Questions tagged [astronomy]

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

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What would make an atmosphere a light olive green? [duplicate]

I am still working on a set of planets with realistic parameters, and the moon (0.623 M☾︎) of a planet (4.82 M⊕), around a star (0.631 M☉, K5.4V) has a very thin atmosphere, which gives it a faint ...
1 vote
1 answer
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could an equator-round elevator be possible for passing through rings of a planet to reach the moons?

I am developing a terrestrial, habitable planet with rings about the width of Uranus' rings. Not extremely thick, but still noticeable. I have heard that rings on planets would cause an inhabitable ...
4 votes
1 answer
76 views

What could make an exomoon sand-colored, other than just being covered in sand?

So I'm currently working on a set of scientifically plausible star systems, and I want to make one of the moons of a planet colored in patches of medium brown and pale brown dust/rock, but I can't ...
1 vote
4 answers
2k views

What if half a planet (not necessarily earth) was destroyed (not split)

Basically I want to know what would happen to a planet if half of it was destroyed using explosives. Does the answer depend on the size/gravity of the planet and what would be the result on the ...
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. ...
7 votes
7 answers
212 views

Locating rogue planet in deep space based on astronomical observations from its surface?

Assume that you have a Rogue Planet hurtling through deep space. Somehow, an alien civilization from, say, 1,000 ly away acquires astronomical data from this planet. This data is in the form of high ...
6 votes
2 answers
190 views

How plausible is my solar system?

I am currently working on a world orbiting around a red dwarf star (M0V to M2V, I haven't decided yet) and I need some help with designing the solar system. My original plan was having 4 planets ...
9 votes
7 answers
4k views

Can you have a very cold swamp?

In the research I have done, cold climates trend toward dry climates. I want to create a climate that circumvents this. I want to create a very cold climate with the average temperature hovering about ...
0 votes
1 answer
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Can an earth-like planet exist in a circumbinary orbit around two k-class stars?While also having up to two dozen other planets in circumbinary orbit?

I have a plot arc in mind, but it all hinges on the feasibility of an earth-like world existing in circumbinary orbit around two k-class (or g-class) stars. The looming danger in the story arc is that ...
2 votes
2 answers
86 views

What color would a neptune like planet have around an orange dwarf?

Let's say we have a Neptune like planet orbiting around a k5v orange dwarf star. The planet is about as massive as Uranus but its atmosphere contains a large amount of methane. Based on what I have ...
3 votes
3 answers
1k views

Stunted evolution on a tidally locked planet around a Red Dwarf?

I was exploring the trope of a non-evolutionary species, and then I realised that what makes species evolve are differences in their local environment. So I thought if there was a way for a planet to ...
2 votes
2 answers
112 views

How fast should my planet spin in order to be tidally locked?

I am designing a habitable planet with a diameter of 12.879 km. orbiting around a K5V orange dwarf star. Due to a number of planetery collisions during its creation, the planet ended up being tidally ...
2 votes
2 answers
105 views

Would it be realistically possible for an Earth-like planet to have a "hidden" moon?

I essentially just want the moon to always be in shadow of its planet so that from the surface of the planet it cannot be seen at any time of day - might "appear" as a black orb that blocks ...
1 vote
2 answers
176 views

Is this 'sky monster' astronomically possible?

The sky monster is a singular light in the skies of Droelep, a rather Earth-like planet in a system much like our solar system For part of the year, it moves from horizon to horizon on a smooth line, ...
4 votes
2 answers
461 views

How close could a creature longer than Jupiter get to Earth without destroying it?

So basic introduction: my world has things which naturally should never exist due to seemingly violating certain laws we deem as natural, for this, let's just call them "anomalies". Among ...
8 votes
4 answers
759 views

Possible reasons for a planet/celestial body not tidally locked to have a region in constant darkness?

Trying to form a mostly logical basis for a world that would have one region always in darkness while also having a day-night cycle. My first thought was to ask if a planet could have an axial tilt ...
17 votes
5 answers
3k views

Where could we add a new planet to the inner solar system?

