Questions tagged [astronomy]

For questions related to planets, moons, stars and other celestial objects, and their motion on the sky.

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3 votes
1 answer
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Calculating the conjunction of more than two moons

I've been trying to calculate the period between the conjunction of all of the moons which my planet has. They are five minor moons with orbital periods ranging from 0.5 to 1.3 earth days, and one ...
5 votes
2 answers
170 views

What are the orbital characteristics of my double-planet system?

I'm trying to figure out the orbital characteristics of a double-planet system, kind of like Pluto and Charon, but much more equal in size. One planet is pretty much a perfect copy of Earth and the ...
13 votes
6 answers
4k views

A solar system where a planet is in the center?

Is a solar system where the center is a planet possible? Where would the heat on it and its moons come from? Would life of any kind even be possible? Would everything be pitch-black, or would some ...
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4 votes
1 answer
124 views

What would it look like from the ground if a rogue star approached Earth?

I imagine it would start as a new star, then get slowly bigger and brighter over the course of years. I'm wondering what color it would be, how it would affect the day/night cycle etc.
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2 votes
3 answers
288 views

Calendar-Worthy Events on a no-axial spin distant future Earth

The Question Let's try this again. Again. One concise question: "What significant and regular calendar-worthy events would either nomadic or stationary humans perceive on a distant future Earth ...
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-2 votes
3 answers
193 views

What would be the biggest threat if gravity stopped? [closed]

Suppose that the law of gravitation suddenly “stops working” one day, and all gravitational forces cease to exist. What would this mean for people on Earth? Could we survive for very long? If not, ...
7 votes
9 answers
833 views

How to make other stars visible to the naked eye in the day sky

In my world each person has the ability to call upon the power of a star; using it to further whatever end they’d want—i.e. using the sun’s energy to power a spell. However, they can ONLY call upon ...
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16 votes
6 answers
2k views

Viability of a mega star system

So my story hinges largely upon a precursor type race centered around a single star system that went extinct tens of thousands of years prior to the modern day. Obviously, the most common way to go ...
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6 votes
3 answers
203 views

Black holes: Can something that has fallen through the even horizon be recovered if the black hole evaporates quickly enough?

From puppetsock's reply to Is it possible to build a black hole (kugelblitz) gun?, it seems like a black hole of 228 tonnes evaporate after just 1 second. And the lifetime of a black hole in general ...
4 votes
1 answer
258 views

What would happen to a world with three moons?

The world I’m building is approximately 1/3 of the size of earth and it has 3 moons orbiting it. The orbits are all different but occasionally they have either a full moon or a new moon on the same ...
4 votes
0 answers
47 views

What could cause uneven seasons? [duplicate]

A world's seasons have different lengths. Winter lasts for 33% of the year, Spring and Fall for 25%, and Summer for only 17%. On the other hemisphere, it is the inverse. Is there any scientific ...
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2 votes
2 answers
539 views

How would day and night look like on a planet that orbits two suns? [duplicate]

I'm writing a fantasy story set in a p-type circumbinary system and I'd like to know how this would affect day and night, when the suns and moon would be visible, and the climate and seasons on the ...
28 votes
6 answers
5k views

Exactly how far apart are nearby stars from one another? [duplicate]

I am working on a hard(ish) science fiction space opera story, and I would like to get a good handle on distances between stars so that I can calculate appropriate travel times. There are a lot of ...
1 vote
1 answer
90 views

How big would the "Eclipse Region" of the given planet be?

In the project I am currently working on, I am making a world in a binary orbit with another similarly-sized planet. The two planets, which I have so far been referring to as Artemis and Apollo (...
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34 votes
13 answers
4k views

Finding Earth on a star-map

One day, I am randomly teleported to somewhere else where I meet some aliens. These aliens are very technologically advanced and after figuring out communication, we establish a rapport. The aliens, ...
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9 votes
5 answers
1k views

What locations in a galaxy would be best for stone carvings to remain undamaged or worn down for as long as possible?

I want a species of alien to leave their mark throughout the galaxy with stone carvings and temples. Taking influence from ancient religious stone carvings and decoratively sculptured temples carved ...
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7 votes
1 answer
321 views

Three Moons and Simultaneous Full Moons?

