Perhaps their planet is on the inside of a giant Dyson sphere that was created by an ancient civilization.

This would be a vast solid shell that surrounds their entire solar system, the inside of which is covered with solar panels in order to collect as near as possible to 100% of the energy output of their sun. Naturally, this would block their view of the rest of the galaxy as well.

As for why the ancient civilization who built it left this one planet on the inside, that's up to you to decide. Maybe they saw that it had some life forms that might potentially develop intelligence some day and didn't want to just kill them off, so they left them where they were, while dismantling all the rest of the planets in the system to build the sphere?

One possibility is for the surface of the planet to be covered in highly luminous matter. Perhaps all the surface is an interconnected network of bioluminescent life.

There is no moon (assumed because you make no mention) and the high levels of light pollution at night will blot the stars out.

You could combine with a naturally hazy atmosphere and cloud cover to a) further blot the stars and b) reflect all that light pollution back to the surface, further brightening it at night.

Normal urban terrestrial light pollution (before and during the great 2003 Northeast Blackout) to give you an idea:

It is never night.

https://www.tripsavvy.com/midnight-sun-in-scandinavia-1626397

Your people live on the north pole of a tidally locked planet. Like the countries near the north pole on our planet, in summer the sun never sets. It is always summer for your people.

Why do they only live near the pole? Maybe it is hot farther south. Maybe there are scratchy monsters. Maybe there is no land to live on.

Maybe they are afraid of the dark.

The laziest answer is to just wait a while. If you wait an incomprehensibly-long while, eventually the expansion of the universe will move all currently near-by light generating bodies outside of our visual distance.

In other words, civilizations in the far-future may never realize that anything other than their own sun exists, because nothing else is close enough to interact with anymore. This video has a nice overview:

https://www.youtube.com/watch?v=Qg4vb-KH5F4

there are many ways. especially if it's just you don't see the stars.

there could be a constant storm like on Jupiter and in 'All Summer In a Day' by Ray Bradbury.

Venus has an atmosphere made up mainly of carbon dioxide, and thick clouds of sulfuric acid completely cover the planet.

basically, clouds covering the entire planet would do the trick.

'light pollution' would also make it so the stars can't be seen because the ground is so bright.
Night Sky in Las Vegas Which is always full of light especially at night

vs the Idaho dark sky preserve

Is it possible for a planet in our part of the galaxy to have a night without stars?

It depends on what you mean by "our part" of the galaxy. If you point yourself in the direction of Sagittarius and travel a mere 2600 light years you will find yourself smack in the middle of the Great Rift, which is the dark patch you see covering the Milky Way.

https://earthsky.org/clusters-nebulae-galaxies/the-great-rift-in-the-milky-way

This is an area where new stars are formed, but obviously the dust is thick enough that we cannot see through it in the visible spectrum. It seems plausible that there could be star systems in that large area where the dust is thick enough that no other star is visible.

Note that the "thick" dust is by Earth surface standards extremely dilute and would be considered a high-quality vacuum. It's only the fact that there are light years of the stuff that make it hard to see through.

It is the basis for a society that develops into the modern age without an interest in outer space.

You might wish to research how the "space cloud" and "planet that doesn't know about space" tropes have been done before. https://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceClouds and https://hitchhikers.fandom.com/wiki/Krikkit may be useful.

The sun takes up about half a degree in Earth's sky. Stars are less than one ten thousandths of that. If atmospheric blurring were to blur a star one hundredth of a degree, their light would be spread over an area hundreds of times larger, making them practically invisible, while the effect on the sun will be minuscule.

HG Wells had a valley populated by blind people. They had no concept of daylight, so slept in the warmth(day) and worked in the cold(night)

Because the 'hero' couldn't see at night, he was less capable than any of them.