Assume there was a super advanced alien race that for some reason, wanted to add a new planet, of lets say 1 Earth mass, into the Solar System. Where in the inner Solar System (The part of the solar ...
35 votes
8 answers
4k views

Proving a world is in our galaxy

A portal about 30ft in diameter appears on the surface of our present-day Earth. It appears for about 5 minutes each day before disappearing. Hesitantly, scientists go through it and discover a new ...
2 votes
0 answers
67 views

Other types of planetary systems? [closed]

I recently watched Artifexian’s video about other planetary systems, and I’d like to know more about those types mentioned and if there are any additional types I should know about. (I’ve heard that ...
125 votes
21 answers
24k views

What would make scientists realize they were on a flat world?

Scenario: While poking around in an alien ruin, scientists discover a gateway which offers instant transportation to an Earth-like world. The Observed World: The gateway leads to an area that is ...
4 votes
1 answer
374 views

How close the the star should i place my lava planet?

I am building a solar system with a k5v star at its center. Here are the some important stats for my star: Mass: 0.70 M Radius: 0.67 R Luminosity: 0.15 L Surface gravity (log g): 4.40cgs Temperature: ...
4 votes
1 answer
161 views

Can large stars have tidally locked worlds in their habitable zones?

I think the vast majority of space-enthusiasts has heard at some point that in order for a planet orbiting a red dwarf star to be habitable, it needs to be close enough to its parent star to sopport ...
20 votes
2 answers
3k views

What would the consequences be of a high number of solar systems being within close proximity to one another?

What would the consequences be of a high number of solar systems being within close proximity to one another? I'm mainly interested in the consequences for life on multiple planets. When I say 'close ...
3 votes
2 answers
119 views

How large would a chunk of ice have to be to do lasting harm if it were 'thrown' at Earth?

I'm working on a story involving life on Europa being upturned dramatically by contact from a probe sent from Earth. I know the chances of life, let alone intelligent life, are pretty slim on Europa, ...
3 votes
3 answers
167 views

Could a large chunk of Europa's ice crust be 'thrown' at Earth?

I'm working on a story involving life on Europa being upturned dramatically by contact from a probe sent from Earth. Found this community while researching, and have found a lot of great ideas. I know ...
3 votes
1 answer
481 views

Replacing the sun with an type A star (Fomalhaut) in a fantasy solar system where there is an habitable planet

Lets says there is a planet in the goldilocks zone of a type A star (luminosity of 16 and mass of 1.9 (like the star Fomalhaut)) How far would the type A star need to be from the planet and how would ...
3 votes
2 answers
151 views

What would be a good way to make a star map? [closed]

Recently, I was working on my fantasy world's zodiac, when I realized that I still hadn't worked out how the constellations were supposed to fit together in the night sky. This caused me a good deal ...
4 votes
1 answer
114 views

Would an Alderson Disk be possible around a White Dwarf Star?

I have seen the ideas of Alderson Disks around Sun-Like Stars. It would be utterly massive to say the least. Would an Alderson Disk be more 'possible' around a White Dwarf Star, how large would it be ...
8 votes
6 answers
410 views

Could an Irregular Orbit Cause Significantly Longer Seasons?

I have a fantasy world I'm making, with a planet and sun similar to our world, except the length of the seasons are significantly longer. Each of the seasons last two years, and the full seasonal ...
5 votes
2 answers
390 views

A planet with a naturally occurring margarita-like ocean

I imagined a hypothetical planet named after Bacchus (a nickname given to Dionysus, the Greek god of wine, ecstasy, parties, theatre, drama, comedy, tragedy, and spiritual madness). Its main ...
8 votes
5 answers
485 views

Galactic 'geographic' features, how could they impact galactic colonization efforts?

I have been wondering how galactic features could impact interstellar civilizations in the process of colonizing a galaxy (either andromeda or the milky way). According to this video these features, ...
8 votes
3 answers
213 views

How much more mass does Mars need to have in order to still be habitable today?

In an alternate timeline where Mars is the second Earth-like planet in our Solar System, the drive for colonizing it would perhaps have been much stronger. There would've been more resources spent ...
2 votes
0 answers
64 views

Questions about my binary planet system [closed]

I’ve recently designed a star system containing a habitable double planetary system, but I still have several questions to fill in I need answered. My binary planet is a Venus sized (mostly) Earth-...
9 votes
8 answers
2k views

Would it be possible to have 3 planets that could be colonised by humans in the same system?