In my story's world, the planet is roughly Earthlike in terms of size but it has three moons. I have written in something called "brightnight", when all three moons are full at the same time ...
24 votes
8 answers
4k views

Can the Little Prince's planet actually exist in our universe?

This is a drawing by my daughter which inspired one of the elements in my story/world: The perspective is a little bit mixed here (certainly I don't have a 15 meter-high volcano in this world), but ...
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4 votes
4 answers
186 views

What if Earth's core became a planet of its own?

Would the Earth's core start expanding and release its heat? Would some of the metal(iron-nickel) evaporate due to boiling point temperatures and no pressure anymore? Would it affect the orbits of ...
4 votes
1 answer
137 views

What impact would a white dwarf-neutron star collision have on a civilization on a planet orbiting the white dwarf?

An advanced civilization lives on an Earth-like planet orbiting a white dwarf. Their star is on a collision course with a neutron star. I imagine this collision will cause a supernova, which will ...
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3 votes
2 answers
71 views

Tidally locked time keeping 2 [duplicate]

I have done some research and so much contradict one another or I simply fail to understand. Can a moon be used as accurate time keeping and is it possible for it to revolve around the planet once an ...
9 votes
4 answers
2k views

Do seasons occur on a tidally-locked planet?

I have done some research and so much contradict one another or I simply fail to understand. Do seasons occur on a tidally locked planet that isn't tilted on its axis?
4 votes
5 answers
698 views

An alternative way to rotate or in this case rolltate

As far as we know Earth and every other planet in the solar system rotate around their axes. Whether it be Uranus which rotates on its side or Mercury which rotates perfectly straight, all planets ...
6 votes
1 answer
299 views

I can't seem to find correct starbuilding equations that work together anywhere and am generally confused. Which ones do you use?

So far I've been using Artifexian's How To Build A Star YouTube video. The problem with this video is that it's quite old and thus outdated. The things I've noticed to be particularly weird are the ...
7 votes
4 answers
730 views

Is there a plausible way to have a Gas Giant with two or more earth to mars sized moons orbiting it in the Habitable zone?

A hypothetical scenario I'm batting around in my head is a Habitable Gas Giant system consisting of a roughly Saturn sized body orbiting a sun like star at a comfy goldilocks zone distance. Orbiting ...
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4 votes
2 answers
253 views

What would the sky view be like of a final stage massive merged galaxy?

What will be the view of the sky and the distances between stars, living on a planet or in a habitat in a super galaxy that has merged with all its nearby galaxies in its cluster, at a time in the ...
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5 votes
1 answer
266 views

Sunrise and Sunset In a Ternary/Trinary Star System

I have looked around for some time attempting to find a post that could help me answer the question I have, but I've come up short. I'm attempting to visualize in greater detail what my planet would ...
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7 votes
2 answers
307 views

Roughly how long could an 'Oumuamua type object get?

Roughly how long could an 'Oumuamua type object get if created naturally or if created artificially using fused rock? What would be the limiting factor governing the length of such objects? Oumaumau ...
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18 votes
19 answers
4k views

How could a spaceship, because of mechanical issues, crash-land on a planet they weren't intending on travelling to? [closed]

Apologize in advance if this sounds too much like a story-related question, but I'll try and limit it to logistics-only as much as possible. I have a spaceship that's travelling to a colony planet ...
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7 votes
1 answer
318 views

How to Calculate Apparent Magnitude/Brightness of Planets from Within the same Solar System

I'd like to be able to determine the appearance of the night sky from an Earth-like planet, in a solar system with multiple other planets, moons, and other bodies. Here on Earth, we can directly ...
6 votes
1 answer
254 views

What, visually, would a hole bored in the moon look like?

If you took a giant drill (~one hundred meter circumference) and bored down two kilometers into the moon, what would it look like (assuming the lighting was good)? Is there a gradient, or is it a ...
0 votes
1 answer
111 views

What would have happen to the Solar system if we were to mine a planet away [closed]

So the idea is to slowly mine a planet away , one like Mercury or Venus or Mars. Doesn't matter why or how. Only one of these planets would be removed. How the Solar system would react? Earth will ...
1 vote
1 answer
109 views

All planets and stars flat, how to bring day and night effect?

