Questions tagged [day-night]

For questions regarding the day-night cycle of a day on a world. Usually regarding the dark-light cycle.

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12 votes
9 answers
2k views

Possible explanations for abnormal day/night cycle?

This is my first question here, so any help would be greatly appreciated. I am trying to figure out how my world's day and night cycle works, or if something like what I'm hoping for is even possible. ...
4 votes
2 answers
39 views

How to prevent the effects on gravity, climate and day-night cycles on a "planet" with a surface area nth time as big as earth's?

In my story, one key feature is that the earth-like planet or habitat has a surface area of earth > 10 times. However, as it is inhabited by pre-industrial humans that might have been brought on it ...
9 votes
14 answers
3k views

Is it plausible for a world without an external universe to develop a year system?

I'm currently in the phase of planning a time system for my world and I am starting to run into logistical issues. My world essentially is an island in an endless ocean. No universe, no rotation of ...
6 votes
3 answers
785 views

What is a reasonable day length for a planet with 4 times earth radius?

The fictional planet has a mass of 18 times Earth's and four times earth's equatorial radiusreference. This gives it a gravitational acceleration of 11.02m/s^2 (1.29G) and an escape velocity of 23....
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5 votes
1 answer
169 views

How would short nights affect human life?

My world is a flat disc, with a sun orbiting around it, and a stationary moon in its center whose shadow simulates nighttime. Due to this, the central and outer regions experience a state of perpetual ...
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8 votes
6 answers
4k views

If Earth had a smaller radius, but was rotating at the same speed, would its day be shorter?

I want to make a hypothetical planet that is 26% the mass of earth, with 64% the radius. Because I want a relatively short day to keep temperatures more stable, but I don't want a super fast rotation ...
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4 votes
2 answers
73 views

Can an Earthlike planet orbiting a K-type star have longer days and extreme thunderstorms?

The planet orbits a K-type star. Basically same gravity as Earth's, with similar atmosphere. I'd like it to have a 30-hour day, plus in my characters' region, occasional very bad thunderstorms. Think ...
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0 votes
2 answers
96 views

How bright would these four stars look on the planet you're standing on right now?

Most of the numbers here have been plugged to me by someone you would find on both Reddit and the Speculative Evolution Forum. Imagine yourself standing on a planet in a quaternary solar system. The ...
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0 votes
1 answer
72 views

In this binary, how far would the secondary planet orbit the primary planet and still have its own day-night spin?

A scenario I've been exploring lately: Orbiting a binary of G0 stars (each one 105% as wide, 110% as massive and 126% as bright as our sun) from a distance of 2.065 AUs is a planetary binary. The ...
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4 votes
5 answers
234 views

Endless global night.. but an agreeable climate, how come?

How would my planet develop an acceptable climate, without a sun ? There is no (visible) sun, but the climate permits STP, and there are 1 or more luminous, rocky moons providing some light. Perhaps ...
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-2 votes
2 answers
186 views

Can owls, cats and others visual nocturnal animals see in moonless nights?

Im working in a moonless xeno planet and i want nocturnal creatures. I have animals that use smell, ear and touch, but im not sure about vision. I mean, animals and persons need a tiny bit of light ...
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2 votes
4 answers
173 views

Day/night in Aether

An extremely powerful wizard decided to create a new dimension as a birthday present for his wife, this dimension is composed of flying islands inhabited by fantastic plants and animals. The islands ...
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3 votes
3 answers
409 views

Climate on a slow spinning planet

I'm currently working on a story set in a planet whose rotation period lasts around 24 years (Earth years, or 8766 days). This planet orbits at more or less 0,75 AU from a K-type star, and the ...
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5 votes
4 answers
300 views

A Planet Approaching being a tidally locked planet

I am world-building an adventure for the Alien RPG. As a world approaches being tidally locked, and by this, I mean in the process of slowing down, but not stable. In such a world that no longer ...
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1 vote
1 answer
96 views

Would 6 Earths Separated by 60 Degrees Have Day-Night Cycles?

This picture is taken from one of Sean Raymond's Planet Planet articles, Cohorts of co-orbital planets. What the article doesn't explain, however, is the basis for the question. In a solar system in ...
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3 votes
2 answers
117 views

How would a planet's (human) life adapt to inconsistent night duration?

I realise this question is rather broad, so I'll do my best to narrow down what I'm looking for as much as possible. The big idea The full daylight cycle on this hypothetical planet is consistent in ...
6 votes
2 answers
221 views

If John Atkinson Grimshaw's Paintings were actually daylight, what kind of star would this "sun" be?

