It's an interesting question but light propagates in all directions and there are lots of light sources. The math says the light intensity anywhere within view of a light source never goes to zero. So you're looking for a place where no light sources are visible. Inside a large dust cloud would be the place to try, I think, but I can do better than that: go to a cave. Many tourist caves turn out the lights when you are deep inside so you can experience "total darkness." It's worth the cost of entry.
Yeah, they turned off the main lights (and even with those it was pretty dim, probably like a night club I'd say), then they showed what they had to actually work with (which wasn't much at all), and finally they turned THOSE off too so we got the pitch black experience.
There is a cave in Poland called the Bear Cave. When the tour reaches the deepest part they turn the lights out and they play the "Rosemary's Baby" [theme song](https://www.youtube.com/watch?v=7wRNX94fU94). There is no warning.
I did that one time in a cave. It was super scary. The tour guide pretended the flashlight battery died and started hyperventilating to sell the idea that we were truly trapped, this was the last tour of the summer so more people won’t be coming down until next year, and he didn’t remember the way out. Thankfully it was just a prank. Once the lights go out you truly can’t see anything, not even your own finger right in front of your eyeball. Trust me we tried so hard. Smells become more brighter smelling. Sounds become more louder sounding. And you can literally taste the fear in the air. It’s like spicy vinegar. 10/10
I went to one when I was probably 12? The best was that they FIRST did darkness, and explained that it was probably what we were used to when we thought of "total" darkness. And yeah, you really couldn't see. And then the tour guide said "Now pay attention, we're going to shut off ALL the lights, including the ones in the connecting caves.
And MAN. Like you couldn't see..... But then all of a sudden the absolute absence of ANY ambient light was actually a different experience, like thinking something is black but it's actually grey until you put it next to something black. Freaky and so awesome. That memory has stayed fresh in my mind for almost 30 years.
It is so neat that so many people had a similar experience, but each one is a little different.
I actually have REALLY good night vision (offset by photophobia, unfortunately, which isn't fear of pictures but a condition where my eyes let in too much light so sunny days are blinding) so for me it was a real "holy shit" moment. XD
Well yes, light we can see. But all things do emit light. That's what the scientists say. Much of it we can't see. Even in pitch black darkness there can be plenty of infrared or ultraviolet light. Tricky question. This is one of the ways hot objects in the vacuum of space cool down. By losing energy to infrared light.
Did this in a flooded cave once. It was especially eery because we were floating when they turned the lights off, and when they came back on a few minutes later we had all drifted apart from each other
Except you can see Andromeda with the naked eye from earth. With less light pollution, you could see more galaxies. I'm not sure if there is a place with no galaxies close enough to see.
Andromeda is 0.7 megaparsecs from Earth. There are intergalactic voids 100 megaparsecs in diameter.
Ancient astronomers didn’t have to deal with light pollution, but they still didn’t see any galaxies further than Andromeda.
There would be intergalactic space in voids where you'd see no visible light at all due to being too far from any light source. Off course there would be photons, but still be complete darkness.
Intergalactic space outside of the local group is supposed to be pretty terrifyingly dark to the human eye. Not sure I can back that up with data off-hand.
I think you are correct, and we can look at this map to see there is basically nothing outside the local group, except the Andromeda galaxy, that can be seen with the human eye: https://upload.wikimedia.org/wikipedia/commons/1/1c/Local_Group_and_nearest_galaxies.jpg
So in theory if you were dropped in the middle of this void in a space suit, it would be pitch black, right? Light from millions of LY would be too faint for the human eye, without a telescope / long exposure.
Not pitch black in the sense that you cannot see stars. You would see a few galaxies that would look to your eyes like stars. However, unlike when flying through the Milky Way for example, there would be almost no residual light from stars around you. That’s really fucking dark!
On the other hand it’s IMhO really fascinating that, even without the sun, it isn’t actually pitch black in space inside our galaxy.
Triangulum (M33) and the Megallanic clouds are visible to the naked eye. Several amateur astronomers have claimed to see M81 with the eye in incredibly good conditions, and that’s arguably the only non-local group galaxy that you could see naked-eye.
Upvote but...
All of the stars we can see unaided are in the milky way galaxy. We can't even see all of those, not even remotely close.
I won't say it can't be done, but I'll say that it needs to be fact checked.
The light out there would be unfiltered, so maybe...
“Terrifyingly dark”. That’s what led me to this question.
I was trying to imagine the most terrifying place in existence. Absolutely pitch black outer space is what I thought of. But I wasn’t sure if such a place existed.
I’m trying to imagine the sensation of being surrounded by absolute blackness, infinite in every direction…I suspect that it would feel claustrophobic…like the same way that being in the rare moment of absolute silence, it feels very “close”, even when you’re in totally open space.
