Questions tagged [astronomy]
For questions related to planets, moons, stars and other celestial objects, and their motion on the sky.
5
votes
2answers
475 views
Could a brown dwarf in our outer solar system remain undetected today?
We've all heard the on-again, off-again theories of another massive object in the vast reaches of the outer solar system. Some potential evidence to support the possibility are its affects on smaller ...
7
votes
1answer
84 views
Visibility of a Red Dwarf Companion Star
An interstellar traveller stands upon the surface of an alien planet beneath the light of an unfamiliar sun. The planet upon which he stands orbits one star of a binary system in which one is a G-...
14
votes
4answers
5k views
Would mining huge amounts of resources on the Moon change its orbit?
Imagine that humanity builds mining facilities on the moon. We know that the moon has Helium-3 which could be used as fuel for fusion reactors. Also, there are a lot of other resources which could be ...
7
votes
4answers
97 views
Light spectrum from a red dwarf star on a planet with an ozone and cloudy atmosphere
What light spectrum would hit the surface of a planet orbiting a red dwarf star?
The planet has a humid, greenhouse, & cloudy atmosphere, and a strong ozone, 80%+ surface water.
Planet is ...
6
votes
2answers
184 views
Black hole collides with Sun: How rapidly is energy released?
Basic idea: Primordial black hole (2.5% of Sun's mass) directly approaches Sun at fairly rapid pace (300 km/s).
Consequently, six days after passing Earth's orbit, it will collide with the Sun; ...
9
votes
1answer
184 views
To make a blue moon, what element does it need?
We know that Mars has a reddish color, because its ground consists of iron-based compounds. The moon is grey-whiteish because it consists mostly of silicon-based compounds.
What element should the ...
3
votes
2answers
103 views
Is there a plausible causal mechanism to explain why the Sun would be heating up faster/ sooner than we thought?
I am writing a novel about what it will be like on earth 500 or so years before the death of our Sun. The Sun is heating up gradually and one day that will negatively affect life on Earth. I know that ...
-3
votes
1answer
280 views
In a world with 12 moons but NO sun, how to define a day? [closed]
I made the map of my fantasy world before thinking about the physics, as you can see bellow the art!
I'm interested to understand how to decide which moon is in the sky at a given moment, if it's ...
13
votes
18answers
4k views
How can a moon have an ever-changing face?
Imagine an inhabitated planet like ours with a moon of the same projected size in the sky. The moon has visible structures of colors or darker and lighter areas.
Every evening when the moon gets ...
4
votes
2answers
196 views
How much heat would a 1km asteroid release into earth's atmosphere?
I am writing a theory for a game that is in an apocalypse. An asteroid is heading for earth and will crash into the earth regardless in this theory. It is 1km in size but due to the YORP effect it has ...
1
vote
1answer
204 views
Is it possible to divert a 1km Asteroid from Earth?
I am writing a scenario for a game that I am a fan of. It involves an asteroid heading for impact with the Earth in 2027. This asteroid's initial diameter is about 1km, but it is slowly disintegrating ...
25
votes
13answers
6k views
How can a planet have a deadly eclipse-like “spotlight”?
A solar eclipse occurs when the moon passes between the Earth and the sun. The result is a giant shadow that sweeps across the Earth's surface.
This world has the opposite phenomenon. Instead of a ...
7
votes
10answers
273 views
Plausible reasons for multiple hot seasons in one solar year
Setup:
A planet generally with an earthlike climate, although slightly wetter and warmer as a general rule, with a little more oxygen in the atmosphere, but habitable by unmodified humans. Still has ...
12
votes
4answers
2k views
How close could another solar system be without adversely affecting our own?
I would like to know how close two planetary systems could be without having an adverse effect on each other. My goal is to drastically improve the chances of having habitable planets near enough that ...
5
votes
4answers
140 views
Small eclipse on earth
Could one make a smaller eclipse kept stationary on the surface of the earth in order that one may be able to see the stars 24/7 from one site?
How could this be achieved?
Geostationary satellite ...
60
votes
24answers
12k views
How could a planet have a sky without stars at night?
Is it possible for a planet in our part of the galaxy to have a night without stars?
I'm looking for some kind of natural phenomena that would hide the stars, but allow the sun to rise and fall as ...
6
votes
1answer
345 views
Does my plot point centered around eclipses make sense?
My main antagonist is an infant Great One that's been imprisoned below the Moon's surface and I want its influence and physical form to have a weakness to direct sunlight which, I think, gives me a ...
23
votes
6answers
2k views
Scientific explanation for a exceptionally bright night sky
On an alternative Earth live the people of Tcelonia.
One of their founding myths goes that, in the dawn of times, when they were under the menace of being attacked by an enemy population, for an ...
34
votes
11answers
5k views
What's an astronomical event which happened about 10,000 years ago, which humans could have noticed?
Bob is older than he looks.
Specifically, even though Bob looks like he's in his twenties or thirties (it's hard to tell), he was actually born in Europe about ten thousand years ago, long before the ...
6
votes
2answers
335 views
How far out can a pre-telescope human society (naked eye observations only) detect planets?
There are many questions on WBSE that cover most aspects of building a planetary system. (some examples below):
Creating a realistic world(s) map - planetary systems
How many planets should I have ...
7
votes
2answers
140 views
Let's float an island on an astrophysical jet
An astrophysical jet is a stream of particles emitted by matter falling into an supermassive star/black hole, travelling at up to 80% the speed of light.
A troll with a portal gun (which places ...
5
votes
2answers
103 views
Naturally maintaining an atmosphere being stripped by a brown dwarf‘s magnetosphere
In this scenario we have a brown dwarf with a powerful magnetic dynamo from metallic hydrogen. The magnetic field is modeled after Jupiter’s but just three orders of magnitude more powerful.
