34
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Accepted
How can Io be tidally heated while it is in tidal lock?
How can Io be tidally heated while it is in tidal lock?
It is tidally locked in a mean motion sense of "tidally locked". That Io is in an eccentric orbit rather than a circular orbit means ...
- 36.3k
27
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Shouldn't tidal locking be impossible for a satellite that has a considerably eccentric orbit?
You are right, that would be weird if the Moon speeds up and slows down this way to always show the exact same side to the Earth. That's why it doesn't.
At some point in the orbit the Moon's rotation (...
- 3,441
26
votes
Accepted
Would the Earth and Moon still have tides after the Earth tidally locks to the Moon?
There won't be significant lunar tides. The moon will become fixed at one location above the Earth. The tidal forces that drive the resonant water flows that we call "tides" will be fixed. ...
- 129k
21
votes
Under which conditions could a planet's massive moon's orbit get closer to the planet?
Yes, it is possible for a moon of a planet to move closer to the planet. If a moon moves close enough to the planet, the moon will eventually reach its Roche limit and shatter or else collide with ...
- 8,037
20
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"Tidally locked" Oort Cloud object
The question in the title and the body are different. There are no tidally locked objects in the Oort cloud. The sun's tidal forces at that distance are not sufficient to lock an object's rotation. ...
- 129k
19
votes
Will the Earth ever be tidally locked to the Moon?
As the moon orbits Earth, tidal forces slow down the Earth's rotation by 2 milliseconds per century. Eventually, in tens of billions of years, the Earth and Moon would achieve a double tidal lock, ...
- 6,360
16
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How would ocean tides work on a tidally-locked planet?
Since the tidal bulge is always in the same place, how would that affect ocean tides?
The concept of tidal bulge is a useful fiction, but fiction nonetheless. For an object in an eccentric orbit, the ...
- 36.3k
13
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How can Io be tidally heated while it is in tidal lock?
That sentence on wikipedia continues "from friction generated within Io's interior as it is pulled between Jupiter and the other Galilean moons".
There's an orbital resonance (with the other ...
- 498
12
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Effects of a binary star system on a tidally locked planet
The "three-body" problem and its stability are still an unsolved problem in general. There are papers that do long term integrations of planet orbits in binary systems to study their ...
- 162k
11
votes
Is the moon "perfectly" tidally locked and, if not, how long would it take us to observe it's rotation?
The Moon indeed "wobbles" about in its orbit because it goes around the Earth in an ellipse and not a circle. From our point of view, it wobbles a little back and forth such that over a lunar cycle, ...
- 811
11
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Accepted
Is the moon "perfectly" tidally locked and, if not, how long would it take us to observe it's rotation?
The question is interesting, but I suspect the answer is that the Moon will never show its "far side" to the Earth, because there are differences between the side that faces us and the far ...
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10
votes
Will Mercury ever become locked to the Sun?
Mercury is tidally locked; it has a 3:2 resonance with the Sun, where it rotates three times for every two orbits. It is well understood that Mercury is tidally locked, but modern explanations for how ...
- 3,404
10
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Under which conditions could a planet's massive moon's orbit get closer to the planet?
Under which conditions could a planet's massive moon's orbit get closer to the planet?
I'll give the most straightforward condition:
The tidal interaction tends to accelerate the orbiting moon in the ...
- 4,877
9
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Accepted
Is it coincident that all planets with tight orbit are tidally locked to their parent body?
This is a physical result:
The change in rotation rate necessary to tidally lock a body B to a larger body A is caused by the torque applied by A's gravity on bulges it has induced on B by tidal ...
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9
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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?
The Earth-facing side of the Moon doesn’t change currently due to any of the forces on it by other bodies (excepting librations).
From Gladman et. al.: “tidal dissipation in the satellite drives it to ...
- 16.7k
9
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"Tidally locked" Oort Cloud object
Suppose you orbit with period $P$, and have a angular velocity $\omega$ randomly chosen (let's start with everything aligned in a plane orthogonal to spin too). Then to keep your face pointed towards ...
- 15.7k
9
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Is there any evidence that the rotation period of the Moon was different to its orbital period in the past?
There is plenty of evidence for the Moon's orbital period being different in the distant past. However, there is little if any evidence that the Moon's rotation rate differed from its orbital rate.
...
- 36.3k
8
votes
Accepted
Would a tidally locked planet be always increasing in temperature?
Hot objects radiate heat. The hotter something is, the faster it radiates heat.
The side of the planet that faces the sun would heat up until the rate at which it is absorbing heat from the star is ...
- 129k
8
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Why isn't Earth tidally locked to the sun?
Really, it's just because the tidal locking timescale is so long for Earth:
$$t\propto\frac{a^6m_{s}}{m_{p}^2R_s^3}$$
where $a$ is semi-major axis, $m_s$ is the mass of the secondary object, $m_p$ is ...
- 37.4k
8
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As the Moon and the Earth are predicted to get into tidal lock, how slow would the Earth rotate?
The last part of the answer you linked to actually says (right at the end) that tidal locking will never be achieved, with reasoning similar to what I gave in this answer.
That said, even though the ...
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8
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Shouldn't tidal locking be impossible for a satellite that has a considerably eccentric orbit?
With a more eccentric orbit, tidal control of the rotation does not lead to a librating lock. Mercury is in a 3:2 spin-orbit resonance. Hyperion's spin is chaotic: it gets a quasi-random kick each ...
- 2,777
8
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Accepted
Tidally locked Venus, is it possible and consequences?
It may not be possible for Venus to become tidal locked
I don't think we know if it's possible for Venus to become tidally locked. Correia et al. 2008
expect the equilibrium rotation to differ from ...
- 16.7k
8
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Under which conditions could a planet's massive moon's orbit get closer to the planet?
Both Sten and M.A.Golding have provided good answers, so I shall only add some details.
(1) The tides exerted in the planet by the moon are pushing the moon away when its semimajor axis' exceeds the ...
- 1,552
7
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A "tidally locked" double planet?
Your scenario isn't stable. A simple way to explain this is to imagine that the planet's orbit each other at the same rate they orbit the star (your scenario has them orbiting even slower).
At the ...
- 24.2k
7
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Earth rising and setting from moon's perspective
You're quite right. The Earth is (nearly) stationary in the Moon's sky.
(I say "nearly" because the Moon is in a slightly elliptical orbit around the Earth, but rotates perfectly smoothly. This ...
- 7,690
7
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Why circularization of an orbit has longer time scale than tidal locking?
Tidal locking is a primary effect due to a direct torque on a body from its tidal bulge lagging its rotation. This is pictured nicely on wikipedia with an example from the Earth/Moon system.
Tidal ...
- 16.7k
7
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Could a tidally locked large moon prevent a close-orbiting planet from getting tidally locked to its star?
Yes, but the tidal torques will prevent the planet from being locked either to the star or moon.
Suppose the orbital paths are both prograde and coplanar and the planet obliquity is zero. Then tidal ...
- 16.7k
7
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Accepted
Is this definition of tidal locking really satisfying?
Currently, the Moon is tidally locked to the Earth but the Earth is not tidally locked to the Moon.
In your scenario (which could be accomplished by raising the mass of the Earth), where the Moon has ...
- 4,877
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Is this definition of tidal locking really satisfying?
Rather than your question (which Sten has already answered well), let me reply to one of your comments under Sten's answer, since I think that's where the core of your misunderstanding lies:
In this ...
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