In a scenario in which all heavenly bodies are flat including earth. How to bring the effect of day and night effect like now i.e when day in japan and night in USA . Considering nobody can live ...
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16 votes
12 answers
598 views

What biological trait could make (certain members of) an insectoid species good at astronomy?

This is a science fiction intelligent alien biology question. I'm imagining a race of large (around 2m in height) insect-like species on a distant planet who discovered astronomy VERY late in their ...
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10 votes
3 answers
532 views

What would happen to a gas giant during a supernova?

Fairly straightforward question. Imagine a gas giant planet, like the size of Jupiter, in orbit around a massive star. The star goes supernova. What happens to the planet? Is the energy of the ...
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10 votes
1 answer
250 views

Is it possible to introduce life to a planet via preserved organism?

The dominant religion on my world (created by a race of dragon-like humanoids) believes that their species originates from an ancient being that sacrificed itself to defeat a great evil at the center ...
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6 votes
2 answers
356 views

What does a gas giant close to a red dwarf look like?

In my setting, there's a gas giant orbiting in the habitable zone of a red dwarf (for specificity, its radius is about half Jupiter's, and it's 0.35 AU from 61 Cygni B. Ignore the effect of the other ...
5 votes
3 answers
222 views

Constructing a doomsday machine by manipulating the Higgs Field?

I've been working on a sci-fi series set about 1000 years in our future. The discovery of an alien threat leads the ruling government to conceive of a doomsday machine, which they hope will be so ...
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0 votes
3 answers
833 views

What would happen if all stars disappeared?

I'm imagining a hypothetical scenario based on the Big Rip theory of the end of the universe (https://en.wikipedia.org/wiki/Big_Rip), where eventually the expansion of the universe causes everything ...
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9 votes
16 answers
988 views

How can I discourage parents from exploiting celestial events?

The moon has an effect on the mana content of an individual. During high tides, a person's mana increases and becomes more powerful. This is the time in which more powerful spells can usually be ...
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31 votes
14 answers
8k views

In a world without stars, how would travelers navigate at night?

On Earth, sailors would navigate the oceans at night by using the stars as guides; since there are no landmarks in the ocean like there are on land (save for the occasional island), that's pretty much ...
3 votes
1 answer
99 views

Ideal sun type and corresponding effects for a terrestrial planet with 256 days in a year?

The planet has 256 days in a year, split up into eight months, each with 32 days. My planet is a bit smaller than Earth: Think, enough space for the continents of Earth’s western hemisphere and the ...
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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 ...
5 votes
1 answer
918 views

Software for creating a 3D planet [duplicate]

(Sorry for my English, it's not my native language. I use Google translate.) I am looking for one or more software programs to create a sphere in 3D with longitudes, latitudes, etc. I want to be able ...
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6 votes
2 answers
208 views

How might an exoplanet have a highly radioactive atmosphere?

The exoplanet in question is Proxima Centauri b. How might the mid-to-upper-level atmosphere of that planet be dangerously radioactive and full of airborne nuclear reagents, without it being the ...
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28 votes
17 answers
8k views

Is there any conceivable way to "turn off" a star?

In my world, a group of "lamplighters" seek to turn off unused stars to conserve the energy for later use. This serves a few purposes, but mainly: It delays the heat-death of the Universe to some ...
6 votes
2 answers
224 views

Binary World Mechanics

I’m trying to develop a realistic system with a limited understanding of astrodynamics. Is it possible to have two binary worlds capable of sustaining atmosphere and complex life orbiting one another ...
3 votes
2 answers
168 views

How well would a planet in orbit of a star above the Galactic bulge see?

I am making a story of a species who lives on a planet several light-years above the Galactic Bulge. With advanced technology, how much could they see from their vantage point? Could they carry out ...
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1 vote
3 answers
80 views

Can velocity drift be used to calculate a radio wave source's distance from Earth?

If you're studying radio signals from Earth, is it possible to calculate whether a radio source is 'near' as in near Earth or 'very far away' as in somewhere far out in space from velocity, or ...
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5 votes
4 answers
366 views

Is a "Partial" Black-Hole Possible?

Black holes are created by the gravitational collapse of massive stars. But in theory, black holes can also be created by any mass at all that is confined within a small enough volume of space, ...
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