Why is Universe Dark?

Olbers’ paradox, a part of astrophysics and physical cosmology, is basically a squabble about the sky being dark at night. This paradox is also phrased as the ‘dark night sky paradox’. The paradox states that an inert, considerably old universe with an equal number of stars scattered in the proportionately large space should be bright rather than being dark at night. The question of sky being dark at night might seem ridiculous with a much obvious answer, and the topical answer might surprise you. This question has been studied by the best physicists who have reached an answer that is simple but not so obvious. In order to find an answer to the Olbers’ paradox, the scientists and physicists had to struggle a lot to learn about the behavior of energy involved in the concept. One argument given by the scientists against the dark night paradox is that the light of distant stars might be hidden by the dust clouds. But this answer is again contradicted by the statement that these dust clouds should reach the temperature of the stars by their heat. Another statement contradicting the Olber’s paradox is that these distant stars might be too tiny and far that they can be seen in the vicinity. Besides, there might be numerous stars at increasing distances such that their smaller perceptible size is formed of by their bigger numbers. Another theory is of the time and age of the universe. Universe is 13.73 billion years old which states that light of the starts had certain time to light up the universe. Most of the starts we see today, in our night sky, do not exist anymore. We can see their light because it takes ages for their light to travel around the universe. So we could say that stars in the universe had certain amount of time to contribute to the illumination of the whole universe. Please read comments bellow for additional theories. However, as much as we searched this subject, it still remains a paradox.

33 Comments on “Why is Universe Dark?”

  1. I think that the conclusion here is wrong. What’s really happening is that the constant expansion of the universe stretches the light waves out- through what is known as the Doppler Effect- and converts them into longer wavelengths. These light waves are so stretched that they become microwaves.

  2. Hello. As a doctor, I can tell you that you guys are thinking too much making problems where there aren’t any :))

    The universe is not really dark and the math conclusions are right.
    Our eyes would be destroyed by the light of the day sun, so our own sensors are diminishing the light and actually because of this the night is dark. We also have build all of our instruments to mimic our eye sight. Try making a photo of the night sky with everything on max to reduce the darkness and you will see a bright image. Actually the universe is pretty much different than our senses are able to feel it.
    The only problem here is that our sun is too close to us (compared to the rest of the universe) so its light is too powerful for our eyes, so we had to adapt … this is why we see darkness where there’s actually light. I hope I was clear enough.

    Thank you for reading.

    Sorry for my bad english, but this problem isn’t a problem and not at all a paradox, unless you really want to make one out of nothing.

  3. it is simply because man has to sleep… that’s why night is dark hahaha… no need for scientific explanation… just a coconut shell that functions logically…

  4. The situation is not nearly as complicated as this article makes it out to be. Because each star is so far away from us (trillions of miles), their light is greatly diffused. Because only a very, very small part of each star is aimed precisely at us we only get a tiny fraction of the radiant energy emitted by each star. And the reason we never see the rest of the light is because space is a vacuum and so the light never hits anything. Sometimes light from stars (and from our own star) hit cosmic objects (the moon, meteors, planets), and light does reflect toward us. Often when this happens, however, the amount of light that comes to us is so small that it’s undetectable without special equipment.

  5. The reason for the universe to be dark is that any form of energy[specially light] does not want to reveal its identity unless it comes in contact with any particle i.e. collides. That is why the region around the sun is dark. Even due to the presence of stars and light emitting bodies the universe looks dark.

  6. Like every radiation of energy Light also has dual nature-wave and particle. when a particle strikes any obstacle it reflects or completely deforms. Same story with wave,when it is obstructed by some means. The universe is drastically filled with ‘The Dark matter'(unknown matter) and it’s mass is 98% of the total mass of the universe.Hence a bulk part of light from stars are absorbed by these dark matter and the universe looks dark.
    Thank you for reading this post.
    Here is a link to know more about dark matter.

  7. universe always remains dark…As we know that, any light is visible to us only when it is hit by any object…so, when u travel in space, u would be lighten by sun’s light but your surroundings remains dark as it is free space..

  8. For Christ’s sake, guys, look at a Cosmic Microwave Background image. Microwaves are all over the place. Doppler effect. Simple as the big bang theory. (as long as you’re not trying to figure out what caused the big bang.)

  9. I think everyone is over thinking this. Dark-matter, Microwaves, Doppler?

    We can only see light that enters our eyes. ’nuff said.