An Englishman by the name of John Atkinson Grimshaw was known only for his nocturnal paintings of the British landscape. I don't know about you, but his nocturnes have struck me as a bit...bright. ...
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0 votes
1 answer
1k views

What Would the Sky Look Like If the Sun Were a Different Color (And Still Half a Degree Wide)? [duplicate]

This question has been asked many, many, many times--what would the sky look like if the sun were a different color? But the mistake I keep seeing is that they used actual stars and imagined Earth as ...
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14 votes
5 answers
3k views

Could We See a Lagrange Giant in the Sky?

The "Lagrange giant" in the title refers to a gas giant that orbits its star in the same distance as Earth does. The alternative description is "Trojan planet" or, to be most ...
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4 votes
2 answers
262 views

How bright is night on a moon orbiting a gas giant?

I have an Earth-like moon tidally-locked to a gas giant that is Saturn-like but without rings. On the side facing the gas giant, how much brighter would nights appear when the gas giant is fully ...
5 votes
4 answers
360 views

What forms of life would be best adapted to living on a world with nine year long days?

Let us suppose that instead of the 24 hour cycle we currently enjoy on Earth between day and night, we instead lived on a planet with a day/night cycle that lasted a full 9 years. The noon of the day ...
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2 votes
1 answer
131 views

Life in the Temperate Zone of an Alternate Earth with an Axial Tilt of 42 Degrees--What Would the Seasons Be?

Suppose that in an alternate universe, Earth has an axial tilt not of 23.5 degrees, but 42. This means that from the equator, tropical climates with binary seasons (wet and dry) would persist from as ...
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4 votes
3 answers
430 views

Logistics of habitable moons orbiting a brown dwarf

Okay, so I've found some threads about the day/night cycle and seasons of habitable moons orbiting gas giants, but what if we replace the gas giant by a brown dwarf (i.e. the sub-stellar object class ...
4 votes
1 answer
179 views

What is the ideal day length for extreme weather?

This question is in reference to a previous question by TrEs-2b and SRM: I want to create a planet with a significantly longer day than Earth's. However, I was only able to find a question about a ...
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4 votes
2 answers
134 views

How could a planet with a long day-night cycle naturally regulate its temperatures to allow life?

So, my planet has (around) an Earth year long day-night cycle. How could its temperatures not reach extremes that would disallow life? Assume that everything is Earth like except for multiple moons (...
3 votes
2 answers
516 views

Temperatures of a planet with 1,000 Earth day long day-night cycle

My planet is Earth like in size (I can change it, if needed), however its day-night cycle is somewhere around 1,000 Earth days long. How hot would day get, and how cold would night get? Is it possible ...
1 vote
0 answers
105 views

How Bright Would the Sky on This Alternate Earth Be? The Sequel to "The 372-Day Calendar"

Long ago, I asked how far Earth would orbit the sun if one year lasts 372 days instead of 365 and how much it'd affect the overall brightness. What I got was that Earth with a 372-day calendar would ...
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1 vote
2 answers
256 views

How Bright Would Super Saturn's Rings Be in Our Sky?

It's not that long ago that we have found the "exoplanet" J1407b, notable for having a ring system 200 times the size of Saturn's. I airquote that term because, at a mass ten to forty times ...
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1 vote
1 answer
49 views

Animals, plants, and sleep cycles on a moon with a very long day-night cycle [closed]

Let’s say that this moon is about the size of Earth. Let’s say that our moon has a very long day-night cycle; about an Earth year. During night, would all plantlife die because of the lack of light? ...
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6 votes
8 answers
432 views

Could a planet with many moons see a different moon each night?

This is just an idea I have been toying with. Taking Earth as an example with 7 days in a week, my idea would that there would be 7 moons in orbit around the planet. They would not necessarily share ...
2 votes
0 answers
55 views

How long would daytime and nightime be on a planet with a 26 hours rotational period? [duplicate]

The basics about the planet in question: As the second planet in the star system, it's somewhat warmer than Earth is. The rotational period is 26 hours and the orbital period is 312 days which ...
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1 vote
2 answers
225 views

Would this sort of climate be possible on a tidally locked moon? [duplicate]

In the current fantasy novel I'm working on, I decided that I wanted to have a part of the planet where it was always daylight. After doing some research I learnt about the concept of tidally locked ...
10 votes
4 answers
2k views

What would days and nights look like on this cylindrical world?

