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/sci/ - Science & Math

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3419381 No.3419381 [Reply] [Original]

So I'm thinking of a story set in a declined civilization. For lighting they use these hollow neutrally buoyant vacuum spheres made of perfectly reflective surfaces. The spheres are dotted with tiny gaps just smaller than the width of hydrogen atoms. They where charged thousands of years ago with an extremely bright source of light and a small portion of the photons escape through the gaps continually creating thousands of years of lighting but they slowly deplete like radioactive decay. These balls are rare and valuable but also dangerous weapons, when one is smashed it causes extensive damage and blindness so its against the law to have one around the king.

whadya think, is my science sound?

>> No.3419399
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3419399

bump for answers

also animooted

>> No.3419408

HOLY HANDGRENDADE

>> No.3419417

Can light get out from a gap small enough to keep hydrogen atoms from getting in? Would the light be monochromatic or could it allow white (multi-spectrum) light. Would quantum jumping fill my vacuum balloons with gas anyhow? I kinda wanted to have them tethered like a balloon on a string tied to a rock.

>> No.3420678
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3420678

bump

>> No.3421390
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3421390

I'm beginning to think no one on here knows science at all.

>> No.3422183
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3422183

>> No.3422199

Naw man, it needs to go like this:

Everything just got nuked and bad guys are everywhere robbin and killin and shit and the good guy finds some other good guys and they beat the head bad guy then there is an ambiguous ending with the hope of reconstructing their old world.

>> No.3422215

I'm skeptical of the perfect reflectors. ANY absorption at all is going to kill ALL of your light in no time. Light moves quickly.

>> No.3422225

>>3419381

If you can see the light, that means light is getting out. So no, your science isn't sound and neither is your common sense.

>> No.3422342

Why would the light go out slowly?
I mean, it's good for a fantasy, but you're supposing serious technical advances (perfectly reflective surface, extremely long-life thin film structure, extremely intense light source) to replace the production of something as simple as light -- which is quite easy.
I have to figure that even in your example, the light could last a few seconds or minutes, but if this device (made to last thousands of years) were broken by a technology vastly inferior (?) that all it would produce is brightness -- what kind of damage do you suppose?

>> No.3422363

>>3422225
Only a tiny portion of the light gets out, perhaps one photon per trillion per second, so the luminosity would have a half life of like 30k years. The sphere would hold around 10^44 photons.

>> No.3422375

>>3419381 perfectly reflective surfaces

That's what we call a violation of the laws of physics.

>> No.3422411

>>3422363
>10^44 photons

Have you considered how much that would weigh?

>> No.3422433

Releasing all that energy at once would do a hell of a lot more than blind you.

>> No.3422438

>>3422363
That makes no sense. The intensity of light is given by radiant flux divided by the solid angle. In other words, it's directly proportional to the amount of photons shooting out of the light source.

If the photons get out really slowly (as I guess you were proposing) your light source can't be "extremely bright" at the same time.

LOL-captcha: proton asingle

>> No.3422442

>>3422411
Before anyone else speaks up, he's absolutely right, in GR any energy density curves spacetime (produces gravity).

>> No.3422449

>>3422411
>photons
>weight

>implying photons have non-relativistic mass

>> No.3422450

>>3422438
Not that guy, but 10^44 is a big number. You can have a "bright" source that still takes a long time to deplete. But,
>>3422411

>> No.3422461

>>3422449
When numbers are that large, you need to check whether the classical picture is still valid.
>>3422442

>> No.3422491

>>3422450

Uh, given the scales in which we are moving here, it's not that much, we are talking about photons after all.

Actually, it's non-sense to talk about storing photons in a big ball. Light is made of quanta, particles and waves at the same time (plus some other qualities unrelated to both), with zero mass. How the hell are you going to keep them in place?


Again, for the pros at >>3422411
>>3422450
zero mass = no weight

>> No.3422507

>>3422491
>Uh, given the scales in which we are moving here, it's not that much, we are talking about photons after all.
No. "Shut up and calculate". Intuition cannot be applied to numbers like 10^44.

>zero mass = no weight
Not in GR. Any energy density appears in the tensor, and curves spacetime (produces "gravity")

>> No.3422526 [DELETED] 
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3422526

>>3419381

>natural /fit/izin
>goes on /sci/
>clicks on first thread i see
>read first post
>wat
>my face when
>i don't belong here

>> No.3422544

>>3422507
(cont)
This isn't the proper GR calculation, but 10^44 photons with 3 eV each gives us the same total energy as a mass of 5*10^8 kg. So, 500 million kilograms.

How big are these spheres? If they're dense enough, I'm not sure if rocks can hold them up.

>> No.3422584

it would be better if the sphere is filled with something that slows the light down to almost standstill, this will mean you dont need a reflective surface on the inside and you also dont lose anything because of non-perfect reflection.

something like this:
http://news.harvard.edu/gazette/1999/02.18/light.html

although it would still weigh a fuckton.

>> No.3422609

>>3422584
In that case it's really just energy stored in some other form which is more stable. Photons themselves always travel at c, and apparent changes in the speed of light are due to repeated absorption, delay, and emission.

>> No.3422623

>>3422609
it gets the job done, and with less problems than a perfect reflector.

>> No.3422630

>>3422623
True.

>> No.3422730

http://www.betalight.nl/html/index.php?page_id=99

>Betalights or Tritium lightsources are illuminated by means of borosylicate glass tubes covered on the inside with phosphor powder and filled with gaseous tritium. The gaseous tritium emits electrons, which activate the phosphor powder producing light for 15 years (131000 hours).

>> No.3424613

>>3422730
I thought about that but the half life is too low for my story and I don't want to deal with the complications of radiation that would come with something bright enough for my purposes and it would change the dynamic of its violent potential.

>>3422584
>>3422609
I was unaware, is that how a Bose–Einstein condensate really works? Things like electromagnetically induced transparency are beyond my level of education. Though I would really like to learn about it. In any even something that slowed the light down would also make small amounts of imperfect reflections less damaging but how would I keep it at the near zero k temperatures that are required.

>> No.3424633

>>OP is talking about decay

>>using some really convoluted light trap

Just use radioactive rocks, seriously. They have pretty much the same effect, right down to the big explosion if you smash them really hard.

>> No.3424643

cool idea, I think I'm gonna steal that for my story thanks

>> No.3424645

>>3424633
its just a sphere that's shiny on the inside and has a few little holes, whats so convoluted about that?