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sintegral t1_j1dizsn wrote

At a far enough relative distance, the Earth and moon DO act as one large mass. You will have to be a little more specific with your second question. What specific means of energy farming from this system are you proposing if any?

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AcidNewports t1_j1dj1j0 wrote

would it show as two gravitational points with nill in the middle, interesting question?

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DemSkilzDudes t1_j1dj8r4 wrote

The moon is a useable source of energy, it's called tidal

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ExtonGuy t1_j1dmez8 wrote

No, the gravity would not act as one large mass. Imagine a rope made from one thin strand of spider silk … there would no effect at all. However, from a large enough distance, the Earth-Moon system appears pretty much like one gravitational point. At about 100 times the Earth to moon distance.

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daikatana t1_j1dn4ky wrote

Nothing acts as one large mass, not even the Earth or the moon individually. In Newtonian physics they're seen as masses at single points because at a certain distance that's close enough to what they act like and it makes the math easy, but nothing in reality actually acts like that. If you tied the Earth and moon together then nothing would change, they would act like they do now.

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ExtonGuy t1_j1dnh90 wrote

The moon’s motion away from the Earth is not a constant rate. Every month, the moon gets closer by about 13,000 miles, then it gets further away by about 13,000 miles. On average, over many decades, the distance increases by about 1.5 inches per year.

But that 1.5 inches doesn’t matter for getting energy from the moon. The moon going around the Earth is what cause tides, and we can and do get energy from tides.

https://education.nationalgeographic.org/resource/tidal-energy

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its-octopeople t1_j1dsfl1 wrote

The earth rotates once every 24 hrs, whilst the moon takes about 28 days to make a full circle. Your rope would wrap around the earth until it snapped.

If you let the earth end just dangle freely, it would move a little slower than the rotational speed of the earth 465m/s (1040mph or Mach 1.5), and alternate between dragging along the ground and being hoisted up into space, as the Moon moved in its orbit from perigee to apogee

If this was feasible (it isn't), you could grab the cable when the Moon is at it's closest, then hold on and let it pull you into space. Timed right, you'd get a maximum altitude of 42,200km, which is enough to get to geostationary orbit and then some

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its-octopeople t1_j1dtm62 wrote

There is a point between earth and moon with no net gravity. It's one of the Lagrange points (L1 I think). In this scenario, the bit of rope exactly at L1 would be under tension from the weight of rope extending to the moon on one end, and the greater weight of rope extending to earth on the other end.

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technicolordreams t1_j1dxspr wrote

The Moon and the Earth do act as one mass if you zoom out enough but every person has their own minuscule gravitational force as well. Even the ISS is attracting the earth toward it. Beyond that, that massive rope you’re using will have its own gravitational force that, if not created from resources on the moon or earth would introduce its own gravitational forces. As far as the energy you’d gain fro. The moon moving away from us, yes theoretically, you could harvest energy from it. At that point however, you’d already have build. System that re-orients the rope to the moons position relative to earth and if you have a track/system set up to accomplish that Herculean task (think The Line x a billion) you could just use that orbital motion to create as much energy as you need. It would be cheaper and probably more efficient to just build structures that harvest the current tidal energy the moon produces in the oceans. Hell, I’m sure you could build some giant canal and put a hydro-electric damn in the middle that creates power both ways. That would solve for your rising oceans problem a bit too. Alas, even these tiny versions of ideas are still multi-trillion dollar projects that no country, if not the entire worlds economy, could afford.

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space-ModTeam t1_j1e6asi wrote

Hello u/poor_kid_boon, your submission "gravitational pull" has been removed from r/space because:

  • Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

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Double_Trust6266 t1_j1e6jo7 wrote

The sun, the planets, moons and comets around each of the planets all act as one, as we move through the universe. Moon has tidal effects on planet earth. The Sun provides life, solar and invisible rays to planet earth.

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