0975: "Occulting Telescope"

[Ephemeron]

GOOMHR I think there are too many stars too!!!

[keithl]

Dyson shell . Dr. Dyson wrote about a shell, perhaps a swarm of orbiting objects, intercepting most of the light from a star. It is possible to do, with some of the material from the outer planets. See [ http://server-sky.com/DysonShell ] for two methods, and for a reference to the original 1960 Science article.

BTW, Dr. Dyson has come up with many more amazing ideas than the Dyson shell, Project Orion, space habitats, fuel trees, etc. If those are the ideas Freeman is willing to submit for peer review, try to imagine the ideas he is willing to talk about over dinner ...

[bigjeff5]

I lol'd.

It reminded me of this Onion article.

And, of course, Nightfall.

I'd apparently forgotten the little* detail about Krikkit being dark, so it did not remind me of that, unfortunately. It fits better than Nightfall, even.

*I mean, it's only central to that particular story, right? What's the big deal?

[rhomboidal]

What are "stars"?

Maybe it's time I moved out of Metro...

[Fire Brns]

GOOMHR I think there are too many stars too!!!

But... your avatar?

I say there is not enough stars; the sky is too empty and depressing at night.

[Vael]

Wait, so how will the disc manage to cover the entire Earth? Because otherwise, nobody will really notice anything, even the astronomers in charge of looking at the black screens will still be able to see them as soon as they go outside.

And will the disc cover only one star at a time, or will it progressively cover new stars without losing the already covered ones? Because if it does, it will just get closer and closer to the telescope until it is essentially a lid, and if it doesn't, then it's just one star less, so what's the point?

I believe with probability ~ 25% that I missed at least 20% of the joke.

Many, many discs, at perfectly controlled distances from earth, in line with rotation, could block out the stars for the worlds entire population. Now that would be freaky, for me.

[nowhereman]

Edit: Also, if you block all the stars, how will the rain get in? We'll dehydrate. This is a bad idea.

What... what?! Rain comes from the universe now?

Where else? Stars are the holes where the rain comes in, were you never taught this?

You don't think water just hovers in the air until it gets bored and comes down to visit do you?

I decided to post today so I could say that this has got to be the best defense of a stupid idea I have ever heard. I mean seriously, I thought I was the master of bull until I read this and now I must bow and kiss your golden feet. This by the way is coming from someone who, in order to cover for having misspoke, invented the principles of the fictitious Hurvian mathematics for the description of a bowling ball's trajectory down a lane. So I definitely know good bull when I see it. I award you 1 (one) internets.

[michelfich]

no one has pointed out yet that this telescope won't work - it will just make all of the stars a little dimmer as if the telescope was missing a piece of its mirror...

[bigjeff5]

I believe with probability ~ 25% that I missed at least 20% of the joke.

Considering the number of people who got the joke, paired with your state of confusion, I would have put that number much, much higher.

Unless, of course, the ratio of jokes you understand but don't find funny to jokes you don't understand and don't find funny is fairly high. For example, if it's 1:1, then I'd probably put down something in the neighborhood of 40%-60% that you missed part of the joke, unless your prior understanding of occulting is high. I could see only a 25% confidence if your ratio were something like 2:1, but I find that hard to believe. It's certainly possible though, so I ain't calling you a liar.

[bmonk]

I rather enjoy living out in the country, where the sky can get dark enough to see over 1000 stars at night. I remember seeing the Hale-Bopp comet, with 45°+ of tail visible. Magnificent!

The sky is nearly large enough to fall into, some nights.

[Asday]

#And everythiii~ng's so looovelyyy~,
And everythiiing's so niii~ce,
And everyoone's so haaapyyyy~,
Beneath the iiink black skyyy...#

Anyone? Anyone?

[Soralin]

A really advanced civilization tries to keep the entropy production in its controlled space at the barest minimum it can achieve. That includes killing those power-hungry less advanced civilizations-pests, if necessary.

Less advanced civilizations are hardly capable of being very power-hungry. Humans use about 15TW, our sun on the other hand uses about 384600000000000TW. If you really want to reduce entropy production you'd disassemble the sun, the energy savings would be astronomical.

