6 ms·

The friction of the tidal forces would generate enourmous amonts of heat, and that energy would be taken from the rotation of the earth and moon, causing both t

The friction of the tidal forces would generate enourmous amonts of heat, and that energy would be taken from the rotation of the earth and moon, causing both the moon and earth to be locked into synchronous rotation. At least if the moon did not fall down on earth as it probbaly would if going this low. This would cause the moon to stay in a fixed spot in the sky. Since the area under the moon would be in shadow from it most or all of the time, this would be an extra region with polar climate, that could bind up large portion of the earths water as ice, making the earth a lot dryer elsewhere. That is provided that the water did not boil away in the process of locking the rotation.

iliis 12y ago
For a real example see Pluto and its largest moon Charon. And as you probably already know, our moon IS tidally locked to us ;) Then, there's the question "What if the earth was a torus?": http://www.aleph.se/andart/archives/2014/02/torusearth.html http://www.aleph.se/andart/archives/2014/02/torusearth.html
- Crito 12y ago
  The Moon is tidally locked to us, be we are not locked to it. Because the Earth rotates faster than the Moon orbits, tidal interaction between the two trades Earth's rate for the Moon's orbital velocity. The Earth is slowing down (and if this process continued long enough, would become tidally locked to the Moon) while the Moon is getting further and further away. If the Moon were in LEO this process would be reversed; the Moon would be spinning up the Earth while losing orbital velocity.
  - ars 12y ago
    > If the Moon were in LEO this process would be reversed; the Moon would be spinning up the Earth while losing orbital velocity. The situation is not reversible like that. Angular momentum is linear, but energy is to the power of two. So there is more energy than momentum here. You loose energy from fictional heating on the tides and energy as the rotation of the earth "pushes" the moon away. But if you reverse it than as the moon slows down, it goes lower, but as it does so it orbits even faster than before, meaning it would have to speed up the Earth even more. So rather than having extra energy (i.e. heat) you don't have enough, so instead of tidally locking to the Earth, the moon just gets faster and faster and then crashes.
    - Retric 12y ago
      Your forgetting about gravitational potential energy. Lower orbits involve less total energy.
      - ars 12y ago
        I'm not forgetting that at all. The moon can't move up or down without transferring momentum to the earth. But the amount of momentum transferred and the amount of energy transferred don't match. The difference is expressed as heat in the tides on Earth. So in one direction there is extra energy, in the other insufficient energy.
        Retric 12y ago
        Conservation of momentum is why the moons orbit increases as the earth slows down dispite taking more energy. If your speeding up the earths rotation you get energy from the lower orbit and angular momentum from the same place. Though to be really accurate you need to talk about the center of mass of the earth moon system ect.
Someone 12y ago
Given that that new polar region would get way less sun than either of the existing poles, the icebergs below it might grow a lot higher than they do at the (ant)arctic. Of course, there are way too many unknowns here. Icebergs will collapse under their own weight at some height, but gravity from the moon would somewhat counteract that. I also wonder what weather patterns would look like, whether stalactites could form on the moon, etc. Maybe, we could get ice to connect earth and moon before the moon fell down to earth.
- marvin 12y ago
  If there's any climate scientist dropouts here, it would be really cool if they did a project on this.

iliis 12y ago

For a real example see Pluto and its largest moon Charon. And as you probably already know, our moon IS tidally locked to us ;) Then, there's the question "What if the earth was a torus?": http://www.aleph.se/andart/archives/2014/02/torusearth.html http://www.aleph.se/andart/archives/2014/02/torusearth.html

Crito 12y ago
The Moon is tidally locked to us, be we are not locked to it. Because the Earth rotates faster than the Moon orbits, tidal interaction between the two trades Earth's rate for the Moon's orbital velocity. The Earth is slowing down (and if this process continued long enough, would become tidally locked to the Moon) while the Moon is getting further and further away. If the Moon were in LEO this process would be reversed; the Moon would be spinning up the Earth while losing orbital velocity.
- ars 12y ago
  > If the Moon were in LEO this process would be reversed; the Moon would be spinning up the Earth while losing orbital velocity. The situation is not reversible like that. Angular momentum is linear, but energy is to the power of two. So there is more energy than momentum here. You loose energy from fictional heating on the tides and energy as the rotation of the earth "pushes" the moon away. But if you reverse it than as the moon slows down, it goes lower, but as it does so it orbits even faster than before, meaning it would have to speed up the Earth even more. So rather than having extra energy (i.e. heat) you don't have enough, so instead of tidally locking to the Earth, the moon just gets faster and faster and then crashes.
  - Retric 12y ago
    Your forgetting about gravitational potential energy. Lower orbits involve less total energy.
    - ars 12y ago
      I'm not forgetting that at all. The moon can't move up or down without transferring momentum to the earth. But the amount of momentum transferred and the amount of energy transferred don't match. The difference is expressed as heat in the tides on Earth. So in one direction there is extra energy, in the other insufficient energy.
      - Retric 12y ago
        Conservation of momentum is why the moons orbit increases as the earth slows down dispite taking more energy. If your speeding up the earths rotation you get energy from the lower orbit and angular momentum from the same place. Though to be really accurate you need to talk about the center of mass of the earth moon system ect.

Someone 12y ago

Given that that new polar region would get way less sun than either of the existing poles, the icebergs below it might grow a lot higher than they do at the (ant)arctic. Of course, there are way too many unknowns here. Icebergs will collapse under their own weight at some height, but gravity from the moon would somewhat counteract that. I also wonder what weather patterns would look like, whether stalactites could form on the moon, etc. Maybe, we could get ice to connect earth and moon before the moon fell down to earth.

marvin 12y ago
If there's any climate scientist dropouts here, it would be really cool if they did a project on this.