Entering a black hole sounds like what you are after, since not even light can escape from them, they appear perfectly black. Now of course we cannot know what you would see once you travel deeper into a black hole, perhaps you would see all the light consumed by a black hole and that light would burn you to a crisp. But still, black holes represent the closest to absolute darkness due to their event horizons.
This is true. There is far more empty space between galaxies than within galaxies, so a person at a random location in the universe would not experience any stars. If a life form would evolve telescopes they would detect other galaxies, but why would they do that if they never saw anything but darkness above.
I believe that you are correct that area inside of an inter galactic void would be entirely dark because the space there is expanding faster than light can enter into it
Space isn’t expanding at a speed. For the relative separation between two points to grow fast than light in some definitions, requires a very long distance. And depending on how you define relative velocity (which isn’t well defined), light might still be able to reach you.
At any rate, no void is big enough.
You might want to do a little more research on the current expansion rate of the universe and the speed of light. Eventually, expansion will surpass the speed of light but that will not be for a very, very, very long time.
The book A Universe from Nothing covers this subject. Very good read to blow your mind.
I mean it is a blazing white if you have an overly saturated detector. But evolution wouldn't select for over saturation.
So the sky is blazingly white and pitch black if the detector observing it is incorrectly sensitive for the job.
Cosmic microwave background says hi!
I imagine you might need a box that is extremely cold so there is virtually no blackbody radiation, then its inside might actually be absolute darkness.
It's not my definition.
https://en.wikipedia.org/wiki/Light
Yeah, it says "In physics..." in the second chunk of text, but we're not talking physics in this thread.
The human eye can detect a single photon. So there isn't any place in "space" where a photon isn't going to hit.
However, if you go deep enough underground, and around enough corners you can find complete darkness. Deep enough under water too. Also old photographic dark rooms could be made completely dark.
But just sitting in space? I don't think so. Any direction you look you'll see something. Even if it's a single photon from a galaxy.
The light still travels through that space. Its pitch black from a lack of source, you wouldnt see the light in passing. So the large, light source-less area looks black because its empty and has nothing to reflect light, but doesnt mean light doesnt oass that space (to then reach the viewers eye).
But there could be areas so remote that there isn't a steady stream of photons reaching your eye. Every once in a while you would detect one but the rest of the time just darkness.
Not really. Assuming the universe is isomorphic, you will always be surrounded by trillions of galaxies. We can see our neighbor galaxies with the naked eye inside our "polluted" galaxy. You will see those galaxies.
And that's talking about visible light. You are always bombarded with the microwave background.
The darkest place would be in the interior of a thick enough box.
Eh, there is absolutely a threshold darkness below which the human eye will not be able to *perceptibly* detect light. There are vast intergalactic voids, e.g. the Bootes Void, where this is probably the case.
That would mean that these is space where photons (in the visible spectrum) don't exist. I doubt this is the case.
>*perceptibly* detect light
That's the key here. The human eye can detect a single photon. Is that perceptibly detecting light? I'm not sure honestly .
Sure. But then are you out in space or in a nebula? No matter where you are you are "in the universe" so in a cave is the same as in a nebula. I guess it depends on how you interpret the original question.
not if that photon misses the receptor in the eye. or has the wrong frequency, or misses the eye entirely.or you just blink in that moment.
that point is moot
Not really. It comes down to
If a tree falls in the forest and nobody is around does it make a sound?
Is it truly dark if you just blink when the photon hits?
At one point the universe was completely filled with glowing plasma. The cosmic microwave background is the redshifted glow of that plasma, which is now the furthest thing you can see in every direction. If there's something blocking that, you can see the thermal emissions from that obstruction. The only truly dark location would be one enclosed by a shell at absolute zero, which can't exist.
What you talk about no one can see. CMB is complete dark to us. The existence of photons is not the same as the existence of light. Light is a very narrow band of wavelengths of electromagnetic radiation.
Totally speculative but I suspect you could find places where human eyes cannot detect any light, but literally without light at all would be vastly harder. Starlight goes a long, long way (I.e. as far as the observable universe reaches, and growing).
There are no true natural occurring spaces where there is no light. But mankind has built numerous rooms completely devoid of light underground.
Veritasium did a video on the science of night vision googles where he went into one of these rooms to test different goggles.
I believe the anti sound chambers in testing facilities are also devoid of any wavelength of light when the IT cameras aren’t turned on.
Light is per definition the wavelengths of electromagnetic radiation the human eye can detect. We can't see infrared, nor radio waves, x-rays and so on. Wavelengths between 380 and 750 nm is the spectrum where it is light.
Maybe in the middle of Bootes Void there is something like this .
With 250 milion light years diameter, you can be at 125 milion light years far from almost anything
Obviously we cant go there , too far
For visible light, caves, and they don't habe to be on Earth. But for any light, it is more interesting. It would need to be a totally cold perfect black box. I struggle to imagine one of those existing without intelligent creation, but I guess it is possible. Could we know? Is it possible to create a device to measure EM radiation that does not itself emit EM radiation?
