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I wonder how stable such tubes would be? No water erosion, no earthquakes, even though they must have formed at a time that was more geologically active. They c
by kseverest 9y ago
I wonder how stable such tubes would be? No water erosion, no earthquakes, even though they must have formed at a time that was more geologically active.
They could be on the edge of collapse if say, a large vehicle drove in them. Am I wrong?
Just a first thought. Other than that, they could probably serve as a goal for human spaceflight, an intermediate step between walking on the moon and colonizing mars.
- galaxyLogic 9y ago> no earthquakes No but how about moon-quakes? Ok, not geologically active you say. But moon's been bombarded by asteroids it's surface is full of craters. Creating a crater wouldn't that be an equivalent of a moon-quake?
- kseverest 9y agoYou are absolutely correct.
- nkoren 9y agoThis is the correct answer. These lava tubes are, at their youngest, a couple billion years old. Since then, the moon has been thwacked very hard and -- on those timescales -- often. If the tubes haven't collapsed yet, then there's a high likelihood that they're exceptionally stable.
- DougWebb 9y agoThat could be survivor bias. Maybe there used to be a lot more of them.
- robryk 9y agoWouldn't a collapsed tube be very distinctive visually?
- nkoren 9y agoVery much so -- and one has even been explored by humans! https://en.wikipedia.org/wiki/Hadley%E2%80%93Apennine https://en.wikipedia.org/wiki/Hadley%E2%80%93Apennine
- njarboe 9y agoYes survivor bias. But since these survived, they are likely to be structurally sound. Like antique furniture or structures on Earth.
- larkeith 9y agoDoes that count as natural selection?
- pstuart 9y agoI don't think lava tubes breed.
- hyperbovine 9y agoSurvival of the fittest, then.
- knappe 9y agoYou're not accounting for tidal forces. The same forces that create the tides on Earth also affect the moon. In this case via moon-quakes. https://phys.org/news/2017-08-moon-tidal-stress-responsible-deep.html https://phys.org/news/2017-08-moon-tidal-stress-responsible-...
- hyperpallium 9y agoBut the moon is one-face, so tidal stress should be constant.
- harperlee 9y agoWhat about the sun's? If the force is strong enough to make earth orbit, and moon-to-sun distance oscillates, plus seasonal behaviour, there must be quite some straining tides...
- hyperpallium 9y agooh yeah, that makes sense. It's a tiny fraction of the moon-sun distance, but it would have some efrect. Is it a "tidal" force, though?
- andai 9y agoThe sun also creates the tides.
- ballenf 9y agoThe article mentions the use of inflatable housing inside. Seems like a wise move given we have so little experience with their stability. If they've survived this long, then presumably they are very unlikely to collapse on their own. That is, settlers would only need to worry about collapse cause by their own movements. The odds of them being 'on the verge of collapse' are relatively low in my thinking. Unless there is some process that takes them to the edge and then stops that we don't understand. Otherwise, they are likely to have either already collapsed or be somewhat stable.
- QAPereo 9y agoThe moon is pretty dead, so no processes exist... if they’re stable, barring asteroid strike. They’d remain stable. The problem is metastability, the “death block” problem in ice climbing.
- millettjon 9y agoThere are moonquakes so not completely dead. https://www.nasa.gov/exploration/home/15mar_moonquakes.html https://www.nasa.gov/exploration/home/15mar_moonquakes.html
- valuearb 9y agoWouldn’t the acceleration of falling objects be slow enough that the force delivered be much lessened?
- nnfy 9y agoI'd imagine the tubes are relatively stable because they regularly (at geologic time scales) experience seismic disturbances from weak plate tectonic activity and especially impact events.