Search found 10 matches

by Gan_HOPE326
Wed Feb 17, 2016 9:29 pm UTC
Forum: What If?
Topic: What-If 0146: "Stop Jupiter"
Replies: 60
Views: 30732

Re: What-If 0146: "Stop Jupiter"

I love imagining that this would be an actual issue environmental activists would protest about in an hypothetical far future scenario in which the Sol System is the main trade hub at the core of the powerful Terran Galactic Empire, with thousands of freighters and war frigates using Jupiter daily t...
by Gan_HOPE326
Wed Feb 10, 2016 5:33 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 75071

Re: What-If 0145: "Fire From Moonlight"

Yeah, that was kind of the point. There is no "moonlight", only sunlight reflected by the moon. If you stop energy from escaping the moon while allowing more to enter (using the dyson's mirror with a hole towards the sun), eventually the temperature of the moon will reach ignition point (...
by Gan_HOPE326
Wed Feb 10, 2016 4:45 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 75071

Re: What-If 0145: "Fire From Moonlight"

With a large enough perfect mirror (think of a dyson sphere with sun-tracking hole the size of the moon) you could set the moon on fire with moonlight. You mean with sunlight? I don't think you could set the *Moon* on fire with moonlight because it already receives it and it fares pretty well (you ...
by Gan_HOPE326
Wed Feb 10, 2016 3:07 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 75071

Re: What-If 0145: "Fire From Moonlight"

The moon is a convex surface so it scatters sunlight in all directions rather than focusing it. That's why it can't act as a mirror. Yes and it's also rough so it scatters rather than reflecting geometrically. The issue is, the fact that it DOES reflect light means however that the thermodynamic ar...
by Gan_HOPE326
Wed Feb 10, 2016 12:48 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 75071

Re: What-If 0145: "Fire From Moonlight"

I'm still confused a bit here as to why you wouldn't be able to take, say, 5 ideal convex lenses refracting different points of the moon's reflection and overlap their outputs to get a theoretical max of 500 degrees. It seems to violate the basic thermodynamics argument presented (the cumulative to...
by Gan_HOPE326
Wed Feb 10, 2016 12:26 pm UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 75071

Re: What-If 0145: "Fire From Moonlight"

Someone should conduct an experiment: is it possible to light a fire using sunlight reflected by a sheet of paper/a bright wall. We KNOW it's possible to light a fire using a parabolic mirror: https://www.youtube.com/watch?v=FU_dn4AlXRM and I very much doubt the mirror itself reached a temperature ...
by Gan_HOPE326
Wed Feb 10, 2016 11:54 am UTC
Forum: What If?
Topic: What-If 0145: "Fire From Moonlight"
Replies: 157
Views: 75071

Re: What-If 0145: "Fire From Moonlight"

"But wait," you might say. "The Moon's light isn't like the Sun's! The Sun is a blackbody—its light output is related to its high temperature. The Moon shines with reflected sunlight, which has a "temperature" of thousands of degrees—that argument doesn't work!" I stil...
by Gan_HOPE326
Sun Jan 24, 2016 10:34 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1633: "Possible Undiscovered Planets"
Replies: 104
Views: 17461

Re: 1633: "Possible Undiscovered Planets"

On this graph, I'm confused by the entry for "Earth". Is Randall Munroe saying he's more than 10,000km away from Earth? Well, yes, if you consider the position of the planet to be coincident with its centre, he's approximately 6,371 km from it (the order of magnitude is right, give it a b...
by Gan_HOPE326
Wed Jan 06, 2016 3:01 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1626: "Judgment Day"
Replies: 63
Views: 12102

Re: 1626: "Judgment Day"

Alt-Alt-text: "These are dangerous! They could cause SUCH BIG EMPs!"
by Gan_HOPE326
Fri Oct 09, 2015 12:40 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1587: "Food Rule"
Replies: 86
Views: 13618

Re: 1587: "Food Rule"

This topic is something I think about a lot, so seeing the discussion I couldn't resist registering to give my $ 0.02. Personally I think the analogy with slavery is interesting but somewhat misleading. We think of slavery, we think of the US South, abolitionism, and so on, but I think that's not a ...

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