Let's face it, the moon just isn't as impressively large in the sky as we want it to be. Even though we've got the biggest apparent-sized moon of any planet, we keep picturing it bigger. So let's make it bigger.
Or rather, let's have robots make the moon bigger, by digging rock out of the interior of the moon, and using that rock to build giant arched structures upward, layer upon layer.
We start by sending some robotic mining rovers up there, either solar- or atom-powered, with replication equipment. At first, we have folks control the robots from Earth---there's not much lightspeed delay, but it's going to get boring (and tunnelling (heh))--- so we add increasing autonomy as time passes.
The work begins with some of the robots tunnelling into the moon and bringing up the rock from the tunnels to the surface. The rock brought up is shaped by the construction robots into arched structures that build higher and higher, layer after layer, like multi- storied cathedrals. The lesser gravity of the moon will allow very light structures.
The interesting work, for this project, is that the tunnels reduce the density of the moon, decreasing the surface gravity, and the structures built on the surface increases its diameter, enlarging it, and further decreasing the surface gravity. Which allows even further expansion, as long as the robots keep rebuilding.
The robots don't need to stick to building with rock, of course. There's plenty of metals and other raw materials to be mined and processed into building beams and mining supports and robot parts.
Some of the robotic equipment uses the mined materials to build more robots and more robot-building machines. We could take measures to prevent them from replicating through space and taking over the Earth.
The robots constructing new surface layers can brighten the surface of the moon, by placing lighter-colored materials on top (the Moon is currently as dark as charcoal). That will brighten our nights a bit, and let more people notice the moon in the daytime. (The robots can, of course, arrange some dark materials into a sponsor's logo.)
As the building materials change, the diameter can further increase, which will allow even lighter construction. The very lightest materials now made are aerogels. The lightest structures now made are bubble/domes supported by gas pressure from inside. A stiff aerogel shell could be made gastight, and could insulate a hot gas inside it, and the moon could become a balloon.
The practical limit to the diameter of the reconstructed moon would probably be reached when the surface reached the balance point between the moon's own gravity and that of the Earth. Anything on the surface at that point could simply float away into space, which would be handy for shipping. Before that, electromagnetic launchers could be build into the tunnels and structures.
One useful shape to make from the moon converted into advanced materials would be a giant movie [TV or monitor type] screen to be seen from Earth. The shape for that would be reminiscent of the Eiffel tower standing on a plate. The flat bottom of the plate would face the Earth, with the tower pointing away, holding up enough mass to keep the structure stable through tidal lock. The [TV] screen could hold a [whole bunch of] projector [pixels] built from an array of lasers --- the robots should be told to not build lasers capable of destroying Earth. (According to my best math, the movie screen would be a little closer to Earth than the moon is now, and somewhat larger.)
Once the construction is finished, the robots could be asked to disassemble themselves for parts for other machines, or just allowed to roam the revamped moon, bored, frustrated, powerful and self-replicating, with lasers.-- baconbrain, Sep 09 2014 Lunark Lunarkit's the loony-est. [2 fries shy of a happy meal, Sep 09 2014] See 4:08 https://www.youtube...watch?v=8Tp0E_5R_Z8"A popcorn ball meteor!" "The worst kind!" [RayfordSteele, Sep 10 2014] Moon VLO device Moon_20VLO_20DeviceFun stuff here in the annos relevant to hollow celestial bodies. Including tutorials and equations [bungston, Sep 12 2014] Surface Gravity http://en.m.wikiped...iki/Surface_gravityThe mass can be considered to be concentrated at the center, and the gravity diminishes by distance. [baconbrain, Sep 13 2014] Why not just hang a large magnifying glass in front of it?-- xenzag, Sep 09 2014 Because of the robots with lasers.-- baconbrain, Sep 09 2014 <applause>
Strip mines should be required to fabricate their tailings into cathedrals-- sninctown, Sep 09 2014 "Even though we've got the biggest apparent-sized moon of any planet"
You worded that very carefully, I see. I couldn't resist checking some numbers. Io seen from Jupiter, and Triton seen from Neptune, are ALMOST as big in apparent size as Luna seen from Earth. But Charon seen from Pluto looks MUCH bigger (about 1/3 the diameter but 20 times closer). Too bad Pluto is only a "dwarf planet"....-- Vernon, Sep 09 2014 Really it is not how big it is, but what you do with it that matters. Which is why I am delighted by the prospect of a large movie screen!
