This question came to me after reading this question on the Astronomy Page, and having a length discussion with colleagues about the 2002 movie "The Time Machine". As a result I am looking for hard-science based hypotheses about what would happen.

Setting the Background

Let's assume we as humanity, somehow damaged the moon such that it split in two (See Edit 2). This would obviously have immediate effects on our lovely blue ball we call home. What I imagine those effects would be are a drastic change in the tides, which would result in a change in weather patterns, probable large scale earthquakes as the earth and moon work out their differences and settle out a new orbit. There would probably be meteors (moon-debris) crashing through our atmosphere as well. There is probably more, but I don't know enough about geology, and what not to come up with more.

In all honesty - I am using the imagery in my mind for this accident as shown in the below picture. This is taken from The Time Machine, and occurs the day "their" moon was split.enter image description here

If you come up with more please note it in your answer.


Let's fast forward 500 years. What does our world, our society(ies) look like. Would we as a people advanced or would we have regressed and enter a new "Dark Ages" in terms of society and lifestyle? Here is the kicker - what would be the biggest changes we as humanity would face and how do you believe we could overcome them? Please use science to back up your hypothesis of how the lunar changes would effect us, and how these changes would impact, shape or destroy society.

enter image description here


It's been pointed out to me that this may be a duplicate of this question. And while, they both deal with the shattering of the moon and the effects of it on the planet. That post doesn't deal with the human aspect of it, which my question does.

Edit 2 --- How the moon was split

The year was 2049, the moon had successfully been settled with a small International group and they were researching the surface and doing minor core drilling for samples. As we discovered during the Apollo Moon Landing and since, there are a lot of moonquakes. One day, it was relatively routine, there was an asteroid impact on a portion of the moon far enough away that our settlement was left intact. However, the subsequent moonquake which was compounded by our core drilling and the new(ish) fixtures of our settlement on the planet sparked a chain reaction that resulted in the splitting of the moon - much like a windshield after getting a rock chip.

Yes, I realize that this cause is far fetched, but I wanted to go with something that would generally keep the moon in its orbit so we can focus on the human aspect of life on earth post-split.

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    $\begingroup$ Unless Moon is deliberately split in a manner that minimizes impact on Earth, amount of debris falling down to Earth would greatly exceed the Chicxulub asteroid. Thus it is very likely that human civilization as we know it would cease to exist. What (when and if) would come after that would greatly depend on the amount of damage that Earth had sustained. $\endgroup$
    – Alexander
    Aug 15, 2019 at 21:51
  • $\begingroup$ I read that, question worldbuilding.stackexchange.com/questions/29231/… however I am more concerned about society than the planet. I am assuming it doesn't slam the moon into the planet (hence the pictures). $\endgroup$
    – user66696
    Aug 15, 2019 at 21:55
  • $\begingroup$ To split the moon in a way that it doesn't just reform would be an insane amount of energy required. You literally have to move half the mass of the moon beyond the moon's escape velocity to make it split cleanly in two. The energy required to do that might as well be the same as moving the whole moon. Explaining what massive cataclysm could generate such energy might provide an avenue for determining the effects on the Earth. $\endgroup$
    – stix
    Aug 15, 2019 at 21:57
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    $\begingroup$ @JCrosby The how and why will definitely affect the aftermath, which is why you should define it. $\endgroup$
    – stix
    Aug 15, 2019 at 21:59
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    $\begingroup$ Neal Stephenson's Seveneves is an excellent novel exploring the consequences of shattering the Moon into pieces. The hardcover edition has 880 pages. $\endgroup$
    – AlexP
    Aug 15, 2019 at 23:26

1 Answer 1


There won't be any humans to have a society.

The single Chicxulub Impactor, which caused a mass extinction that included dinosaurs among many others, was about the size of a small city (not a big city). It's devastation was phenomenal - our estimates of a Nuclear Winter are like a day at the spa by comparison.

Shattering the moon, which is the only case that has an interesting conclusion, would likely rain hundreds of Chicxulub-sized impactors...as well as dozens of much, much larger impactors.

The first one will destroy human technological civilization and make a large section of the surface difficult to inhabit and likely non-arable. The rest of the impactors, over centuries as they slowly spiral in, will repeat the damage over and over...and over...and over. There will be no safe havens.

Food production will be disrupted repeatedly. Humans can't go very long without food, and humans cannot grow crops without seeds. Many will incinerate in the impacts, many will drown in the mega-tsunamis; most will starve.

If we go back and look at the less-interesting case, the moon cracks but does not shatter...then gravity will pull the crack closed fairy quickly.

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    $\begingroup$ I know this question has a hard-science tag. I doubt that citations beyond Wikipedia will improve any answers to this particular question. A hard-science answer might do a good job predicting the distribution of impactors (if we had an origin vector), but that's not what the OP asked. I doubt we will find anything to cite that will estimate the number of survivors (if any), and predicting their hardscrabble culture would be opinion-based. $\endgroup$
    – user535733
    Aug 16, 2019 at 2:19