Questions tagged [light]

For questions concerning electromagnetic radiation in the visible spectrum.

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96
votes
9answers
17k views

What could make a star green?

Stars are never green. When a star's spectra "peaks" in the green range, it also releases a significant number of waves of the adjacent colors - so "green" stars appear yellow or white. I want a ...
43
votes
5answers
6k views

How do seasons work in a binary system (planet orbits one star, not both)?

I have a planet orbiting one star in a binary system. When the planet is exactly between the two stars it will experience a double day; when the primary sun sets the secondary one rises, no overlap. ...
39
votes
8answers
6k views

What light colors/bulbs should be used inside a spaceship?

I've noticed in recent scifi shows/movies such as the Expanse or Star Trek that the lighting inside spaceships have two characteristics: Punishingly blue lighting Dark/dimmed miscellaneous lighting ...
34
votes
13answers
7k views

What does the view outside my ship traveling at light speed look like?

World Rules: Travelers are able to move at the speed of light without disruption of their lives. Time passes "normally" for them. They think, breathe, love, cry, and steer the ship as if they were ...
33
votes
8answers
7k views

A monochrome planet

I am asking if a planet with shades of gray only is scientifically possible in our universe. Basically everything on the surface of this planet would seem black and white to the human eye. Here are ...
32
votes
8answers
6k views

How would lighthouses work in space?

In my world spaceships are guided by lighthouses floating in space instead of electronic navigational systems. A lighthouse in space has the shape of a huge sphere emitting intense red light. Like the ...
26
votes
5answers
6k views

How reflective is blood?

If you were on a raft in say, an ocean of blood, and it was very still, would you be able to see the stars of the night sky reflected in it? Would you be able to see your own reflection? How far down ...
25
votes
16answers
6k views

How to make sure humans do not know the meteorological phenomenon rainbow?

You've got to love the rainbow, it's an awesome sight. But I don't want humans to have the pleasure of seeing the rainbow. What change to the earth, atmosphere and so on, is needed so that humans ...
24
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7answers
6k views

What does a solid, 1 mile diameter subterranean glass sphere look like?

There is a solid glass sphere that is 1 mile in diameter. It is completely covered in dirt and rock, except for one small room that is built adjacent to the sphere. One of the four walls of this ...
22
votes
13answers
8k views

Metal that glows when near pieces of itself

First question! I'm excited to see if anyone can help me. Any missteps are unintentional, but feel free to tell me so that I may learn. So, I've recently started brainstorming over a possible story, ...
22
votes
17answers
4k views

Evolution of a creature that uses light as a weapon

On our world we have any number of creatures that use: Noxious Chemicals Poison(Spiders and Snakes being the obvious examples) Sound Electricity as an alternative to their teeth and claws. One ...
22
votes
13answers
4k views

Always a full Moon for the Emperor - Can this be achieved with solar panels and LEDs?

The Emperor of the World wants there always to be a full moon. His Scientific Advisor (the SA) comes up with a plan. He plans to cost out the venture, hand it over to the Keeper of the Treasury who ...
22
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18answers
6k views

Are there any medieval light sources without fire? [closed]

In a world of my story, which is loosely based on medieval times, fire disappeared. Are there any sources of lighting without fire that would be possible in a medieval setting? It is a fantasy book ...
21
votes
11answers
5k views

Could there be a material that inverts the colours seen through it?

I had a vision of a creature that touched things, and wherever it touched, it left a mark opposite to the original colour. For example when it walked across the grass the grass had red footprints, ...
21
votes
5answers
3k views

What are the main problems with beaming light from the Sun to Saturn?

I recently finished reading the Kim Stanley Robinson novel 2312 - set, of course, in the year 2312. Part of the background to the political negotiations and ongoing terraforming in the outer Solar ...
20
votes
3answers
1k views

How large of a telescope would one need in order to read someone's lips on a planet light years away?

If I wanted to image an Earth-like planet at a resolution where one could read the lips of a human speaking on the surface 1, 10, and 1000 light years away, how large would the telescope reflector ...
20
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10answers
1k views

Compressed air lighting?