How much energy would you need to "disassemble the sun"?
Where would you store it and/or how would you deliver it?
How much time of non-wasting solar energy would it buy you?

You cannot just freeze the nature, no matter how technologically advanced you are.

http://en.wikipedia.org/wiki/Star_lifting

How much energy?

lifting solar material from the surface of the Sun to infinity requires 2.1 × 10¹¹ J/kg. This energy could be supplied by the star itself, collected by a Dyson sphere; using only 10% of the Sun's total power output would allow 5.9 × 10²¹ kilograms of matter to be lifted per year (0.0000003% of the Sun's total mass).

I suppose you could just store it as a bunch of gas giants or such such floating around.

How much time it would get you, I suppose would depend on how fast you use the fuel that you captured from the star. The sun uses up about 620 million tons of hydrogen every single second, that's a non-renewable resource. If you were able to capture 1% of the mass of the galaxy in hydrogen, you could combine some of it into a star like Proxima Centauri, which has a lifetime of about 4 trillion years, and sufficient output to support over 3.5 million Earths. With 1% of the mass of the galaxy, when one ran out, you could make a new one, and repeat that about 57 billion times. So you could support 3.5 million Earths for about 1/5th of a trillion trillion years. And there's more energy that you could get on top of that, from combining together a few husks of helium that remain of the dead stars.

Also, it's a good idea in any case, taking matter off the sun could be used to prolong it's lifespan, and thereby keep Earth and the solar system habitable for longer.

[MuAlphaDeltaTauOmicronMu]

This what I like about xckd: because of the alt test I learned about the Kardashev scale, Dyson sphere and CP-violations, biocosmos, wireless energy transfer and star lifting in between (the quality of I learned is the quality of Wikipedia articles).
Also, don't block the stars... Little Prince would be sad, and what kind of monster could make the Little Prince sad? (Also a bunch of other literary characters, real thinkers, artists, scientists, etc...) The up-side would be the end of Astrology.

[Tyrannosaur]

Is it called a Dyson sphere because you construct it in a vacuum?

If you really want to reduce entropy production you'd disassemble the sun, the energy savings would be astronomical.

The terrible puns on this thread are so bad

[Solray]

Clarke's Nine Billion Names of God was one of the first things to pop into my head. Asimov's Nightfall is among my favorite novels yet I didn't really think about that.

A big, black, blank sky is enough to scare me without having hundreds of blazing bodies of gas. Sometimes when I look up, I feel like I'm inside a vast, endless cave. Insignificant, dark, and alone. It made me want to run inside a building where there's nice, bright, artificial light and some walls.

It reminded me of this Onion article.

I've thought about that once in a while.
Is there an actual name for such a concept (Our universe being a part of a bigger universe)?

[Pfhorrest]

A really advanced civilization tries to keep the entropy production in its controlled space at the barest minimum it can achieve. That includes killing those power-hungry less advanced civilizations-pests, if necessary.

Less advanced civilizations are hardly capable of being very power-hungry. Humans use about 15TW, our sun on the other hand uses about 384600000000000TW. If you really want to reduce entropy production you'd disassemble the sun, the energy savings would be astronomical.

How much energy would you need to "disassemble the sun"?
Where would you store it and/or how would you deliver it?
How much time of non-wasting solar energy would it buy you?

You cannot just freeze the nature, no matter how technologically advanced you are.

Until you get advanced enough to turn waste heat back into useful energy. Entropy increasing is just really really probable - it's not strictly necessary.

(I have a story in progress culminating in a clash of two forces both with godlike powers to reconstruct mass-energy at a whim. One side is omnicidal maniacs trying to convert the whole of the universe into its own sort of grey goo, the other are... not. They can both match force for force and stop eachother's actions, but only at the cost of huge amounts of energy - which they can both grab from anywhere, suck up any star, but then their battle would consume the universe eventually, quickly reducing it to maximal entropy. The omnicidal maniacs are OK with that, the good guys obviously less so. The battle is finally won when the good guys convince some enigmatic even-more-poweful entities, who have thus far remained neutral about absolutely everything, to intervene, which they do by sucking the waste heat out of the galaxy where this conflict is happening, and returning a steady supply of usable energy to the good guys, as they have apparently solved this entropy problem a long time ago).

