Questions tagged [astronomy]

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

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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 ...
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4 votes
1 answer
97 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 ...
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3 votes
3 answers
867 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 ...
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4 votes
2 answers
59 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 ...
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3 votes
2 answers
92 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 ...
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3 votes
1 answer
111 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 ...
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4 votes
2 answers
243 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 ...
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5 votes
2 answers
76 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 ...
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2 votes
2 answers
175 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 ...
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3 votes
1 answer
107 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 ...
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17 votes
4 answers
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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 ...
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4 votes
4 answers
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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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3 votes
4 answers
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The plausibility of Rock comets and Molten Asteroids

If a stony asteroid get so close to it parent star that the siliceous rock would get hot enough to melt, What would happen? Would the rock turn straight into vapor and form a comet tail line like in ...
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4 votes
4 answers
173 views

What are the odds of a binary solar eclipse?

I'm currently creating my own binary star system which includes a circumbinary planet that has two moons. For simplicity's sake, the stars, planet, and moons are comparable in size to our own Sun, ...
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4 votes
2 answers
92 views

Is there any reason that justify or make seem more optimal to make sky observations for astronomical purposes on equinox and solstice?

In the setting I'm working on a giant mechanism opens on every equinox and solstice to record the sky and use the data for calculations that are required for the story plot. For astronomical reasons, ...
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0 votes
1 answer
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How do unnatural processes compare to natural geological processes in the formation of rocks & minerals? [closed]

As in an asteroid hitting a planet to make glass & other formations. Are these considered minerals? Can a crystal structure be formed?
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0 votes
1 answer
116 views

How would a "computer" be useful in a medieval world? [duplicate]

I am working on a story idea where a character in a medieval world develops a rudimentary computer. It is made of simple building blocks similar to the flip-flop and and/nor gates of digital logic. ...
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1 vote
2 answers
58 views

Life present on earth-like habitable exo-planet

Scientists are looking for an earth-like habitable exo planet. If an exo planet is earth-like (in terms of gravity, atmosphere, light, water etc.), then it must have gone through an evolution process (...
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7 votes
6 answers
498 views

How can a moon be always full (no other phases)?

I'm writing a system where the moon is always full from the perspective of the Earth-type planet--it does not go through phases. Short of the moon itself being luminous, what would it take for this to ...
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3 votes
1 answer
68 views

Where should I place my Earth-like planet within my binary system?

I am working on a RPG setting which requires my planet having a nearby flare star. I understand from reading through other, similar questions and from doing some research, that flare stars are ...
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  • 352
2 votes
2 answers
182 views

Days with a torus shaped Sun

What would day and night look like on Earth (or any habitable planet), if the sun was torus shaped, with the same circumference? And moreover, how much the Earth will be affected, if the sun was ...
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1 vote
1 answer
108 views

Two celestial bodies tidal locked - not with the sun

I tried to do my homework and actually thanks to this question and answer, I found myself to this site. But I just found more questions :) Basically the setting would be close to what Earth - Moon is, ...
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3 votes
1 answer
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How Far In Advance Could People See A 100-1500 Meter Earth Bound Impactor Before It Hit

How much advanced notice would we likely have in advance of an Earth bound impactor with a place of origin outside Earth's orbit (e.g. a meteor, asteroid, comet, space debris that doesn't rotate ...
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2 votes
1 answer
112 views

What Size and Likelihood Of An ET Impact Would Destroy A Small County Sized Region But Not Our Species?

Motivation The question is inspired by the astronomy journal preprint released publicly today, entitled: From impact refugees to deterritorialized states: foresighting extreme legal-policy cases in ...
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8 votes
2 answers
350 views

Time scale and mechanism to “realistically” remove Sol from the Milky Way

What is the fastest rate a star could be flung out of our galaxy and by what mechanism(s)? (i.e. from a gravity kick by a hypothetical passing hypervelocity black hole) Secondary question: how far ...
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18 votes
9 answers
6k views

How would people detect a 1 year time jump between star systems?

Scenario: A wormhole is created between Sol (earth) and a planet in Alpha Centauri. Travel through the wormhole appears instantaneous from the travelers perspective. However, the wormhole has a one ...
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4 votes
1 answer
234 views

Where can lithium be found in the Solar System?

My question is pretty straightforward, beside earth, what celestial bodies could hold exploitable quantities of lithium-7 and lithium-6? I understand that lithium is a scarce element in our universe. ...
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4 votes
1 answer
261 views

How big can a whirligig/planetcake get while still maintaining human-survivable gravity at its equator?

A whirligig/planetcake/whatever punny name you want for it is a super-sized planet (we're talking about Jupiter masses here, not Earth masses) that spins so quickly that it's shaped like a pancake (...
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3 votes
2 answers
356 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 ...
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6 votes
1 answer
89 views

Could a slow rotating planet be protected by another's body magnetosphere?