This is yet another "literal worldbuilding" question, as in, building worlds. Inspired, in part, by this question. What if this world is a very long (effectively infinite) hollow cylindrical cavity ...
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19 votes
6 answers
3k views

I want ten Earth-years long day on my planet. Can I have it?

I need ten Earth years long day-night cycle on my planet. Hemera is a world I am creating as a setting for my story. Name comes from Greek deity - personification of Day. Needs of storytelling have ...
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3 votes
2 answers
58 views

Frequent Solar Eclipse Cycle and Its Effects [closed]

I’m trying to imagine a sci-fi/fantasy world in which a solar eclipse occurs roughly once every 3 or 4 days. The exact frequency can be arbitrary and varied, but it does need to occur often. I would ...
22 votes
6 answers
2k views

How do I calculate the hours of daylight on an arbitrary planet for a given day at a given latitude?

I want to be able to graph the change in daylight hours across the year for a given latitude, to get an idea of what kind of cycle in available daylight people at that latitude would live through and ...
5 votes
1 answer
261 views

Under which circumstances could a planet have two visible suns?

In the story I'm making, it is important that there are two suns in the sky, going at different rythms (maybe the planet orbits one of them each year, and the other each four years, for instance), and ...
2 votes
3 answers
142 views

Could a planet have a week long day and a week long night depending on the season?

Essentially I'm looking for a plausible way that a planet could have odd, extreme seasons. Basically I'm wondering how (or if) a planet could work that has a week long day during the summer and a week ...
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4 votes
2 answers
116 views

Alien Speices with extreme day/night cycle

I am creating this alien species and they live on three separate worlds blah blah, that doesn't matter right now. This one planet I have has a fairly long day-night cycle (I haven't decided on how ...
5 votes
2 answers
240 views

Creating "Sunfall" on the moon of a gas giant

I'm attempting to figure out the orbital physics of a system that has a habitable body that has intense periods of waxing and waning sunlight. I've come to the assumption that the best body for this ...
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7 votes
9 answers
2k views

Realistic ways a Planet or Large Moon could have Variable Day/Night periods

Hello I imagine this is a pretty straightforward question, perhaps already covered in another post, but I wanted to get extra perspectives and options for achieving this type of planet or moon. So ...
4 votes
1 answer
214 views

Days and Seasons via Daily Eclipses in a Flat World

While working on the cosmos of a flat world, I came upon the idea of using a dim sum rotating about an axis through the central pole (as described here) in order to accomplish days and seasons. The ...
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4 votes
2 answers
293 views

Sleeping in a world without night

I'm working on a game world where light (Lux) gives literal definition to all matter. Anything in complete shadow (Umbra) is without definition and completely amorphous. At the center of the world, ...
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7 votes
7 answers
369 views

Always night in one hemisphere. Is it viable?

I am building a world where one side of the planet has normal progression of day and night whereas in the other hemisphere it is always night. At first I had no idea how this could be possible in the ...
8 votes
2 answers
482 views

Nocturnal Photosynthesis

It's a basic fact that most plants need sunlight to generate growth. Sure, they also need water and nutrients, but their reliance on sunlight is the one sole thing that separates them from animals. ...
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3 votes
3 answers
286 views

How could I scientifically explain a world with day/night cycle only on the equator?

I'd like to build a world that has one pole where it's constantly day (all year long) and the weather is very hot, and one where it's constantly night (all year long) and the weather is freezing. I'd ...
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6 votes
7 answers
914 views

A planet of ice and fire

I had an idea for a planet which has very hot days, roughly 40 degrees C on average, and very cold nights, average -5 degrees. These figures are subject to change. Of course, there are places which ...
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5 votes
4 answers
484 views

Could a Stanford torus rotate on an additional axis to give it a diurnal cycle?

Suppose you have a regular old Stanford torus space station with a 'glass ceiling' rotating at 1.3 RPM. Put it in orbit around a star such that its axis of rotation intersects the star (in other words,...
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2 votes
1 answer
172 views

Seasons & days with steep axial tilt?

Given tilt of about 90deg (like Uranus), with day & year like Venus (day longer than year), orbiting a purple (brown) dwarf (not tidal locked). I'm having trouble getting "seasons" & day ...
2 votes
6 answers
260 views

Would separating people into 2 groups help the economy in any way?

Would splitting humans into two groups, those that work and live during the night, and those that work and live during the day, help the economy in any way? What would be other considerations of ...