So I've got this civilization that doesn't have electricity, but does have municipal power distribution via compressed air lines. Now, you can do a lot of useful things with compressed air. Even in ...
19
votes
8answers
12k views

Car headlights in a world without electricity

In a world like ours in the 1980s, but which for whatever reason does not use any form of electricity. (Either it does not exist or batteries and generators etc have not been invented.) For purposes ...
19
votes
5answers
4k views

How much light is too much?

A mage has created an amulet of light. It shines light from one side, and the user is capable of controlling the color and intensity of that light. In an effort to avoid abuse, the mage has limited ...
18
votes
5answers
4k views

Can visible light be blocked while still allowing for light for plants to survive to pass through?

What I'm thinking for this question is that some kind of filter is put around the sun by aliens that prevents some kinds of solar energy from passing through but allows other types. Like if it ...
18
votes
5answers
1k views

How can I safely brighten my secondary star?

I have an earth-like planet orbiting one of the stars in a binary system. I have learned that, for G-class stars, if the secondary star is 100AU from the primary one, I can expect the secondary star ...
17
votes
3answers
1k views

Apparent Color of the Sun and Sky

The game Rodina features four planets, all with different colored skies. For some reason, the sun is a different color from each planet's surface (use this guide for reference). The four planets, in ...
16
votes
5answers
5k views

Using light as a barrier to block people without grilling them

We know that light exerts pressure upon matter. I'm imagining a hallway where an intense light source on one end shines towards the other end. The goal is to have the beam of light exert so much ...
16
votes
5answers
3k views

How would a microscopic organism create kilometre long fibre optic cables from ice

My story premise is that a human expedition to Europa has happened and the travellers have tunnelled through the ice and formed a colony in the ocean. When they breached into the ocean, they ...
15
votes
6answers
4k views

How to create electric light with 1300s technology

I would like to have electric light bulbs. One should be at least as good as a candle. What we have: The technology level is generally early 1300s But we can create copper wire We have a ...
15
votes
6answers
13k views

Does mirror armour work against laser guns?

The next war will be fought with lasers beside computers, I'm wondering could a bullet proof vest coated with a highly reflective surface protects user from laser blast. The laser in question is ...
15
votes
3answers
1k views

What would this nebula look like from a planet?

I have a binary system. The primary star is F- or G-class; the secondary is K-class, 20AU away, and in a small reflection nebula (suggested here). A planet orbits the primary in the habitable zone. ...
13
votes
4answers
1k views

Full-body bioluminescence

A creature I am imagining is a small mammal about the size of a domestic cat which - through symbiotic bacteria which live in its fur - is covered its whole body over in blue-white bioluminescence, 24-...
13
votes
3answers
2k views

Is it really possible to see across a ringworld? [duplicate]

Almost all illustrations of ringworlds that I've come across tend to show off the shape of the ringworld from the surface. This doesn't seem realistic to me, because the ringworld's radius would ...
13
votes
7answers
18k views

How would lack of sunlight affect a human population?

Other than photosynthesis being an issue, if the Earth's surface became inhospitable and humans were forced to live underground, what biological changes would they be expected to go through to adapt ...
12
votes
8answers
3k views

Trap light in a cage [closed]

Is it possible to build a mirror cage in order to catch light in it? Let's assume the surface of the mirror reflects absolutely 100% of the light. Which shape of cage is the best to do this? Is it ...
12
votes
6answers
3k views

How can I set a moon on fire?

So, for reasons which may or may not pop up in a later question of mine, I need to light a small Moon-like moon on fire. Well, sort of. See, I need a small object capable of emitting a lot of light - ...
12
votes
4answers
637 views

Would a circumbinary planet have a differently colored sky depending on which star was visible?

One of the things that affects the color of the sky is the wavelengths of light that the star emits, like the image in this question. Here is the image again: If you are standing on a circumbinary ...
12
votes
1answer
273 views

Would Rayleigh scattering (blue skies) be noticeable in an O'Neill cylinder?