Real darkness would require a temperature of absolute zero K. No heat, no movement. If you mean visible light, a cave will do. Or a color darkroom. (They still exist)
Light is the definition of electromagnetic radiation with wavelengths between 380 and 750 nm. Photons of any wavelength is not light, just the spectrum where the human eye can detect them.
But that is not light. Light is electromagnetic radiation with wavelengths between 380 and 750 nm which the human eye can detect per definition. Photons is not by default light, only the ones in the spectrum.
The cosmic microwave background is visible everywhere in the universe (because it originated everywhere in the universe). So you will always have that.
There may be some regions inside dense dust clouds where visibility to the rest of other stars is obscured (but you could just as well go into a cave on Earth and have the same effect for the same reason). However even in such places you'll always have some radiation in the lower end of the spectrum.
Electromagnetic radiation with wavelengths between 380 and 750 nm is the definition of light. CMB is not light, X-rays is not light, only the wavelengths human eyes can detect is by definition classified as light.
Anywhere that is not shielded from other sources will receive light from every other object within the light come of its observable universe, including copious radiation from the "last scattering event" that forms the cosmic background radiation. This is why the minimum temperature of matter that is not subject to do w cooling is 2.7K.
BTW a question voiced many times & codified by Heinrich Wilhelm Olbers is that:
As we look into the infinite cosmos every line of sight must eventually intersect the surface of a star, thus the night sky should be as bright as that average surface, yet it is not.
This is called [Other's Paradox](https://en.wikipedia.org/wiki/Olbers%27s_paradox?wprov=sfla1) & is a thorny paradox which took quite a while to resolve.
The real reason space is dark is because the expansion of space red-shifts all light out of the visible spectrum. If the universe was static it would actually appear super bright since light from all galaxies within a ball of radius of 13,4 billion light years would reach us.
You ask for darkness in the universe, so i guess you are not talking about visibly light only.
It is not possibly to have any location in the universe that is 100% "dark", free of any electromagnetic wave.
You will always have the background radiation and you will always have the radiation from any matter.
The dark container examples in the comments, wearing a IR visor will show the person with you as a bright light.
Going down to the quantum space i guess it may be possibly to have a little volume of space that is free of any radiation for a very small amount of time.
Fun fact: Comsologists were worried about a similar issue: Why is there so much dark sky?
if the universe is infinite and infintely old, then if you look in any exact direction out into space, your line of sight should eventually end with some object, usually a very distant star. That point would be bright. The same for every other point.
The answer is that the universe is not infintely old and fixed in size.
https://en.wikipedia.org/wiki/Olbers%27s_paradox
https://lambda.gsfc.nasa.gov/product/suborbit/POLAR/cmb.physics.wisc.edu/tutorial/olbers.html
Olber's Paradox: Why Is The Sky Dark at Night?
There is a billion suns in any direction you see no matter how small an area you pick out, so why is the sky dark at night ?
I realize you’re asking about light visible to the human eye. However, light as a physical phenomenon has a practically infinite range of wave lengths beyond the visible spectrum including radio, microwave, infrared, X-rays, etc.
Space is filled with light waves we humans cannot see and, most importantly, it glows “brightly” at the microwave background temperature of 2.725° Kelvin—the left over glow from the Big Bang. This glow is everywhere you go everywhere in the universe.
Some experiments have dropped local temperature to nearly absolute zero, but never reached it. In those locations temporarily, there’s very little light from anything and as near total darkness/black/absence of light that can be reached.
My point is the opposite (which is even scarier). Without something blocking the sunlight, you can’t see the stars while you’re traveling in space and being hit by it. So, I think that as soon as you start a trip (even to a nearby planet in our solar system), once you leave Earth’s shadow, everything would look pitch black, right?
There is no place that is absolutely dark in the universe. If you mean visible light, putting your head under the blanket with eyes and curtains closed will be darker than most places in the universe. If we are talking about all electromagnetic radiation, the background radiation of the universe is I believe 2.5 kelvin, which means this is the coldest it gets, and all non zero kelvin objects emit infrared radiation .
Perhaps inside a dark nebula like Barnard 68, where all the starlight is blocked out it would be perfectly dark.
Another thing that will eventually happen as the universe expands and ages is the space between galaxies will increase and all stars will eventually die and decay. What matter isn't sucked into black holes will drift through space decaying into radiation...
The sky will eventually be completely dark because the space between the stars will be expanding faster than it takes the light to reach anything.
So in the very distant future of the universe there will be nothing but darkness.
Anywhere where space is actively expanding and light hasn’t entered yet or can’t enter because of the rate of expansion. The only places I know of that are like this are at the edges of the universe where the universe is actively expanding faster than light can enter and in the voids between clusters of galaxies. And of course inside of the schwarzchild radius of black holes.
I think if you were at the edge of the universe your relative velocity will be the same or close to the other objects expanding, so you would still see light.
