# If the distance between Earth and the moon were changed, would the effects be immediate? [closed]

I need your help on a possible (but perhaps low probability) scenario for how the distance between Earth and the moon could change: say a large object from the Kuiper Belt manages to make its way into the inner system. It passes by our moon such that its gravity changes the moon's orbit around Earth into a more pronounced ellipse. So there will be times when the moon is much closer to Earth and other times when it's further away than its current distance from Earth.

Say that this change in the moon's orbit isn't enough to cause an apocalyptic scenario for life on Earth but that the tides are of course much, much more pronounced. I surmise that the greatest impact would be felt in costal towns and cities around the world. My question is: how long would it take for the change in the moon's orbit to be felt on Earth? Are we talking almost immediately/ within the hour for some unlucky areas that are now much closer to the moon on its new orbit, and at most within 12 hours for the "luckier" areas? Or would the time frame be much longer?

Thank you in advance for any insights you could offer on this.

## closed as too broad by Pont, Communisty, bon, Fred, arkaiaOct 10 '17 at 15:39

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• I think this question is simply too broad: there are a practically infinite number of ways in which the moon's orbit can be perturbed, and the time-scale of the effects on Earth will depend on the exact nature of the perturbation. Gravitational effects propagate at light speed so in a strict physical sense Earth would be affected in 1.3 seconds, but you seem to be asking something more along the lines of "when would the effects become noticeable/significant" which (as stated) is impossible to answer in general. – Pont Oct 10 '17 at 6:41