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Quadruple Bypass
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if we were to tie a rope around the moon and have the end on earth. what would happen if we were to pull the moon? could we actually pull it closer until it eventually collides with earth?
That's a pretty big "if". There is no material known with the tensile strength to support it's own weight as it hangs down from the center of gravity to the respective masses of Earth and Moon. Tugging on that rope would add to the stress upon it. If you could come up with such a material and anchored it at both ends, then you could pull on it and set up a force that would tend to bring the two masses together. However, you have other problems to overcome.Quadruple Bypass said:if we were to tie a rope around the moon and have the end on earth. what would happen if we were to pull the moon? could we actually pull it closer until it eventually collides with earth?
jimmysnyder said:Perhaps you are aware that the Earth and Moon are actually receding from each other even as we speak. In order to reverse that motion and have the two approach you would need apply enough force to overcome this effect.
Yeeeessss... The other way to look at it is that, as you pull the Moon toward the Earth, you will be pulling it into a tighter orbit, it will move forward and ultimately outward again (because you will have moved it into an elliptical orbit). The Moon will act to resist your pull.jimmysnyder said:In other words, the system will start to spin like a figure skater that has pulled in their arms.
Quadruple Bypass said:well i just really wanted to know if it would be possible
The momentum is not neglible. It must be overcome before the Moon stops receding and starts to approach.DaveC426913 said:Which, at a mere 4 centimeters per year, is negligible.
The Moon's elliptical orbit alone causes its distance to change by ~40,000km every two weeks. That is a factor of ~10^13 greater than the Moon's biweekly recession of 1.6mm.jimmysnyder said:The momentum is not neglible. It must be overcome before the Moon stops receding and starts to approach.
With a slipknot, obviously.Janus said:I'm surprised that no one has brought up the question of exactly how one would anchor said rope to the Earth, considering that the Earth rotates at a much different rate than the Moon revolves around it.
Janus said:I'm surprised that no one has brought up the question of exactly how one would anchor said rope to the Earth, considering that the Earth rotates at a much different rate than the Moon revolves around it.
naw, tie it to the north pole. let it wrap around. maybe we could pull it in without a winch.DaveC426913 said:With a slipknot, obviously.
rbj said:naw, tie it to the north pole. let it wrap around. maybe we could pull it in without a winch.
rbj said:naw, tie it to the north pole. let it wrap around. maybe we could pull it in without a winch.
Janus said:Ah, but the moon's orbit doesn't lie on the equator, so its distance from the North pole would change even if it were in a circular orbit.
Janus said:I'm surprised that no one has brought up the question of exactly how one would anchor said rope to the Earth, considering that the Earth rotates at a much different rate than the Moon revolves around it.
That momentum need not be stopped, the 4 cm/yr must be.DaveC426913 said:The Moon's elliptical orbit alone causes its distance to change by ~40,000km every two weeks.
You're clutching at straws.jimmysnyder said:That momentum need not be stopped, the 4 cm/yr must be.
S'only 5 degrees.Janus said:Ah, but the moon's orbit doesn't lie on the equator, so it's distance from the North pole would change even if it were in a circular orbit.
DaveC426913 said:S'only 5 degrees.
Integral said:Whats the problem? You just anchor it some where on the equator...Yell heads... Let 'er wind up. You would pull it in at a rate of 1 Earth circumference per day. (The heads holler is to let everyone on the path of the rope know that something is comming their way!) :rofl:
You would take a short section of rope and form a yoke from North to South pole, then attach your main rope to that with a slipknot. Now the Earth can pin and wobble all it wants without slippage.Janus said:That's quite a lot of people you are going to have to warn!
Consider that the moon's orbit is tipped at 17° to the equatoral plane. The rope will tend to wind its way North or South (depending on the orientation of the orbit at the time.) Once it gets to about 17° of the pole,(Actually less, sometime before that, the tension on the rope will be greater than the friciton between the rope and the Earth.) then it will just keep slipping off. Then, as the month progresses, the moon's position will change orientation to the Earth's axial tilt. As it does so, and the Moon gets closer to the equatorial plane, the rope will work its way closer to the pole again. After the Moon crosses the equatorial plane, the rope will start to work its way back toward the equator and then eventually to the other pole. Then the process repeats in the other direction. After a while the Earth will look like a giant ball of string, with just the ice caps exposed.
The above is even a over simplfied scenerio as it ignores the torque placed on the Earth by the off center force of the rope as it works it way toward the poles.
DaveC426913 said:You would take a short section of rope and form a yoke from North to South pole, then attach your main rope to that with a slipknot. Now the Earth can pin and wobble all it wants without slippage.
Yewah, as I was writing it, I realized it was drifting from the simplest 'wind em up' arrangement proposed.Janus said:Okay, but this is different form anchoring to a point on the Equator and letting the Earth's rotatation reel in the Moon, which was what I was responding to.
If we were somehow able to pull the moon closer to Earth, the effects would be catastrophic. The moon's gravity has a significant influence on Earth's tides, so bringing it closer would cause massive tidal waves that could devastate coastal areas. Additionally, the moon's orbit helps stabilize Earth's rotation, so disrupting its position could lead to changes in our planet's tilt and potentially alter our climate.
The force needed to pull the moon closer to Earth would need to be immense. The moon has a mass of about 7.3 x 10^22 kilograms, and it is approximately 384,400 kilometers away from Earth. To overcome the moon's inertia and gravitational pull from Earth, we would need an incredibly powerful force, likely beyond our current capabilities.
Yes, pulling the moon closer to Earth would definitely affect its orbit. The moon's orbit is a delicate balance between its own gravitational pull and the gravitational pull of Earth. Moving it closer would disrupt this balance, and the moon would likely end up in a new, unstable orbit or even collide with Earth.
It is unlikely that pulling the moon closer to Earth would have any beneficial effects. As mentioned previously, it would likely cause catastrophic consequences for our planet. Additionally, the moon's current distance and position play important roles in regulating Earth's climate and maintaining a stable orbit around the sun.
In theory, it is possible to pull the moon closer to Earth using a powerful force. However, the consequences of doing so would be disastrous and far outweigh any potential benefits. It is important to also consider the ethical implications of manipulating the natural forces of our solar system for our own gain.