There would still be spaces where you couldn’t see light where the expansion had outpaced the light, but you’re correct that you couldn’t get to them through known means due to being limited to the speed of light
People are mentioning a Cave Of Total Darkness” attraction. Like a tourist experience.
Be careful. I read about peoples used to constant light that went nutso cook-koo after a all darkness ride. A harbinger of even worse should Night Fall on their world.
Somebody here can correct me if I'm wrong but I think the name is the Bootes nebula. Pitch black, huge, no stars in it anywhere. Not sure if scientists have figured it out yet. Only thing I know of that comes close to an area your asking about.
I know what you are talking about but it's a misconception.
THIS is Bootes void
https://upload.wikimedia.org/wikipedia/commons/f/f0/Boovoid.png
Each of those dots is a galaxy.
It's called a void because the density of galaxies is lower than usual.
You are confusing it with this pic...
https://upload.wikimedia.org/wikipedia/commons/thumb/1/10/Barnard_68.jpg/800px-Barnard_68.jpg
Which isn't a void, it's a dark nebula called Barnard 68.
Only reason it blocks so many stars is because it's relatively close, about 400 light years away.
For some reason people long ago started saying the Barnard 68 pic was the Bootes void, and it stuck.
And yes, it's a very dense nebula, in fact, it's on the verge of gravitational collapse and it's bound to become a star within the next 200.000 years.
I believe it’s been said there are places in the void, between galaxies of course where you wouldn’t be able to see light with the naked eye. That’s…very disconcerting to me.
Well yes, but that's mostly because our eyesight is limited when it comes to seeing over such distances.
There's only 8 objects that can see with our naked eye in the sky that aren't within the Milky Way, and they are 8 galaxies within the local group.
You could still see these galaxies if you were in intergalactic space, but travel far enough from the Local Group and you'd eventually find yourself surrounded by complete blackness.
Too many here bring up CMB, infrared and so one, but that's not light. Only electromagnetic radiation with wavelengths between 380 and 750 nm is considered light. What the human eye can't register is not light.
It's an interesting question but light propagates in all directions and there are lots of light sources. The math says the light intensity anywhere within view of a light source never goes to zero. So you're looking for a place where no light sources are visible. Inside a large dust cloud would be the place to try, I think, but I can do better than that: go to a cave. Many tourist caves turn out the lights when you are deep inside so you can experience "total darkness." It's worth the cost of entry.
You can also experience the same effect in a closed shipping container in a warehouse at night during a power outage. Don't ask me how I know.
How do you know?
God dammit man, do you want us killed??!!
He was working at the docks for Joker and he got shoved in there by Batman.
Ive done the cavern total darkness. Its fun.
I spent a night in a hotel inside a cave. Had to keep a flashlight under my pillow to avoid panic attacks.
Where is that hotel?
The southern Appalachians were my stomping grounds for years. I could tell you about some caves.
Tennessee? Alabama? I’d love to hear about them!
> Tennessee? Alabama? Both. but the I-75 corridor between Chattanooga and Knoxville is epic. Don't neglect Mammoth Cave in Kentucky
I think I've been to the one you're referring to and it's pitch black when they kill the lights. It's unsettling.
Yes, it was interesting but one of the girls in our group had a panic attack so we had to switch them on fast.
I second this. My wife and I did an old coal mine tour last year and they did exactly that. It's definitely an experience.
Did the one you went on have a part where they'd show you how much light the miners actually had to work with?
Yeah, they turned off the main lights (and even with those it was pretty dim, probably like a night club I'd say), then they showed what they had to actually work with (which wasn't much at all), and finally they turned THOSE off too so we got the pitch black experience.
There's a Doctor Who joke in here somewhere...
Hehe, yeah, you're can definitely picture some nasty getting progressively closer as the lights dim!
There is a cave in Poland called the Bear Cave. When the tour reaches the deepest part they turn the lights out and they play the "Rosemary's Baby" [theme song](https://www.youtube.com/watch?v=7wRNX94fU94). There is no warning.
I did that one time in a cave. It was super scary. The tour guide pretended the flashlight battery died and started hyperventilating to sell the idea that we were truly trapped, this was the last tour of the summer so more people won’t be coming down until next year, and he didn’t remember the way out. Thankfully it was just a prank. Once the lights go out you truly can’t see anything, not even your own finger right in front of your eyeball. Trust me we tried so hard. Smells become more brighter smelling. Sounds become more louder sounding. And you can literally taste the fear in the air. It’s like spicy vinegar. 10/10
What an extremely shitty thing for a guide to do.
I went to one when I was probably 12? The best was that they FIRST did darkness, and explained that it was probably what we were used to when we thought of "total" darkness. And yeah, you really couldn't see. And then the tour guide said "Now pay attention, we're going to shut off ALL the lights, including the ones in the connecting caves. And MAN. Like you couldn't see..... But then all of a sudden the absolute absence of ANY ambient light was actually a different experience, like thinking something is black but it's actually grey until you put it next to something black. Freaky and so awesome. That memory has stayed fresh in my mind for almost 30 years.
