Questions tagged [astronomy]

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

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2 votes
2 answers
207 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 ...
1 vote
1 answer
140 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
104 views

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
118 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
354 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 ...
19 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
254 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. ...
4 votes
1 answer
273 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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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 ...
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6 votes
1 answer
104 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
408 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
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 ...
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2 votes
1 answer
143 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 ...
-1 votes
2 answers
71 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 ...
0 votes
3 answers
263 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
269 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 ...
6 votes
3 answers
267 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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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 ...
1 vote
3 answers
221 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
133 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.
2 votes
1 answer
124 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 ...
3 votes
2 answers
798 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 ...
5 votes
2 answers
283 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 ...
4 votes
1 answer
177 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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12 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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1 vote
2 answers
125 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 ...
5 votes
5 answers
327 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, ...
5 votes
1 answer
102 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
542 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
104 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 ...
2 votes
3 answers
130 views

What kind of ecosystem would naturally develop on a relatively large outer moon of a gas giant?

As far as I know, moons that orbit a gas planet from a greater distance are less likely to be tidally locked, more likely to have a retrograde rotation but tend to have unstable orbits and axial tilts....
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2 votes
1 answer
188 views

How Small Can a Planet be with 1G Gravity and Tectonics?

Without resorting to solid osmium inner cores that we couldn't give an origin story for, what's a cosmologically plausible lower bound of a planet's radius that also maintains 1G gravity and the sort ...
3 votes
3 answers
173 views

How would the reflection of sunlight change the day / night cycle of a binary planet system?

I am thinking of setting a story in a binary planet system, but am unsure what mechanics would be at play in regards to the reflection of light off of one planet and the day/night cycle. In this story,...
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5 votes
2 answers
157 views

Maps of star clusters

Inside star clusters, there are regions where stars are within 1 light year of each other. I wish to create a sci-fi setting in one of these regions. To start, I have tried to find maps/charts of ...
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3 votes
5 answers
148 views

Could a planet form from the remnants of a star and its solar system?

This is just a simple question, and I haven't thought all that well on it, but I think in terms of sci-fi and fantasy less tied to probable scenarios this could be quite possible. Imagine a free-...
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2 votes
2 answers
370 views

What would a neutron star look like up close to the human eye?

I suspect it would look something like the black hole Gargantua in Interstellar, but instead of a dark center, it would be glowing, like a star? It would still produce gravitational lensing and bend ...
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6 votes
2 answers
239 views

Influence of an inner gas giant over a solar system

I'm designing a solar system with three planets in its hot zone, two in its cold zone and three in its habitable zone. All of the planets are rocky worlds of various sizes, except for the middle world ...
13 votes
3 answers
5k views

What would the sky look like if there were 100 Sun-sized stars exactly half a light year away from Earth?

I'm thinking of a little something where a hundred Sun-sized stars would dot the sky (night or day; the Sun just blocks other stars at day after all). These stars are scattered across the sky, but ...
3 votes
5 answers
381 views

Earth with no sunlight

What phenomenon could stop or reduce the sunlight on Earth? I am thinking about a prolonged solar eclipse. Is it possible for it to last for years? If not, is there a way for the sun to stop shining ...
16 votes
3 answers
4k views

I come out of hyperdrive as far as possible from any galaxy. How isolated am I and what do I see?

I come out of hyperdrive as far as possible from any galaxy. How isolated am I and what do I see? My purpose is to carry out a top-secret experiment where space is as flat as possible. For this ...
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 ...
12 votes
2 answers
761 views

Could a planet's tidal forces break an asteroid passing very close to it?

I want a certain asteroid of my system to break into pieces as it approaches a planet, having one fragment impact the planet itself, another fragment slingshot and impact the planet's moon and the ...
2 votes
3 answers
1k views

Will life exist on Earth if it stops rotation? [duplicate]

Rotation is ubiquitous in the cosmos. Planets rotate, as do stars and galaxies. This comes about simply from conservation of angular momentum. What if Earth stops rotation ? How does it effect on ...
4 votes
2 answers
662 views

What is the minimum size of an habitable planet to have two moons?

For the sake of the question, let's define a moon as a natural satellite at least half the size of our Moon. It needs to be spherical like our Moon, not like Phobos and Deimos on Mars. The imaginary ...
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3 votes
2 answers
409 views

Difference between F type stars and our sun

I'm writing a science fiction series. I have an intelligent nation of reptilian people who live on an Earth-like planet orbiting an F-type star. This nation needs to bask in the sun. How will the ...
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19 votes
8 answers
3k views

Can a planet have asymmetrical weather seasons? Like 3 months for summer, fall and spring each and 6 months of winter?

I looked around for an answer and was unable to find it here. So can the planet have asymmetrical seasons? I want my imaginary planet to have winter doubled comparing to summer. And which astronomical ...
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8 votes
4 answers
2k views

Can Multiple Stars Naturally Merge Into One New Star?

Assume just for this question that in one same plane of space, there are the following stars within close proximity of each other: An O-type main-sequence star (18x wider, 15-90x more massive and 40k-...
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6 votes
8 answers
1k views

Navigating under a starless sky: how to determine the position?

My alternate Earth is placed, together with the whole solar system and nothing else, in the center of the Boötes void. At nearly 330 million light-years in diameter (approximately 0.27% of the ...
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0 votes
2 answers
141 views

Red Sun Plus Blue Sun Equals Magenta Sky?

Okay, my second cousin is working on a story that takes place on a planet named Odroia. It is an Earthlike planet with a supercontinent similar to Pangea, that has scattered rivers and lakes, with its ...
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2 votes
3 answers
142 views

How could we recover from being ejected from the solar system?

I just finished watching the newest kurzgesagt video on if the earth got kicked out of the solar system here: https://m.youtube.com/watch?v=gLZJlf5rHVs And I wanted to use that scenario in a story but ...

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