How Do We Keep The Moon From Eating The World?
In 2053 a manned mission to the moon, using seismic sensors, discovers that it is not a natural satellite*. The moon is actually an egg of Vespula ludicrousmegagiganto. Note that the name is not truly scientific - the shape of the creature is just vaguely wasp-like, and it stuck.
By 2071 and after extensive study, the scientific consensus is that - at some point between one and ten thousand years from now - the "egg" will hatch, and the creature will devour the earth to start its next phase of life. For obvious reasons we'd prefer this not to happen.
Is it possible to move the moon elsewhere using modern technology?
Since the science is imprecise, political will exists to start it moving ASAP, using all of the world's available resources. It could theoretically hatch at any time. They are looking to accomplish this with 2071 tech - consider this equivalent to what we have in 2015, perhaps with some optimizations but without any truly groundbreaking physics advancements. So no generated gravity or reactionless drives, for example.
Success is defined as "Put the moon into orbit around another planet within 500 years". Destroying it is officially considered too risky, although conspiracy theorists point out the tremendous scientific advances that could be gathered by studying the creature.
Ideally the movement would be accomplished without excessive impacts to the moon, but if that's not viable they will consider explosive drives.
*a competing theory is that it was a natural satellite, and the creature burrowed in and grew there over time. The difference is largely academic at this point.
This post was sourced from https://worldbuilding.stackexchange.com/q/27082. It is licensed under CC BY-SA 3.0.
1 answer
Let's do a bit of math.
According to Wikipedia, the mass of the moon is $7.3\cdot10^{22}\,\rm kg$ and its average orbital speed is $1.0\,\rm km/s$. That means its kinetic energy is $3.7\cdot 10^{28}\,\rm J$. According to the virial theorem the potential energy is $-2$ times the kinetic energy. To get the moon away of the earth (that is at potential energy $0$), you therefore need to add at least the same amount of energy as the moon's kinetic energy again.
So we are looking at a method to add $3.7\cdot 10^{28}\,\rm J$ to the moon. For comparison, the largest nuclear bomb, the Tsar Bomba, releases an energy of up to about $240\,\mathrm{PJ} = 2.4\cdot 10^{17} J$. That is, you would have to detonate about $1.5\cdot 10^{11}$ Tsar Bombas to get the energy; that's 150 billion bombs. Even at the height of the cold war, there had "only" been 68 000 nuclear weapons. So you are looking at an arsenal two million times the total arsenal of the cold war. And that's assuming you manage to transfer 100% of the energy the bombs release to the moon, which itself is rather unrealistic.
Another bit of trivia: A year has about 30 million seconds, therefore 500 years have about 15 billion seconds. So you'd have to build ten Tsar Bombas per second.
Or in short: Forget moving the moon. Better think of ways to kill the wasp.
0 comment threads
0 comment threads