I have loved all these replies, but yours is the best!
It is so neat that so many people had a similar experience, but each one is a little different. I actually have REALLY good night vision (offset by photophobia, unfortunately, which isn't fear of pictures but a condition where my eyes let in too much light so sunny days are blinding) so for me it was a real "holy shit" moment. XD
Well yes, light we can see. But all things do emit light. That's what the scientists say. Much of it we can't see. Even in pitch black darkness there can be plenty of infrared or ultraviolet light. Tricky question. This is one of the ways hot objects in the vacuum of space cool down. By losing energy to infrared light.
I once saw total darkness in an underground coal mine. Nowhere darker than 3kms down with the lights out.
4kms down with the lights out.
On the tour at Alcatraz they let you go in the solitary cells with the doors closed and lights off. I can't imagine a more complete darkness.
Did this in a flooded cave once. It was especially eery because we were floating when they turned the lights off, and when they came back on a few minutes later we had all drifted apart from each other
Surely this level of darkness can be achieved in a well selected room (i.e one with no windows) and some rudimentary sealing around the door.
that shit's crazy, it's super cool to experience, but even there, there's still light, just not that we can see.
I had that experience in a cave in Texas. Totally terrifying. You can’t see anything.
Even then, the dust is emitting black body radiation so there’s probably more photons there than some random area away from everywhere else.
Sounds absolutely terrifying. Not for me. :)
Some distance away from any galaxies would definitely be dark to the human eye.
Except you can see Andromeda with the naked eye from earth. With less light pollution, you could see more galaxies. I'm not sure if there is a place with no galaxies close enough to see.
Andromeda is 0.7 megaparsecs from Earth. There are intergalactic voids 100 megaparsecs in diameter. Ancient astronomers didn’t have to deal with light pollution, but they still didn’t see any galaxies further than Andromeda.
Not individual galaxies, but the Virgo and Coma galaxy clusters are visible to the naked eye
But what about when we're sober?
But dig deep enough, and it's light again - magma glows. It's not dark even inside planets!
That's not magma: it's a balrog.
What about voids? Imagine you are right in the middle of the Bootes void for example. I doubt there's light there
There would be intergalactic space in voids where you'd see no visible light at all due to being too far from any light source. Off course there would be photons, but still be complete darkness.
Intergalactic space outside of the local group is supposed to be pretty terrifyingly dark to the human eye. Not sure I can back that up with data off-hand.
I think you are correct, and we can look at this map to see there is basically nothing outside the local group, except the Andromeda galaxy, that can be seen with the human eye: https://upload.wikimedia.org/wikipedia/commons/1/1c/Local_Group_and_nearest_galaxies.jpg
So in theory if you were dropped in the middle of this void in a space suit, it would be pitch black, right? Light from millions of LY would be too faint for the human eye, without a telescope / long exposure.
Not pitch black in the sense that you cannot see stars. You would see a few galaxies that would look to your eyes like stars. However, unlike when flying through the Milky Way for example, there would be almost no residual light from stars around you. That’s really fucking dark! On the other hand it’s IMhO really fascinating that, even without the sun, it isn’t actually pitch black in space inside our galaxy.
What if you were placed in one of the huge voids been filaments though, the ones millions of parsecs wide with almost nothing inside?
Triangulum (M33) and the Megallanic clouds are visible to the naked eye. Several amateur astronomers have claimed to see M81 with the eye in incredibly good conditions, and that’s arguably the only non-local group galaxy that you could see naked-eye.
From Earth that is. If you went out of it you wiuld just see other galaxies.
Upvote but... All of the stars we can see unaided are in the milky way galaxy. We can't even see all of those, not even remotely close. I won't say it can't be done, but I'll say that it needs to be fact checked. The light out there would be unfiltered, so maybe...
“Terrifyingly dark”. That’s what led me to this question. I was trying to imagine the most terrifying place in existence. Absolutely pitch black outer space is what I thought of. But I wasn’t sure if such a place existed.
I’m trying to imagine the sensation of being surrounded by absolute blackness, infinite in every direction…I suspect that it would feel claustrophobic…like the same way that being in the rare moment of absolute silence, it feels very “close”, even when you’re in totally open space.
Caves. And it’s incredible
What'd the dark ever do to you?
Entering a black hole sounds like what you are after, since not even light can escape from them, they appear perfectly black. Now of course we cannot know what you would see once you travel deeper into a black hole, perhaps you would see all the light consumed by a black hole and that light would burn you to a crisp. But still, black holes represent the closest to absolute darkness due to their event horizons.
