Olbers' paradox: why is the night sky dark?

Easy - because the darkness is a function of time, as explained in one of the masterpieces on the subject published in 1991.

Interstellar dust blocks some light. Plus, the stars that are billions of light years away are red shifted, and the farthest stars are super red shifted to where humans can't see the light.

to see the current sky above you (or at any other time)

I pondered this as a little girl. My science teacher told me I was overthinking it.

The sky is dark where it contains nothing. When there is nothing, there is nothing to reflect the light. Light can only be seen when it hits something. We see stars because that light is hitting our retina.

But if the universe is also expanding, doesn’t that mean the laws that may never reach us?

You can only see light when it illuminates mass... when mass is small it's invisible to light, still there but unseen!

Another way to think of the dark. When we look at the night sky we see a lot of dark… but there are stars there… and their photons do reach Earth. But our human eyes can not pick up these photons. But train a telescope on that same area and the photons are registered. Look at this photo of the Andromeda galaxy… which our eyes might pick up as one dot of light in the dark sky… This galaxy contains trillions of stars… and check out all the stars that surround the galaxy… our human eyes can’t pick up these photons photons from these stars but they are reaching the earth. When our eyes don’t pick up photons, we see dark. Astronomers out there… feel free to set this neophyte astrophotographer straight.

Olber's paradox posits that if the universe is infinite and every point contains a star, then the night sky should be as bright as a thousand suns due to the reflection of starlight. Yet, we observe darkness at night, suggesting either the universe is not infinite or there are mechanisms reducing light visibility.

What a bullshit, useless paradox. There is no paradox. 1. There are trillions, perhaps quadrillions, of galaxies. Every galaxy has a black hole. No matter how many stars there are or how bright they are, those regions will always remain dark. 2. There are trillions of times more planets that do not emit light, and they block light coming from stars behind them. 3. There are even more gas clouds in nebulae and throughout the universe. Then there is the massive cosmic web, which is mostly dark, emits no light, and blocks light coming from behind it. 4. Inverse-square law The intensity of light decreases as: I ∝ 1/r² where r is the distance from the source. If a star is 10 times farther away, its light is 100 times dimmer. At sufficiently large distances, the number of photons reaching Earth becomes so small that the star becomes undetectable with any practical telescope. 5. Earth's atmosphere Even after light reaches Earth, it is further weakened by: Rayleigh scattering by air molecules. Mie scattering by dust, smoke, aerosols, and water droplets. Absorption by atmospheric gases such as water vapor, ozone, oxygen, and carbon dioxide. Clouds, which can block or scatter much of the incoming light. Only someone who is totally ignorant, or desperately looking for any excuse to justify the Big Bang and cosmic expansion, would believe that Olbers' paradox is true and therefore the universe must not be infinite.

BS. If you have a telescope or even binoculars you can look almost anywhere and see more stars. The sky is dark because the light is too limited for our eyes to see it. Remember your pupils are less than a 1/4 inch wide. Telescopes gather 1000's of times more light.

Big bang theory means all stars started in the same place, this theory suggests that all thoughs stars where form far away and the light travels back to us, but if we all started in the same place the light should have already been here the whole time as the universe expanded.

So 65 million years ago when dinosaurs walk the earth it was darker at night than it is now

nah....a malign darkness is eating the universe.

Nonsense. The night sky is only dark from the earth because of our atmosphere. Exit our atmosphere and this is what you see:

Not accurate. Light is bent around stats and is creating lens effect this scattering light not at all in linear format also there is mass in the universe that is like planets and asteroids that blocks light out. On a scale such as the galaxy it balances out to be such as it is

Mandelbrot offered a new explanation of Olbers' paradox (the "dark night sky" riddle). He postulated that if the stars in the universe were fractally distributed, it would not be necessary to rely on the Big Bang theory to explain the paradox.

@grok arnt there dust particles that make the universe dark? What other theories are out there except expansion?

The night sky is dark because the universe has a finite age and is constantly expanding. If the universe were infinitely old, infinitely large, and unchanging, every line of sight from Earth would eventually hit the surface of a star. This means the night sky would be as bright as the surface of the Sun. This contradiction is known as Olbers' Paradox.🪐

Wrong, the distance between stars is incredibly vast and the light we see are from stars who's light is not obscured by gas nebula or dark matter.

Imagine you’re standing in a giant room full of tiny flashlights. But this room isn’t staying the same size. It’s getting bigger and bigger all the time, like a balloon someone is blowing up really slowly. As the room grows, the flashlights get farther and farther apart. The light from the far-away ones has to travel a longer and longer distance. The light itself gets stretched and weaker while it’s traveling. So even if there are lots of flashlights, the ones that are really far away look dimmer and dimmer, and some of their light never reaches you at all because the room is stretching faster than the light can catch up. That’s why, when you look around, you still see mostly dark space between the little points of light. The growing room is a big reason the night sky stays dark.

Some galaxies are moving away from each other faster than the speed of light.

光が減速する或いは消失する説。

Fun fact- trillions of years from now, cosmic expansion will push distant galaxies so far away that their light can no longer reach us. At that unimaginable timescale, the night sky would indeed look empty- completely dark void.

Craziness with amazingness

What an amazing fact!!!!!

This is the dumbest thing ever. They can claim that they know what’s happening since the “beginning” of time and claim that light just hasn’t arrived yet but at the same time, haven’t explore 90%+ of the Amazon and 95%+ of our oceans. Jesus is God

The universe will always be dark because of the expansion rate

Fantastic breakdown of the paradox. I disagree with the the conclusion though.

This would only be true if the universe were infinite in size and infinite in age and if there had always been stars from infinitely long ago. But it isn’t infinitely old.

I guessed and I was right. I didn't know for sure tho. Just an idea that it had something to do with the light not getting here yet. Edgar was a bitch btw.

because the universe had a beginning. otherwise the night sky would be filled with light

Do we really need science to explain why the sky is black at night. The world is fucked

Literally all fake if you believe the Big Bang is real.