In my story there is a full size (Island Three) O'Neill cylinder, 5 miles in diameter and 20 miles long. It doesn't have windows, but is lit internally down the center of the cylinder with a 20 mile ...
11
votes
4answers
1k views

Blacklight Star

Tangentially related to The evolution of neon kittens Is is possible for a star to radiate in the ultra violet spectrum but not much in the visible light spectrum? If not, is there any mechanism ...
10
votes
3answers
3k views

Is it possible to create light that imparts a greater proportion of its energy as momentum rather than heat?

This is yet another question concerning lasers as employed by sorcerers in a particular fantasy setting, but this one pertains to the momentum that photons possess and whether it's possible to ...
10
votes
7answers
3k views

Would a sapient being sensitive to polarized light be able to see the angle of polarization in a photograph?

Many animals have the ability to see polarized light (or rather, are sensitive to the direction of polarization), most notably birds and bees but also a wide range of other animals including ...
10
votes
8answers
3k views

Could a world with a extremely bright night sky exist?

How could an Earth-like tidally locked planet with no Moon have a bright and livable night sky? The bluish night sky should look like this: But it should be 1% as bright as Earth's day sky and ...
10
votes
3answers
1k views

Deflecting lasers/plasma bolts/blaster bolts with lightsabers [closed]

In Star Wars, there's some shots where Jedi deflect lasers with their lightsabers. I know there's a law that says you can't go faster then the speed of light and lasers are light, so what is the ...
10
votes
4answers
3k views

How do vampires react to passive UV light sources?

Certain fantasy creatures are extremely sensitive to concentrated UV light. eg modern vampires. They either slowly or rapidly burn up in-front of you when exposed to direct sunlight or modern high ...
10
votes
3answers
1k views

Can we identify distinct “colors” beyond visible light?

Let's talk about the visible light "rainbow" In almost all depictions of the electromagnetic spectrum, visible light is shown as a rainbow, and adjacent parts of the spectrum are monotone in color - ...
10
votes
3answers
1k views

What would the eyes of a cave-dwelling race be like?

So here's the deal: In a D&D-fantasy-style world, the continent of Archaon is inhabited by a wide variety of elves, whose physical characteristics vary based on their dwellings. The forest elves ...
10
votes
4answers
1k views

What could make a star violet?

Part of a series I'm starting since the recent What could make a star green? did quite well and others could use the information here in their worlds. There aren't any "violet" stars. When a star ...
10
votes
6answers
561 views

What light would my cloudy planet receive from a red dwarf star?

What light spectrum would hit the surface of a planet orbiting a red dwarf star? The planet is a humid greenhouse with a cloudy atmosphere and a strong ozone layer. Over 80% of the surface is water. ...
9
votes
3answers
2k views

Sky color of an alien world

I'm asking for a world I'm making, which orbits a red star. According to this image, there is a star that would make the sky white. What would the sky look like during sunrise and sunset on a planet ...
9
votes
1answer
846 views

Ultraviolet bioluminescence

Bioluminescence is badass. It involves living beings emitting bright light in the visible spectrum. Would it be, though, possible that a lifeform emits UV (ultraviolet) light? Does it occur in ...
9
votes
2answers
642 views

How would sunlight work in the area of shared atmosphere of a Rocheworld?

(See diagram) Presupposing that a Rocheworld can even exist... I imagine that sunlight would work more or less the same in the atmosphere of any part of an Earth like planet that was tidally locked ...
8
votes
5answers
1k views

A more alien world: Flora

In the (relatively new) Star Trek movie Into Darkness, we see Dr. Bones and Captain Kirk in a world composed mainly of red plants. Obviously these are just eye candy with no real basis behind it, but ...
8
votes
8answers
1k views

Is radar better than visible light in deep space?

On the earths surface, radar is pretty sweet. It apparently penetrates the atmosphere well and bounces back and can be detected. I think this has to do with the wavelengths absorbed by our ...
8
votes
4answers
1k views

What would mer-folk use as lights and soft surfaces

I'm writing a story where one of the main races is orca (killer whale) mer-folk. Being orcas need to breath oxygen from the surface so do they, this said they live in a halfly submerged cave...but it'...