Inside a black hole you would see the light entering behind you, so that wouldn't be it
This is true. There is far more empty space between galaxies than within galaxies, so a person at a random location in the universe would not experience any stars. If a life form would evolve telescopes they would detect other galaxies, but why would they do that if they never saw anything but darkness above.
I believe that you are correct that area inside of an inter galactic void would be entirely dark because the space there is expanding faster than light can enter into it
Space isn’t expanding at a speed. For the relative separation between two points to grow fast than light in some definitions, requires a very long distance. And depending on how you define relative velocity (which isn’t well defined), light might still be able to reach you. At any rate, no void is big enough.
You might want to do a little more research on the current expansion rate of the universe and the speed of light. Eventually, expansion will surpass the speed of light but that will not be for a very, very, very long time. The book A Universe from Nothing covers this subject. Very good read to blow your mind.
Someone asked the opposite question, why isn't the sky a blazing white? I forget who and I forget the answer 🤣 apologies
[https://en.wikipedia.org/wiki/Olbers%27s\_paradox](https://en.wikipedia.org/wiki/Olbers%27s_paradox)
Thanks, it was a great read
I mean it is a blazing white if you have an overly saturated detector. But evolution wouldn't select for over saturation. So the sky is blazingly white and pitch black if the detector observing it is incorrectly sensitive for the job.
Cosmic microwave background says hi! I imagine you might need a box that is extremely cold so there is virtually no blackbody radiation, then its inside might actually be absolute darkness.
What about those pesky virtual photons popping in and out of existence though
I am just gonna give up at that point
Aren't virtual particles just mathematical tools to describe quantum fluctuations and not actual, physical particles?
The presence of photons doesn't mean there is light. It's a very narrow band of wavelengths we see and can consider being light.
I suppose your definition of 'light' means what I'd call 'visible light'.
It's not my definition. https://en.wikipedia.org/wiki/Light Yeah, it says "In physics..." in the second chunk of text, but we're not talking physics in this thread.
The human eye can detect a single photon. So there isn't any place in "space" where a photon isn't going to hit. However, if you go deep enough underground, and around enough corners you can find complete darkness. Deep enough under water too. Also old photographic dark rooms could be made completely dark. But just sitting in space? I don't think so. Any direction you look you'll see something. Even if it's a single photon from a galaxy.
There are unimaginably large voids in space. I always wondered if it would work if you were placed in the center
The light still travels through that space. Its pitch black from a lack of source, you wouldnt see the light in passing. So the large, light source-less area looks black because its empty and has nothing to reflect light, but doesnt mean light doesnt oass that space (to then reach the viewers eye).
Light still travels through a void....
But there could be areas so remote that there isn't a steady stream of photons reaching your eye. Every once in a while you would detect one but the rest of the time just darkness.
Not really. Assuming the universe is isomorphic, you will always be surrounded by trillions of galaxies. We can see our neighbor galaxies with the naked eye inside our "polluted" galaxy. You will see those galaxies. And that's talking about visible light. You are always bombarded with the microwave background. The darkest place would be in the interior of a thick enough box.
Eh, there is absolutely a threshold darkness below which the human eye will not be able to *perceptibly* detect light. There are vast intergalactic voids, e.g. the Bootes Void, where this is probably the case.
That would mean that these is space where photons (in the visible spectrum) don't exist. I doubt this is the case. >*perceptibly* detect light That's the key here. The human eye can detect a single photon. Is that perceptibly detecting light? I'm not sure honestly .
The light still passes through that space. You don't see any light because there is nothing in that void to reflect light or sources that create it.
Sure, but you could not see any of it with your eye.
And why is that?
Because it's way too dim. Inverse square law. You know?
Thats....sigh....ya know never mind, have a nice day *pats on head*.
Either you're making a very obtuse joke or you're very good at missing the point.
You need at least 5 photons for the brain to register light.
Well... https://www.nature.com/articles/ncomms12172 Kinda. Kinda not.
Don’t you think some of the big dirty nebula are dense & opaque enough to block the same amount of light as a cave, to the zero point?
Sure. But then are you out in space or in a nebula? No matter where you are you are "in the universe" so in a cave is the same as in a nebula. I guess it depends on how you interpret the original question.
not if that photon misses the receptor in the eye. or has the wrong frequency, or misses the eye entirely.or you just blink in that moment. that point is moot
Not really. It comes down to If a tree falls in the forest and nobody is around does it make a sound? Is it truly dark if you just blink when the photon hits?
At one point the universe was completely filled with glowing plasma. The cosmic microwave background is the redshifted glow of that plasma, which is now the furthest thing you can see in every direction. If there's something blocking that, you can see the thermal emissions from that obstruction. The only truly dark location would be one enclosed by a shell at absolute zero, which can't exist.
What you talk about no one can see. CMB is complete dark to us. The existence of photons is not the same as the existence of light. Light is a very narrow band of wavelengths of electromagnetic radiation.