But I am unclear how it would work. Projecting from Earth would be nice but you could do that with the moon now, and there are bats and clouds and things in the way. Would the tower hold the projector and project downwards? You would need the tower off to the side I would think, unless you show movies which all have a large tower in the center of every shot.-- bungston, Sep 09 2014 //the tunnels reduce the density of the moon, decreasing the surface gravity, and the structures built on the surface increases its diameter, enlarging it, and further decreasing the surface gravity. Which allows even further expansion, as long as the robots keep rebuilding.//
I suspect that this is not sufficiently true to allow infinite expansion. Nice idea though!-- MaxwellBuchanan, Sep 09 2014 [MaxwellBuchanan], ignoring everythingthing else (like that pesky gravity and such) the theoretical limit would be a spherical shell, the same mass as the moon, but only 1 atom thick. I feel some calculations approaching...-- neutrinos_shadow, Sep 09 2014 Hmm. Is such a structure stable against gravity?-- MaxwellBuchanan, Sep 09 2014 No, no. You'll ruin the eclipses.-- tatterdemalion, Sep 09 2014 The rebuilt moon could be an enormous filigree tracery of lacework arches, with a flat disc in the centre, just the size required to eclipse the sun.-- pocmloc, Sep 09 2014 Original idea [+] expressed as wall of text [-].-- the porpoise, Sep 09 2014 Sheesh! Assuming a 1-atom thick shell of otherwise lunar density, the radius of the sphere will be around 670AU. That's substantially larger than the solar system (not as far as the Oort Cloud, but much bigger than the Kuiper Belt). Any "open" lattice-worky structuring will make it even bigger! But being sensible about the thickness will make it smaller.-- neutrinos_shadow, Sep 09 2014 [bungston] I was thinking that the screen would be like a TV screen, with light-up pixels. Since the viewing angle is so narrow, I thought laser beams instead of LEDs. Each pixel could be like a mile across, easy. Colored mirrors and sunlight would work some of the time, and the methods could interleave.
I thought projecting from Earth would be interruptable and scary powerful. (The present moon is too dark a color, BTW.)
If you want a rear-projection screen, you would have to make a big cone, not an Eiffel tower.
As for eclipses, we could get a better view of Earth's shadow during lunar eclipses. I hadn't thought of eclipses .... we could have solar eclipses more often.
// wall of text // Erm, you might want to skip my next moon idea.
[2 fries], I missed your Lunark idea while checking for priors. I seem to have voted for it at some time in the past, and rightly so. Hmmm.-- baconbrain, Sep 10 2014 Practical and cost effective, what's not to like about this plan! Can you affix a nozzle to the moon that shoots popcorn back to Earth on movie nights?
Splendid idea! I give it two buns up! [+] [+]-- Grogster, Sep 10 2014 You could rely upon reentry to pop it. Unless you wanted a popcorn ball meteor. I wonder how big it would have to be to have one popped kernel left by the time it hit the pavement?-- RayfordSteele, Sep 10 2014 I've sometimes thought we should change the moon into a series of rings but this works too. [+]-- Voice, Sep 10 2014 You can borrow my nuclear-powered robotic rhinoceroses, they're not doing anything right now but tearing up the lacrosse pitch at the Heathen Institute for Inadvisably Applied Science & Sabbatical Squandering. Be aware that the anal aperture jets may need calibration.-- Alterother, Sep 12 2014 /I suspect that this is not sufficiently true/
Imagining the gravity felt on an expanding sphere of moonstuff centered on the original center of mass of the moon. Would the gravity perceived correspond to the distance from the center of mass, regardless of sphere size?-- bungston, Sep 12 2014 Interesting question. Using the equation c=3 we can conclude I have drawn a small penis.-- rcarty, Sep 12 2014 Well, I'll be darned. It all adds up... that **IS** a really small penis!-- Grogster, Sep 13 2014 [bungston], I linked to Wikipedia on Surface Gravity. Sir Isaac Newton said that the mass can considered to be concentrated at the center of a sphere. Gravity diminishes with distance away from that center, whether you are standing on a tower, or have foamed the whole planet up after you.
Inside the sphere is different, but generally, anything in layers above your depth cancels out, and can be ignored. So in a hollow sphere, there is no weight.-- baconbrain, Sep 13 2014 Inhabited, no doubt, by Moonataurs.
//ruin eclipses// put a bit of spin on the structure and the eclipse becomes a light show.-- FlyingToaster, Sep 13 2014 I was under the impression the moon was made of cheese, for some reason. So let's have some Cheetos with our movie.-- blissmiss, Sep 13 2014 [NotationToby], it is indeed similar to your idea. Yours even mentions multitiered aqueducts in your anno. Hmmm.
I can't recall seeing yours, and I did not annotate or vote on it. I did not think to search the "terraforming" category.-- baconbrain, Sep 17 2014 Well, you could boost the effect, by simultaneously making the Earth smaller.
Probably best done railgunning Earth rocks up to the moon.
At some point a choice would have to be made about which one is now the Earth, and a total bugger for anything using the lunar calendar.-- not_morrison_rm, Sep 17 2014 random, halfbakery