I see that someone commented about this answer not addressing the question - sorry, I'm new here, and I am realising that answers need considerable amplification, so let me add some more.

the question says
I'm looking for some kind of natural phenomena that would hide the stars, but allow the sun to rise and fall as normal. The atmosphere and day/night cycles should be unaffected.
It is the basis for a society that develops into the modern age without an interest in outer space,

So - a natural phenomenon would be blindness - the absence of sight. As can be demonstrated, or researched endlessly, blind people can carry out normal life - more so where adaptations are made, such as alarms to indicate when fluid in a cup, say, has reached within a given distance of the top. Or lets move further to travel. A society evolved as blind would place indicators at the edges of pathways, and tactile markers to indicate direction. If you can feel it, they can deal with it. This includes edge tools, and the capacity to produce more advanced mechanisms and more advanced means of travel such as boats.

Now - specifically, if you haven't seen the stars, then you have no notion of there being 'anything' out there.
I referenced HG Wells story because he does such a good job of describing the adaptations the inhabitants of this world adopt, whilst leaving them as a potentially advanced society - as may be needed by a world builder.

I submit that this answer fits both parts of the question - it explains and allows sunrise and fall, atmosphere and daylight. It also provides the means for a 'modern age' society' to arise and function.

It may not be what the OP (or commentator) expected, but it does fit the question.

http://www.online-literature.com/wellshg/3/

It's part of a rogue solar system ejected from any galaxy, somewhere in the middle of a large intergalactic void.

No stars would be visible until the inhabitants developed sufficiently powerful telescopes to be able to see the faint light of distant galaxies.

The people have eyes that only see sharp nearby. Everything is blurry to them on (very) long distance. It would not be too much of a disadvantage in normal life, but it would prevent them from seeing stars. Only after they develop reliable lenses, they would discover that stars exist.

The sun is a star, but I know what you mean. Here are some other options:

• Multiple suns (such as Asimov's "Nightfall")


• One sun, and many moons


• Large amounts of very white (or reflective) dust, which reflects sunlight around the atmosphere.


• Underground or underwater societies.


• Regular volcanic eruptions causing volcanic ash in the atmosphere (or anything else in the atmosphere)


• Monsters that come out at sunset


• taboo/superstition/religion


• Your planet might be near a black hole, causing gravitational lensing, an accretion disk, unusually high speed orbits, and jets coming from the poles.

I don't know if that counts or not as 'affecting/messing with atmosphere', but I've decided to reply anyway.

There's a layer of gas in the atmosphere that diffuses the light.

Light is still capable of passing, but it is randomly diffused before getting into the surface of the planet. The day would still be very well illuminated, but they wouldn't see the sun itself: they wouldn't see a bright ball up in the sky as the source of such illumination. As for the night, no stars, and darkness.

If there's a moon, the same thing from the day will happen: one won't be able to see moon itself, and a far lower intensity light reaches the surface, faintly illuminating the surface.

There could be intelligent life living under the ice on Enceladus right now. The thick ice would prevent them seeing stars.

Similarly, the habitable zone of your planet might be entirely underground.

Most of the answers so far seem to be ignoring the requirements that there be sunset or that the atmosphere behave differently.

A large dust cloud surrounding the solar system seems like the most reasonable way to achieve what you want since it doesn't directly affect anything within it. Its origin and how long it will persist are for you to work out.

But whatever solution you decide on, it sounds like the driving force in the story will be the reaction of those people to this new revelation. If so, make sure you come up with something new and don't appear to be copying how society reacted in Asimov's "Nightfall" (which used multiple suns to make total darkness almost impossible).

First idea: Their visual organs use a different method of "seeing".

You could make it so that your planet's inhabitants can't see, or some variant thereof.

I don't mean to say that the people are blind, but rather they have other organs that can "see" that would serve a similar purpose, but might seem magical to us. For example, if they were to inspect a sheet of paper, they might be able to easily detect tiny folds and creases in the paper, while the image on the sheet would be invisible to them.

To them, a pure-white rabbit on pure-white snow stands out clearly, whereas the pictures and text of a highway billboard sign are hidden to them, precisely because there is no "three-dimensional-ness" to distinguish the images from the board itself.

To them, the sky might look perfectly flat (or maybe even perfectly dome-shaped). As for their sun, they can either perceive it using another sense, or maybe its special case of being abnormally huge (compared to anything else they are familiar with) is enough to make them perceive it.

(If you can see those 3-D stereo images, you might understand what I'm getting at. When you succeed in seeing those images, you'll notice that you're perceiving three-dimensional shapes instead of colors. A starry sky wouldn't work too well in those 3-D stereo images, but a sun in the middle of the sky might.)