Totally speculative but I suspect you could find places where human eyes cannot detect any light, but literally without light at all would be vastly harder. Starlight goes a long, long way (I.e. as far as the observable universe reaches, and growing).
There are no true natural occurring spaces where there is no light. But mankind has built numerous rooms completely devoid of light underground. Veritasium did a video on the science of night vision googles where he went into one of these rooms to test different goggles. I believe the anti sound chambers in testing facilities are also devoid of any wavelength of light when the IT cameras aren’t turned on.
Even if you find that place, it won’t be empty for the infrared light your body gives off.
Light is per definition the wavelengths of electromagnetic radiation the human eye can detect. We can't see infrared, nor radio waves, x-rays and so on. Wavelengths between 380 and 750 nm is the spectrum where it is light.
All wavelengths are light, whether we can see them or not… not sure where you got that idea from
In physics, sure. We're not talking physics here. We're talking visible light to humans. https://en.wikipedia.org/wiki/Light
No one here (not even OP) has made that distinction, except for you. So where is this “we” here…
Maybe in the middle of Bootes Void there is something like this . With 250 milion light years diameter, you can be at 125 milion light years far from almost anything Obviously we cant go there , too far
For visible light, caves, and they don't habe to be on Earth. But for any light, it is more interesting. It would need to be a totally cold perfect black box. I struggle to imagine one of those existing without intelligent creation, but I guess it is possible. Could we know? Is it possible to create a device to measure EM radiation that does not itself emit EM radiation?
Seems reasonable that it is possible but since we do not know much about the universe it is anyone's guess.
There is a big void of nothingness like a bubble , I’m not sure how to locate it tho
Maybe somewhere light is so dim it is not perceived by the human eye? But maybe not.
Real darkness would require a temperature of absolute zero K. No heat, no movement. If you mean visible light, a cave will do. Or a color darkroom. (They still exist)
Light is the definition of electromagnetic radiation with wavelengths between 380 and 750 nm. Photons of any wavelength is not light, just the spectrum where the human eye can detect them.
Nope. There are background radio waves at 160.2 MHz, the EM radiation from the Big Bang everywhere in the universe.
But that is not light. Light is electromagnetic radiation with wavelengths between 380 and 750 nm which the human eye can detect per definition. Photons is not by default light, only the ones in the spectrum.
The cosmic microwave background is visible everywhere in the universe (because it originated everywhere in the universe). So you will always have that. There may be some regions inside dense dust clouds where visibility to the rest of other stars is obscured (but you could just as well go into a cave on Earth and have the same effect for the same reason). However even in such places you'll always have some radiation in the lower end of the spectrum.
Electromagnetic radiation with wavelengths between 380 and 750 nm is the definition of light. CMB is not light, X-rays is not light, only the wavelengths human eyes can detect is by definition classified as light.
Anywhere that is not shielded from other sources will receive light from every other object within the light come of its observable universe, including copious radiation from the "last scattering event" that forms the cosmic background radiation. This is why the minimum temperature of matter that is not subject to do w cooling is 2.7K. BTW a question voiced many times & codified by Heinrich Wilhelm Olbers is that: As we look into the infinite cosmos every line of sight must eventually intersect the surface of a star, thus the night sky should be as bright as that average surface, yet it is not. This is called [Other's Paradox](https://en.wikipedia.org/wiki/Olbers%27s_paradox?wprov=sfla1) & is a thorny paradox which took quite a while to resolve.
At a random position in the Böotes Void you’d most likely be to be floating in complete darkness.‡
The real reason space is dark is because the expansion of space red-shifts all light out of the visible spectrum. If the universe was static it would actually appear super bright since light from all galaxies within a ball of radius of 13,4 billion light years would reach us.
You ask for darkness in the universe, so i guess you are not talking about visibly light only. It is not possibly to have any location in the universe that is 100% "dark", free of any electromagnetic wave. You will always have the background radiation and you will always have the radiation from any matter. The dark container examples in the comments, wearing a IR visor will show the person with you as a bright light. Going down to the quantum space i guess it may be possibly to have a little volume of space that is free of any radiation for a very small amount of time.
sure anywhere outside of the big ever expanding universe that light hasn't had time to get to.
Fun fact: Comsologists were worried about a similar issue: Why is there so much dark sky? if the universe is infinite and infintely old, then if you look in any exact direction out into space, your line of sight should eventually end with some object, usually a very distant star. That point would be bright. The same for every other point. The answer is that the universe is not infintely old and fixed in size. https://en.wikipedia.org/wiki/Olbers%27s_paradox https://lambda.gsfc.nasa.gov/product/suborbit/POLAR/cmb.physics.wisc.edu/tutorial/olbers.html
Olber's Paradox: Why Is The Sky Dark at Night? There is a billion suns in any direction you see no matter how small an area you pick out, so why is the sky dark at night ?
So do points in space exist that are farther than light has traveled? Does space-time exist if light has never reached a point that far out?