I’m looking to create a situation where there are 3 habitable planets (or moons) in the same system, each with different inhospitable but habitable (by genetically modified humans or humans using ...
1 vote
2 answers
95 views

How would a moon's rings affect tides?

Let's say an Earth-like terrestrial planet has a rocky moon, and that moon has small rings, probably from pulling apart an asteroid, comet, or something similar. From my personal research, I know it's ...
5 votes
2 answers
137 views

Navigation and time-keeping on a slow spinning planet

I'm working on a story set on a planet that spins very slowly. Days and nights last years, and since it's either scorching hot or freezing cold, people, animals and all living beings must travel ...
2 votes
1 answer
110 views

What are the Celestial observations and mythology on a ringed planet? [closed]

I'm building a ringed world with it's rings composed of low albedo material to try and dampen the impact the rings have during night time (that is, trying so not every single night that the rings are ...
3 votes
3 answers
112 views

How slow and and how close could a rogue planet pass by the Solar System not to have catastrophic consequences on Earth Orbit?

This is part of a series of questions. Context: a friend of mine is writing a novel about a rogue planet around the mass of Mars passing by the solar system before continuing its journey in ...
4 votes
1 answer
152 views

How would I calculate the greenhouse effect based on atmospheric composition?

Problem: For a known, but hypothetical planet orbiting a celestial body, how would I calculate the surface temperature after greenhouse gases? What I know about the planet as given: Planetary ...
3 votes
3 answers
883 views

Could a planet without an orbiting moon still be habitable to human life in at least one small pocket? [closed]

No moon likely means no tides. Does this make a planet half water, half land, or similar divisions? Do freshwater and saltwater have separation? Or would it just be a planet like ours, with delineated ...
4 votes
2 answers
76 views

Seasons of an exomoon in a binary star systems

In my story, I have an superhabitable exomoon that is tidally locked to a gas giant (a planet similar to Saturn with the rings, but slightly smaller). This gas giant is in an s-type orbit of a binary ...
6 votes
1 answer
173 views

Largest possible biomass on any given exoplanet

Suppose you are the hypothetical architect of a new exoplanet, who's been handed the job to maximize this exoplanet's biomass. Given the current knowledge of life as it is, and thus leaving any sort ...
3 votes
1 answer
140 views

Is this a hycean world?

In the speculative astrobiology book Teeming universe by Christian Cline, there's a planet called Hurcelion. It's described as a hybrid of rocky and gas giant planets. Most of the life floats or flies ...
3 votes
2 answers
115 views

Length of months in Europa

Imagine billions of years have been passed and the Sun has been so big that the Earth is completely swallowed by it. Now the habitable zone reaches Europa, one of the moons of Jupiter. Let's assume ...
3 votes
1 answer
151 views

What kind of atmospheric composition would make the sky look green and still be breathable?

In my story scientists discovered a planet that look green from the telescope and they used a advanced starship to go there and the y found out that the planet is habitable with a breathable ...
4 votes
2 answers
296 views

What would happen if a neutron star approached the solar system?

Given its enormous eletromagnetic field and gravity( and probably gravitational waves would be very powerful) what would happen if a neutron star approached Earth? What if approached just by few light ...
5 votes
2 answers
100 views

Feasibility of multiple satellites around a planet inspired by Luyten B/Gliese 273b

I am writing a science fantasy book that takes place on the planet Luyt (inspired by Luyten B/Gliese 273b). Because the orbital period of the planet is about 18.6 days and I have chosen to make the ...
2 votes
2 answers
181 views

Could a molecular cloud turn the Sun into a killer star?

Let's say an unknown cloud enters the Solar System and begins manipulating the Sun, destabilizing the magnetic fields. Could it end up causing the Sun to emit gamma ray bursts to render the system ...
17 votes
4 answers
2k views

How do I determine when a planet is visible?

Recently, I was working on the various astronomies and astrologies of my fantasy world, when I had an interesting thought: “What if there was a planet that was so faint, people would be arguing if it ...
4 votes
4 answers
203 views

What would be the conditions to bring about an extremely mountainous planet

What would be the conditions of a planet for it to, over the years, form an extreme amount of mountains all across the planet. Not like a ball of spikes, just extremely mountainous. I still want this ...

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