If someone asks if you can move a big boulder, and the answer is that it is too heavy, it really matters if it is in a location where it can roll down, like on the side of a mountain. In that case, heavy may not be such a problem.<p>It so happens that for every elliptical orbit, there is a circular orbit with the same angular momentum but a lower energy. The amount of energy excess available from this orbital change is 0.5mv^2*(eccentricity)^2. The moon's orbit has an eccentricity of 0.055, so 0.055^2 or 0.3% of the moons orbital energy could be extracted when changing its orbit from elliptical to circular. That is about 1.1e26 J, more than 1000 times the energy from burning all fossil fuel reserves.<p>The orbital energy could be gathered by sending a swarm of satellites connected by long cables into a circular orbit around the Earth, matching the period and phase of the Moon. The satellites would be spun around a common axis, like a Klemperer rosette, but using cables instead of gravity to keep them in place. The moon would then pass through the middle of this ring twice each month. Each time it did, the moon's gravity would pull the satellites closer to the center, and the cables would be reeled in. When the moon passed by, the cables would be reeled out again to their original position, allowing for generators to gather the energy. Gathered energy could be used to put more or heavier satellites into place using mass from the moon, making the process rate increase exponentially.<p>It may not alter the moon's orbit 'significantly', but it is doable with our current state of technology.
Fun thought experiment. If you haven't read Seveneves[1], the book details what happens when the moon inexplicably explodes (spoiler alert, it's not pretty). It's a crazy Neal Stephenson novel, and I highly recommend it. Allegedly they'll make it into a movie, but I don't see how. It's too out there.<p>[1] <a href="https://en.wikipedia.org/wiki/Seveneves" rel="nofollow">https://en.wikipedia.org/wiki/Seveneves</a>
I watched an awful movie the other day where the Moon's orbit changes and they want to move it back, and I wondered the same thing. I guess the answer is no.<p><a href="https://en.wikipedia.org/wiki/Moonfall_(film)" rel="nofollow">https://en.wikipedia.org/wiki/Moonfall_(film)</a><p>(don't watch this film, it's not even so bad it's good)
There exists good explanation. Moon kinetic energy is ~10^28 J. As stated in wikipedia, Sun Luminosity ~10^26 W.<p>So to stop Moon, humanity should convert all Luminosity of Sun to force with 100% conversion rate for just 100 seconds, or just 1% for 3 hours (~10000 seconds).<p>For comparison, whole humanity annual power consumption is about 580 000 000 * 10^10 J or 5.8*10^18 J, or about 10^13 W, so to achieve 1% of Sun luminosity per second, need about 10^6 seconds, or about 10 years.<p>So in other words, if humanity will spend all consumed energy to stop Moon, will need about 10^10 seconds, or 10 000 years.<p>Sure, alter orbit about 1% seem significant enough, this will be just 100 years at full power.
If you like absurd questions like this with real scientific responses, you might enjoy the “What If?” books [1] by Randall Munroe (creator of xkcd).<p>They are full of questions like this, often with a humorous spin. Entertaining and educational.<p>Some sample questions from the Amazon description:<p>- What if you tried to hit a baseball pitched at 90 percent the speed of light?<p>- How fast can you hit a speed bump while driving and live?<p>- If there was a robot apocalypse, how long would humanity last?<p>[1] <a href="https://en.m.wikipedia.org/wiki/What_If%3F_(book)" rel="nofollow">https://en.m.wikipedia.org/wiki/What_If%3F_(book)</a>
Only somewhat related and much less serious, but hopefully humorous: <a href="https://www.youtube.com/watch?v=GTJ3LIA5LmA" rel="nofollow">https://www.youtube.com/watch?v=GTJ3LIA5LmA</a>