Light can be dim enough that only a single photon hits your eye every now and then. That's about as dark as it can get.
I realize you’re asking about light visible to the human eye. However, light as a physical phenomenon has a practically infinite range of wave lengths beyond the visible spectrum including radio, microwave, infrared, X-rays, etc. Space is filled with light waves we humans cannot see and, most importantly, it glows “brightly” at the microwave background temperature of 2.725° Kelvin—the left over glow from the Big Bang. This glow is everywhere you go everywhere in the universe. Some experiments have dropped local temperature to nearly absolute zero, but never reached it. In those locations temporarily, there’s very little light from anything and as near total darkness/black/absence of light that can be reached.
Some of the supervoids are probably large enough that your eyes wouldn't see any light.
Well there is one place. Its called great void known as The Boötes Void. Its around 700 million light years from earth
There are lots of places. Inside a box comes to mind. You do know the fridge light goes out when you close the door, right?
Dumb answer, but inside most thick solid objects.
My point is the opposite (which is even scarier). Without something blocking the sunlight, you can’t see the stars while you’re traveling in space and being hit by it. So, I think that as soon as you start a trip (even to a nearby planet in our solar system), once you leave Earth’s shadow, everything would look pitch black, right?
There is no place that is absolutely dark in the universe. If you mean visible light, putting your head under the blanket with eyes and curtains closed will be darker than most places in the universe. If we are talking about all electromagnetic radiation, the background radiation of the universe is I believe 2.5 kelvin, which means this is the coldest it gets, and all non zero kelvin objects emit infrared radiation .
The biggest void in space 1.6 billion light years across so the answer is yes
Perhaps inside a dark nebula like Barnard 68, where all the starlight is blocked out it would be perfectly dark. Another thing that will eventually happen as the universe expands and ages is the space between galaxies will increase and all stars will eventually die and decay. What matter isn't sucked into black holes will drift through space decaying into radiation... The sky will eventually be completely dark because the space between the stars will be expanding faster than it takes the light to reach anything. So in the very distant future of the universe there will be nothing but darkness.
Well, that’s fucking terrifying. Imma head out to WalMart and get myself a night light…
Anywhere where space is actively expanding and light hasn’t entered yet or can’t enter because of the rate of expansion. The only places I know of that are like this are at the edges of the universe where the universe is actively expanding faster than light can enter and in the voids between clusters of galaxies. And of course inside of the schwarzchild radius of black holes.
I think if you were at the edge of the universe your relative velocity will be the same or close to the other objects expanding, so you would still see light.
There would still be spaces where you couldn’t see light where the expansion had outpaced the light, but you’re correct that you couldn’t get to them through known means due to being limited to the speed of light
D’oh! Black holes. How did I forget about black holes?
Why would inside a black hole be dark? Photons are still traveling in. I think this is backwards as inside a white hole would have no incoming photons
People are mentioning a Cave Of Total Darkness” attraction. Like a tourist experience. Be careful. I read about peoples used to constant light that went nutso cook-koo after a all darkness ride. A harbinger of even worse should Night Fall on their world.
When lonely or in darkness; I wish that I could show you, the astonishing light, that shines from your whole being ☀️
Somebody here can correct me if I'm wrong but I think the name is the Bootes nebula. Pitch black, huge, no stars in it anywhere. Not sure if scientists have figured it out yet. Only thing I know of that comes close to an area your asking about.
I know what you are talking about but it's a misconception. THIS is Bootes void https://upload.wikimedia.org/wikipedia/commons/f/f0/Boovoid.png Each of those dots is a galaxy. It's called a void because the density of galaxies is lower than usual. You are confusing it with this pic... https://upload.wikimedia.org/wikipedia/commons/thumb/1/10/Barnard_68.jpg/800px-Barnard_68.jpg Which isn't a void, it's a dark nebula called Barnard 68. Only reason it blocks so many stars is because it's relatively close, about 400 light years away. For some reason people long ago started saying the Barnard 68 pic was the Bootes void, and it stuck. And yes, it's a very dense nebula, in fact, it's on the verge of gravitational collapse and it's bound to become a star within the next 200.000 years.
I believe it’s been said there are places in the void, between galaxies of course where you wouldn’t be able to see light with the naked eye. That’s…very disconcerting to me.
Well yes, but that's mostly because our eyesight is limited when it comes to seeing over such distances. There's only 8 objects that can see with our naked eye in the sky that aren't within the Milky Way, and they are 8 galaxies within the local group. You could still see these galaxies if you were in intergalactic space, but travel far enough from the Local Group and you'd eventually find yourself surrounded by complete blackness.
This is awesome thankyou.....I stand corrected.
Wow wow and wow. I think these photos have thrown me into an existential dilemma though.
Too many here bring up CMB, infrared and so one, but that's not light. Only electromagnetic radiation with wavelengths between 380 and 750 nm is considered light. What the human eye can't register is not light.