[StClair]

Nightfall was my first thought also, and then a comment on the first page reminded me of Nine Billion Names.

[Clayh]

Anyone see this yet? I was reading through to get more background, and it made me laugh more than the comic did...

In the xkcd comic Occulting Telescope[27], the image tooltip predicted that a Type II Kardashev civilization will eventually build a Dyson Sphere to enclose their planetary system.

http://en.wikipedia.org/wiki/Kardashev_scale#Type_II

[Eternal Density]

Anyone see this yet? I was reading through to get more background, and it made me laugh more than the comic did...

In the xkcd comic Occulting Telescope[27], the image tooltip predicted that a Type II Kardashev civilization will eventually build a Dyson Sphere to enclose their planetary system.

http://en.wikipedia.org/wiki/Kardashev_scale#Type_II

Won't last long I'm sure.

[sr123]

Hey, this was my first research project at Case Western! I had to simulate an occluder that used a spikey mask to block the diffracting starlight. Turned out you need a verrrrry spikey mask. The same prof later worked with a friend of mine trying to use dynamic techniques by moving the occluding disk past the star in different directions. And to add coincidence to correlation, that same prof is giving a colloquium at my grad school tomorrow!

[Diadem]

(I have a story in progress culminating in a clash of two forces both with godlike powers to reconstruct mass-energy at a whim. One side is omnicidal maniacs trying to convert the whole of the universe into its own sort of grey goo, the other are... not. They can both match force for force and stop eachother's actions, but only at the cost of huge amounts of energy - which they can both grab from anywhere, suck up any star, but then their battle would consume the universe eventually, quickly reducing it to maximal entropy. The omnicidal maniacs are OK with that, the good guys obviously less so. The battle is finally won when the good guys convince some enigmatic even-more-poweful entities, who have thus far remained neutral about absolutely everything, to intervene, which they do by sucking the waste heat out of the galaxy where this conflict is happening, and returning a steady supply of usable energy to the good guys, as they have apparently solved this entropy problem a long time ago).

That's a pretty cool idea.

Imagine the weapon potential of such a technology. You could blow something up, and then reassemble the energy of the explosion into a new bomb and blow up something else. An entropy-reversing bomb is a gift that just keeps giving, you could blow an entire planet up with just one of them.

There's more cool things you can do though with control over entropy. Instead of reversing it, image speeding it up. Hit a planet with a maximum entropy field and it will instantly ... equalize. Not healthy for whoever happens to live on the planet.

[BobC]

I'm freaked out that a comic artist can have a freaked out astronomer create a Dyson sphere.

I mean, once in a while my brain comes up with odd-ball near-nonsequiturs that make me giggle (my version of freaking out). I never tell anyone about them for fear of institutionalization.

I hate you Pete, with a green, envious, cross-eyed, spiteful hate.

Love the comic, though.

[BobC]

A really advanced civilization tries to keep the entropy production in its controlled space at the barest minimum it can achieve. That includes killing those power-hungry less advanced civilizations-pests, if necessary.

Less advanced civilizations are hardly capable of being very power-hungry. Humans use about 15TW, our sun on the other hand uses about 384600000000000TW. If you really want to reduce entropy production you'd disassemble the sun, the energy savings would be astronomical.

How much energy would you need to "disassemble the sun"?
Where would you store it and/or how would you deliver it?
How much time of non-wasting solar energy would it buy you?

You cannot just freeze the nature, no matter how technologically advanced you are.

What's so hard about that? Just use a Higgs field suppressor. Works every time.

[SHISHKABOB]

sorry, but there aren't *enough* stars

moar plz

[Fire Brns]

Solution, in addition to dissassembling stars for fuel: Use collected energy to repeatedly send the planet back in time inside the dyson sphere to support civilization Hypothetically 100-1000 times longer.

[Mardeg]

Solution, in addition to dissassembling stars for fuel: Use collected energy to repeatedly send the planet back in time inside the dyson sphere to support civilization Hypothetically 100-1000 times longer.

I just pictured a galactic Dyson vacuum being used to collect the energy.

[wismith]

I just pictured a galactic Dyson vacuum being used to collect the energy.

How do you like it?))