  10. There are certain things in world which has no answer or can be given ans this is one of them, and thats why we are called human and there is a belif which says GOD

  11. Ben wrote:
    For Christ’s sake, guys, look at a Cosmic Microwave Background image. Microwaves are all over the place. Doppler effect. Simple as the big bang theory. (as long as you’re not trying to figure out what caused the big bang.)

    thats just stupid noone cares about all this stuff. come on the average person dosn’t give two cents about why the universe is dark until you people mention it
    just wait a while and i am sure something more interesting and answerable will come along.

  12. It might be because in order for light to be seen, it must have something to bounce off. There is no edge of the universe, and the only thing faster than light is the expansion of the universe. So light cant bounce off the edge, and seeing as there are no particles in space like gases in air, light cannot be reflected off that. Black holes also contribute, seeing as they cannot be seen and would absorb light, black being the absence of color (white light being every color).

  13. Christopher M.K. wrote:
    Light dissipates over distance…duh. get a flashlight and try it yourself.

    First of all…
    Your example is wrong. The light coming from your flashlight does not dissipate, it simply “expands” and “stretches” as it travels, giving you the “dissipating effect” The shape of the lens of the flashlight also has an effect. This lens which generally is a concave lens then distributes the light particles in a much more larger area, therefore it can hit more objects (therefore you can see more things!!!). Light never stops, unless it hits something (a particle) or it enters a black hole.

    I agree with some people here that the sky is dark because our vision organ(the eyes) can only perceive a tiny portion of the electromagnetic spectrum, “Visible light”. The other light wavelengths are either to long or to short for us to see (unlike some animals like snakes, which can see UV light!).

    Hope I helped!

  14. according to me,,,there must be not obstructions like dust or any particle in the light’s way in universe to which it could hit and dispatch its colours……moreover,,,,may be the wavelenght of THE BLACK LIGHT which we can see in space be more or less than human eye could see..

  15. shweta pandey wrote:
    according to me,,,there must be not obstructions like dust or any particle in the light’s way in universe to which it could hit and dispatch its colours……moreover,,,,may be the wavelenght of THE BLACK LIGHT which we can see in space be more or less than human eye could see..

    Okay I really have no idea what this means, but my best response is that light wouldn’t need to hit anything because it would be the colour of the star it came from and that “black light” is just weak ultra violet light.

  16. Maybe the universe isn’t dark. The reason we think it is dark is because we are so close to the sun, the ambient light in the universe is dark compared to the sun’s light during the day. The human eye is accustomed to the sun’s light, so it isn’t good at detecting light from distant stars. Just because we can’t see well doesn’t mean things are dark. The night sky looks pretty bright through a good telescope.

  17. idkmaybe wrote:
    Maybe the universe isn’t dark. The reason we think it is dark is because we are so close to the sun, the ambient light in the universe is dark compared to the sun’s light during the day. The human eye is accustomed to the sun’s light, so it isn’t good at detecting light from distant stars. Just because we can’t see well doesn’t mean things are dark. The night sky looks pretty bright through a good telescope.

    Actually that’s exactly what it means since we describe things as they would appear to humans. If we could see things like microwaves and infrared naturally than I’m sure it would be quite bright, but subjectively when you look up at night its dark.

    You wouldn’t say for example the universe is actually bright, for cats and bumble bees.

  18. Thanks to most of your retarded answers I feel like a dam genius right about now! Man….some u peeps dum as hell!!!!

  19. If you are using an ordinary tnutsgen filament lamp (preferably with a clear glass bulb) then a 150watt bulb will put out around 15watts of light in the visible range, a glass magnifying glass will not pass much infra-red so you really are comparing about 15 watts from this bulb with what you can get from sunlight(in the visible range) this is more than 800W per square metre.With a small glass, say 5cm diameter, you could focus about 1.5Watts power to a very small spot using sunlight (it comes in almost parallel from a very distant source).To get to half a kW per square meter at your magnifying glass you need to be much less than 5cms away from the filament of the 150Watt bulb and you can’t focus the filament image down to a spot at that range.

  20. I believe the night sky is dark because it is free of dust. You can only see light if(or when) it hits an object. Light cannot illuminate an object it cannot touch(hit).

  21. Having been to a high altitude (sleeping at 14000 ft), I would say that it is likely that the atmosphere itself is what causes the sky to be dark at night. When one camps at such a high altitude (such as on Mt. Kenya), you can see a lot more of the stars and it actually appears quite bright even when the moon is down. Thus, by extrapolation, I would imagine that just inside of our atmosphere, looking into the night sky, it would appear even brighter, perhaps even to the level that the “paradox” suggests.

  22. Thank you always for your reading materials.
    I’m Korean(S.K). Thus, this has been helpful for me to learn English properly.
    I’d like to get your posting whenever there are new comments……

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