked? Shouldn't the earth be always on the same spot because of the tidal lock, if observed from the moon?
5 votes
0 answers
124 views

Does the orbital decay of Triton affect Neptune's rotation?

Just a quick question regarding Neptune. Because Phobos is spiraling in towards Mars, Mars' rotation speeds up. Does the same thing happen with Neptune's rotation?
4 votes
1 answer
147 views

How big does the moon have to be to have the Earth tidally locked to it

I would like a earth-moon system like Pluto-Charon (but with earth instead of Pluto) where both will be tidally locked to each other within something like a billion years. As the moon would probably ...
4 votes
3 answers
2k views

Is the moon's revolution speed increasing or decreasing

I've come across multiple answers to this question. So, the moon is moving away from the Earth a couple of centimeters per year and the Earth's rotation is slowing down. Here it says the moon's ...