This could be similar to sonar; for example, a dolphin could detect a sheet of paper in the water no matter how dark or murky its surroundings -- however, it wouldn't be able to use sonar to perceive the picture drawn on the sheet of paper.

Second idea: Their visual organs perceive different wavelengths of light than ours do.

The inhabitants could have eyes (or similar organs), but see a different spectrum of light than us. And it just so happens that 99.9% of stars in the universe display light in the parts of the spectrum they can't see.

Their sun, however, is one of those 0.1% of stars that they can see.

You could even say that they evolved/adapted the ability to see their sun's light precisely because it comes from their own sun. (So why have a need to see other light?)

You could toy around with the idea that your society's planet could be in the L1 Lagrangian Point of a very large, non-reflective planet. As the society's planet orbits on its axis and brings the society to their own planet's dark side, they would see only the large dark planet in their sky, which would appear to them only as pitch black.

However, there is a significant window of time (particularly around sunrise and sunset) where they could still see the dark of night (including the stars) which is not covered by the large dark planet. If you're daring, you could make the dark planet a very non-dense, stretched out object that acts as a sort of visual shield around the dark side of the society's planet.

Sure, having such a large object in a non-spherical shape seems like a stretch, but maybe there are some special cases in this universe where that could happen. (After all, we already have Saturn, whose rings are quite visibly wider than Jupiter itself, but definitely not spherical.) Maybe the large, un-dense planet could have a large set of (seemingly solid) pitch-black rings. Or maybe it could have some other sort of shape anomaly more common than planetary rings, but that we're not familiar with simply because no planet in our own solar system happens to have it.

To put it another way, if Saturn didn't exist, we wouldn't have all those pretty artistic night-sky renderings with ringed planets (despite the fact that ringed planets do exist outside our solar system). So what other pretty astronomical sights are we not including in our artistic night-sky renderings, simply because they don't exist in our solar system, making us not aware of them?

In other words, just because something is planet-sized, doesn't necessarily mean it has to be shaped like a sphere.

Some ancient civilizations (here on Earth) thought that our sky was literally a dome. So maybe your society's planet could be in the L1 Lagrangian point of a non-light-reflecting partial dome.

Maybe they have vast swarms of firefly-like creatures that come out at night? They figure that they already know what stars are, since they are so obviously these creatures, that they never bothered to question it.

Perhaps the planet has some killer aurora borealis or something that drowns out the stars.

I personally liked the idea from The Three Body Problem which made it so that the intelligent species lived in a trinary system and would go through periods of heat so intense that all water would evaporate, and periods of cold such that the atmosphere would freeze. It would be really hard to get a civilization going when you have a near extinction event every millennia or so.

I also like the idea from Ringworld where these people lived on a failed Dyson Ring, and because the ring didn't have any way to mine metals, these stone-age folks couldn't get back up the technology ladder; they were stuck using stone and wood forever.

If you are on an isolated star in the middle of the Boötes Void (https://en.wikipedia.org/wiki/Boötes_void) you would not see a single star or galaxy with the naked eye.

BTW - have you ever read Iain M. Banks' Against A Dark Background?

Since many good physical explanations were given, let me provide some lateral thinking sort of answer.

The reason there are no stars is that they live in a giant simulated universe and there's not enough processing power and memory to simulate a full universe, just that solar system with just that one planet. So the sky is dark at night. The humans which are visiting are in fact those running the simulator.

I would suggest that their solar system is passing through a relatively very dense dust cloud in interstellar space, as others have suggested.

Their solar system would have been passing through it for hundreds of thousands or millions of years, long enough that the intelligent beings living there have no possible way to remember that their pre-intelligent ancestors ever saw stars in the sky.

The gravity of their star system has been pulling in the interstellar dust so that there is a clear cylinder of space pointing out of the dust cloud back the way they came. So that direction should point out toward intergalactic space with only a few stars in their galaxy and no globular star clusters, other galaxies, or intergalactic stars in the light of sight.

