An odd question on orbital dynamics

In summary, the conversation discusses the possibility of a celestial event causing the Earth's rotation to become tidally locked to the sun. It is mentioned that this could happen naturally over a long period of time, but could also potentially be caused by the passage or orbit of a large gravitational body. However, it is determined that such an event would require a significant amount of mass and would likely not occur within a short timescale. The idea of using multiple flybys to achieve this is also discussed, but it is noted that this would be difficult to achieve and could potentially have other negative effects on the Earth's orbit.
  • #1
parsec
113
1
Is there any kind of celestial event that could occur that could completely lock the Earth's rotation such that it is constantly facing the sun, in the same way the moon is tidally locked to the earth?

What would it take? Could it be caused by the passage or entrance of a new gravitational body into the solar system?
 
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  • #2
Yes. It's called time. Give it a few tens or hundreds of billion years, and it will happen on its own.
 
  • #3
The Earth will fall into the (expanding) sun long before that would happen.
Impacts of asteroids, fly-bys of very massive objects or stuff launched into space can modify the rotation of earth. You need a lot of mass for any significant change, however.
 
  • #4
Okay, let me rephrase.

Is there any mass, position, linear and rotational velocity configuration of a foreign planet or body entering the solar system that could reduce that timescale for the Earth's tidal locking to something in the order of days, weeks or months?

Sorry if this is an absurd question, I don't know much about this sort of thing.
 
  • #5
Is it possible without impact?
 
  • #6
mfb said:
fly-bys of very massive objects

Ah yes, this sort of thing. I wouldn't know where to begin calculating what kind of regime is plausible, but I'm guessing the nearby passage of a planet with mass greater than the Earth could cause such a dramatic perturbation of the Earth's rotation?

Would the more distant passage of a star be equally plausible?
 
  • #7
parsec said:
Is there any mass, position, linear and rotational velocity configuration of a foreign planet or body entering the solar system that could reduce that timescale for the Earth's tidal locking to something in the order of days, weeks or months?
No. Not without ripping Earth apart. You would need many fly-bys or a very close orbit (which is tricky to achieve with a massive object) - in any case, I think the timescale would be at least millenia or more, but I did not check the numbers. It would produce serious, probably periodic floods everywhere apart from some mountains and increase volcano activity a lot.

More distance and more mass can increase the timescale of the influence a bit, but if the numbers get too large you ruin the orbit of Earth as well (long before you see a slowed rotation).
 
  • #8
It can't be done with a flyby. You need a net torque with no net force.
 
  • #9
A flyby would induce tides, which give a torque (similar to the earth/moon system). You get a net force and change the orbit, too, of course. As you need multiple flybys, those could cancel in the long run. Not very realistic, but it might be possible to do that in a planned way.
 
  • #10
Maybe I should have said "you can't do it with one flyby".

The most realistic way to handle multiple flybys is an orbit.
 

1. What is orbital dynamics and why is it important?

Orbital dynamics is the study of the motion of objects in orbit around a central body, such as planets, moons, and artificial satellites. It is important because it allows us to understand and predict the movement of these objects, which is crucial for space exploration, satellite operations, and understanding the behavior of our solar system.

2. How does gravity affect orbital dynamics?

Gravity is the force that governs orbital dynamics. It holds objects in orbit around a central body and determines the shape, size, and speed of their orbits. Objects in orbit are constantly falling towards the central body due to gravity, but their forward motion keeps them in a stable orbit instead of crashing into the body.

3. What factors affect an object's orbit?

The factors that affect an object's orbit include the mass of the central body, the object's mass, the distance between the two objects, and the velocity of the object. These factors determine the strength of the gravitational force and the shape, size, and stability of the orbit.

4. How do scientists calculate orbital trajectories?

Scientists use mathematical equations, such as Kepler's laws of planetary motion and Newton's law of universal gravitation, to calculate orbital trajectories. These equations take into account the various factors that affect an object's orbit and allow scientists to make accurate predictions about the object's movement.

5. Can orbital dynamics be applied to other systems besides our solar system?

Yes, orbital dynamics can be applied to any system in which objects are in orbit around a central body. This includes binary star systems, galaxies, and even artificial systems like satellites in Earth's orbit. The same principles of gravity and motion apply, making orbital dynamics a universal concept in understanding the movement of objects in space.

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