I'm working on a slow spinning planet whose rotation period lasts around 24 Earth-years (about 8766 days). It would be a rocky planet similar to the Earth in size and mass orbiting a K- or G-type star ...
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3 votes
3 answers
321 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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6 votes
1 answer
166 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 ...
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0 votes
1 answer
126 views

How large would Alpha Centauri AB be in the sky, when observed from exoplanet Proxima C?

Context: I am creating a hard science-fiction world set in the Alpha Centauri system. How large and bright would the binary star Alpha Centauri AB in the sky, when observed from an exoplanet (Proxima ...
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-1 votes
2 answers
65 views

Conditions for tilted gas giants [closed]

I have been working on further refining the solar system that would serve as the setting for my narrative project and in particular I'd like to settle one issue that's been on my mind. I have been ...
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0 votes
3 answers
233 views

Is a Habitable Planet With Three Suns and a Moon Realistic?

On this planet, which is mostly arid and dominated by large deserts and expansive steppes and savannahs, the sun rises once, and then two more times in the morning, and throughout the night an ...
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2 votes
2 answers
262 views

Stellar/planetary configuration to maximize number of solar eclipses

On Earth, the planet has a single moon and a single sun. And as long as the moon stays within a certain proximity of Earth (apparently, it's slowly drifting further away), a total eclipse occurs at a ...
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6 votes
3 answers
260 views

Through natural means, what could protect a rocky planet from intense x-rays from a black hole WITHOUT the expense of creating life?

I thought I had it. I thought I had finally found the solar system with enough light to produce hundreds if not thousands of Earths. I thought that a black hole 12 billion times more massive than our ...
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6 votes
6 answers
356 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 ...
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1 vote
3 answers
192 views

how do you freeze an ocean to get a desert planet?

So I'm in the middle of writing my desert planet, let's call it Thermos for now, and I'm having a bit of trouble balancing some aspects which I'll get to later. Thermos is an earth like planet with an ...
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2 votes
2 answers
112 views

Can an hourglass shaped planet exist, with core in the middle (small but dense) and crust at two other ends

Followup question would be whether life could exist in the surface area of the progressively smaller circles some distance away from the core.
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2 votes
1 answer
109 views

Does this F-star solar system make sense?

The setting for the narrative project me and my team are working on is a solar system with centred by an F-star 1.3 to 1.32 times more massive than the sun aged 2.5 to 3 Billion years. Here is how the ...
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3 votes
2 answers
786 views

Is it possible for a future civilization to concentrate the galaxies (or some of them) of the universe?

In the world I describe there is not much time left before the expansion of space takes its toll. Galaxies are already accelerating away from each other on a negatively curved spacetime. The expansion ...
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5 votes
2 answers
264 views

Effects of a larger value for the Gravitational Constant?

Assuming otherwise-identical physics, what would be the effects on stars and planets if the value of the Gravitational Constant was, for example, 100 times greater than in reality? In particular, how ...
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4 votes
1 answer
156 views

What would a Haumea-shaped Moon look like from Earth?

Basically what it says on the tin, I'm writing a fantasy world and I'm testing some exotic types of moons for this one. Then I came across Haumea, a dwarf planet located beyond Neptune. Quoting ...
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11 votes
1 answer
1k views

Trying to survive a passing neutron star by burrowing deep in the planet's crust?

Situation: My colony is threatened by a passing neutron star. It turns out this planet is part of a binary system and once every several hundred years it passes by a neutron star, which irradiates its ...
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  • 540
1 vote
2 answers
120 views

How advanced would a civilisation need to be to notice one of their system's planets is tidally locked?

Picture a tidally locked planet that is also the closest planet to the star (~0,17 AU from a star with a luminosity of ~1,5 times that of the Sun). The side of the planet that faces the star would ...
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5 votes
5 answers
298 views

Is there a way for a permanent Lunar eclipse, or another Object to always be in Earth's shadow?

I have a question regarding worldbuilding and haven't found a question like this yet, so I created an account and hope that someone can answer it :D As a starting point, imagine our real-life Sun, ...
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5 votes
1 answer
100 views

How close to a star can be a tidally locked planet so to have moderate temperature on its dark side? [closed]

So, imagine an atmosphere-less planet, tidally locked to a sun-like star. How close to the star can the planet be before its dark side becomes too hot? I imagine that at some point the rocks on its ...
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7 votes
5 answers
534 views

Measuring local orbital parameters with a smartphone from the surface of an unknown planet

My protagonist is stranded on an alien planet. Fortunately, along with ready supplies of food, shelter, water, electrical power, etc. she has a functioning high-end smartphone. She uses this ...
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6 votes
1 answer
99 views

Could a land mass reasonably exist where I want it on my earth-like binary planet? [closed]

I've been doing a lot of research lately on my binary planet system for the series I'm writing. Some details I've already worked out: The system's star is 0.6 solar masses, 0.8 solar radii and 0.3 ...
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