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Comment by ChuckMcM | Hacker News Reader

I found this a very interesting paper. But given, 722 impacts over 7 years with a median sized 25 meter diameter crater, that is about 490 m^2 getting hit every 11 days. If such impacts were perfectly randomly distributed that is like 20K years before you have hit everywhere on the planet. You still have a much better shot at getting hit by an natural disaster that destroys your Earth base than this.

That said, it does mean you should keep watch for incoming impacts. Even a couple of kilograms of Chondrite coming in at 27,000 miles an hour is going to leave a mark on your fancy moon base. Subterranean safe rooms and auto sealing atmosphere preservation doors are going to be required equipment.

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Given that the moon is tidally locked to the Earth, all you need to do is put the base on the near side of the moon and you'll dramatically reduce the chance of being hit by a meteor.

Compare the far side [1] to the near side [2].

[1] https://en.wikipedia.org/wiki/Far_side_of_the_Moon#/media/Fi... [2] https://en.wikipedia.org/wiki/Near_side_of_the_Moon#/media/F...

Earth being 'in the way' causing fewer meteor strikes doesnt account for the differences between the near and far sides of the moon [1]. It's a fairly small effect apparently.

Of course, any moon base would probably be on the near side anyways to communicate with earth.

[1] https://medium.com/starts-with-a-bang/the-two-faces-of-the-m...

> dramatically reduce the chance of being hit by a meteor.

As seen from the moon the Earth is only 2 degrees across - that leaves the other 178 degrees wide open for hits.

I doubt it makes much difference to the hit rate - and certainly not "dramatically reduce".

Even though earth's direct shielding is only 2 degrees, its gravitational pull will deflect meteorites coming towards the moon from a far wider angle

I thought of that, but Earth's gravitation pull will also deflect meteors toward the Moon.

Averaged over the entire sky it's a null effect.

Is the distribution truly random as the article states? For instance, aren't the poles bit more safe?

Mostly random. The poles would have less direct hits, but equal number of sideways hits. Mainly because I think most meteors orbit in the same plane as the solar system. So there would be less "from above" hits on the poles.

The article addresses this:

> Meteorites can churn up the lunar surface in several ways. Along with the fresh craters, Speyerer's team found more than 47,000 ‘splotches’, formed when material gets kicked up by the main impact and rains down — sometimes tens of kilometres away.

> And that means a bigger risk for any future lunar habitats, says Stephanie Werner, a planetary geologist at the University of Oslo. The chances of a lunar base being nailed by a direct meteorite hit are relatively small, but the splattered material could pose a hazard.

>Even a couple of kilograms of Chondrite coming in at 27,000 miles an hour is going to leave a mark on your fancy moon base.

simple space/Moon version of anti ballistic missile defense system like Patriot/Aegis/S-400 should take care of it. Especially if armed with small nuclear warhead, there are still a lot of them lying around without any use.

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