The in falling dust doesn't fall all the way to the star, however. At at certain distance range light from the star and particles in the stellar wind from the star hit most of the in falling particles and bounce them back out a bit before they fall back and are bounced out again. Thus there is a relatively dense shell of dust particles at the outer edge of the star system, dense enough to block all light that comes in through the clear cylinder of space and hide the relatively few stars that would have been visible through it.

The inhabited planet could be the only planet in its star system. But maybe there used to be two large planetoids or asteroids orbiting outside the orbit of the inhabited planet, worlds that collided and shattered into dust. Thus there could be an inner dust ring around the star outside the orbit of the planet, a dust ring that might also help to block out the light from the stars.

The atmosphere of the planet should be similar enough to Earth's for the natives, and maybe visiting earthlings, to breath without problems. But the atmosphere doesn't have to be identical to Earth's.

The atmosphere could be naturally foggier, or dustier, or something, than Earth's, thus making it slightly less transparent. And the intelligent natives might be greatly polluting their atmosphere and making it less transparent.

And if the planet has a slightly smaller surface gravity than Earth's, and a slightly higher atmospheric pressure at the surface than Earth's, the atmosphere will extend a bit higher than Earth's. Thus there were be more atmosphere for the light from the stars to pass through and be dimmed than on Earth.

It is possible that there are bioluminescent organisms on land or sea or perhaps in the air that emit a faint glow in most parts of that world. And if the atmosphere is foggier or cloudier at night that glow will be reflected down to the surface, further hiding the stars.

And of course in the cities of the intelligent natives and their suburbs artificial lighting may increase the light pollution as it does on Earth, hiding the stars even more.

The intelligent natives may depend mainly on echolocation and less on their vision, which might not be as good as human vision. And perhaps they have evolved a slightly more close range and less long range visual focus, for fine handiwork, making it slightly harder for them to see the stars.

Aquatic aliens, such as intelligent cephalopods or cetaceans, might have good vision in water but not so good in air and might not be able to see the stars.

And some combination of several of the above factors may prevent the aliens from seeing the stars, whether humans with possibly superior vision can see the stars from the alien planet or the stars are equally hidden from humans.

Some examples from our own solar system:

This society could very well come from our own solar system, our neighboring planets. If this society were to come from Venus, then the dense atmosphere would hide the night sky quite well. Titan also has a very thick atmosphere. And on Titan, I expect that even if the atmosphere had a transparency similar to Earth's, the reflected light from the numerous moons, as well as Jupiter would hide any starlight. The society would, however, know of things beyond their sky, being able to see the Jupiter as well as all the other moons...

The planet Saraksh described by Arkady and Boris Strugatsky in their book Prisoners of Power is close to what you are looking for.

Saraksh is notable for its monstrous refraction in the atmosphere. From the surface, it looks like the horizon is above the observer which makes the inhabitants of the planet think that they actually live inside a hollow cave in an endless piece of rock rather than on a round planet floating in space. The phenomenon of night and day change is explained by periodic changes in the clouds gathered in the middle of the "cave".

You have day/night cycle and despite not actually seeing the sun, you can possibly track its position by looking at the illuminated part of the cloudy sky.

The simplest way I can think of is to have a thicker atmosphere, and a warmer average temperature. The two combine to make a constant haze that in effect is like "cloudy bright" (photo term...) The sun is a bright spot in the sky. There are shadows, but they are diffuse.

The effect would be much like a smoggy night in L.A. during the 80's, but without the stink.

As a W.A.G. increasing the atmospheric pressure by about 10 psi, and the temperature by abouat 10 C would be sufficient.

A second possibility is to put them in a red dwarf system. The planet has to orbit close enough to the dim red star that it's tidally locked. This makes it always day. There is constant high altitude wind at high elevation from the center of the daylight side to the twilight zone. There is a constant surface wind from the dark side to the sunny side. The twilight zone should be constant storm from the cold darkside air running under the warm brightside air. Indeed, you may need to be close to the sub-stellar point to see any sky at all. Then you are looking at high noon.

I suspect that neither of these works as they never see a dark empty night sky.

Sidelight: Look at Asimov's novelette, "Nightfall" http://www.asimovreviews.net/Books/Book457.html