...
5
votes
1answer
164 views
Explaining a Low-Mass Brown Dwarf
Considering the well-established relationships between stellar mass, surface temp, and luminosity, how unusual would it be to find a star (or brown dwarf) that possesses about half the mass of an ...
9
votes
2answers
347 views
A supermassive black hole is coming our way. When's the latest that we would notice?
I'm trying to build a story around a supermassive black hole, which is ejected from a merger of two galaxies, that is hurtling our own way. What is the smallest realistic distance at which the black ...
-1
votes
1answer
123 views
Estimates for undetectable planets in extra-solar systems [closed]
Based on answers and comments on some previous questions (especially this one), and as very clearly illustrated by the scatter-plot here, there are some very definite limitations on our ability to ...
8
votes
6answers
1k views
Can a 15km, rapidly-spining asteroid go undiscovered until the asteroid belt is being actively explored?
What I want to know is if an asteroid about 15 KM in diameter and roughly double that in length, spinning at a significant speed, could go undiscovered until a crew of an asteroid mining ship happened ...
3
votes
3answers
202 views
Could a comet cool down global tempatures? [duplicate]
In warlords I wanted Terrans to have a fad of big (synthetic) fur jackets, but I didn't want too have everyone running around in winter clothing for no good reason so the solution my mind instantly ...
5
votes
4answers
307 views
What requires more destructive energy? Destroying a planet or splitting a planet in half
I just wanna ask which option requires more destructive energy?
Option 1 : destroying a planet like earth to rubble (tiny pieces of rocks)
Or
Option 2: splitting a planet like earth in halves (2 ...
4
votes
2answers
93 views
What are some plausible formation explanations of a non-hot “Fluffy” Gas Giant planet?
So, in my research and preparation for the question I asked immediately before this one, I was introduced to the concept of "fluffy" gas giants, gas giants with significantly lower density than would ...
3
votes
1answer
348 views
Feasible star + planet + moon combo? Did I miss anything that makes this system wildly unstable or otherwise impossible?
Here's what I've come up with:
The star:
A main sequence star, roughly a sol analogue
Younger than Sol (say 3-3.5 billion years old)
roughly the same starting mass as Sol, but has had less time to ...
6
votes
1answer
324 views
Could [life on] Earth Survive a Gamma Ray Burst?
[EDIT: this question is about life on Earth surviving, not the physical destruction of the planet]
Could the Earth survive a gamma ray burst if that burst occurred in our galaxy and the Earth is in ...
9
votes
8answers
2k views
What is our planetary defense capability against an Earth life destroying object?
This is World Building through a preventative measure.
The Earth has been destroyed a few times in the past and it will happen again in the future, it is just a matter of time. For the first time in ...
3
votes
2answers
63 views
Opaque Solar Shield in Geosynchronous Orbit: Plausibility + Challenges of Maintaining Orbit
Suppose humans of the late 21st century or beyond began constructing a solar shield as a solution to climate change. Suppose for some reason (open to suggestions) they choose to build the shield in ...
4
votes
2answers
133 views
Editable map of local stars
I'm looking for a map of stars within a few hundred LY of the Sun. I'd like to be able to add text tags to stars, so I can name them within my SF universe. Then I'd like to be able to rotate the image ...
5
votes
6answers
252 views
What sort of setup of a binary star system would allow only one sun to be “up” at a time?
I have a sci-fi/fantasy world with two suns. Only one sun can be present in the sky at a time. A full day-night cycle would be:
Night time
Sun 1 rises
Sun 1 sets
Sun 2 rises
Sun 2 sets
Night time
Is ...
7
votes
3answers
180 views
Are there any plausible 'alternative' methods of planetary formation?
The selected answer on this question provides an extremely good, and detailed, description of what is generally accepted to be the main (only?) way a terrestrial planet can form, i.e. through ...
4
votes
2answers
480 views
What would happen if a little less than half of the moon crashed into the Atlantic ocean? [duplicate]
Let's say an asteroid hit the moon and broke it in half. One half remains where the moon usually is relative to Earth, and the other half is flung at Earth near the equator, in the Atlantic ocean. ...
43
votes
11answers
9k views
How long will it take to discover they live on a moon and not on a planet?
In my alternate reality, Earth is not a planet. It is a moon and orbits a gas giant (however it has all of Earth's characteristics, it is also full of humans and life as we know it). This is the only ...
10
votes
1answer
128 views
Increased Luminosity in Stars
I'm trying to construct a solar system, and I'm toying with the idea that the planet capable of sustaining life was initially outside of the habitable zone, but the star's advanced age has caused the ...
1
vote
1answer
146 views
Big moon, small planet - can an earth sized moon orbit a moon sized planet?
I know that objects with lower mass tends to orbit objects with higher mass, is it possible to have a Moon sized planet who's mass is so heavy that an Earth sized planet orbit it as it's Moon in a ...
9
votes
3answers
3k views
How can I locate myself in a random point of space?
Some Context
I'm creating a universe where humanity has reached the stars. They've colonized a few star systems and, obviously, FTL drives are a common thing. They basically jump you to another ...
0
votes
4answers
119 views
How to determine the shape of the world given that there are no astronomical cycles?
Inspired by this question, how might one determine the shape of the world given a cosmology with no cycles? The moon, sun, stars, and planets are all fixed. The Earth does not rotate. You can't ...
6
votes
2answers
108 views
How to distinguish the different phases of the day when the sun rises and sets multiple times?
Obviously there would be a lot of small (not to mention a couple large) changes humans would need to get used to on a planet that rotates much faster than Earth. The biggest one I’m concerned about ...
5
votes
1answer
116 views
Is it possible an ice line from pole to pole in a tidally locked Earth-like moon?
I am aware that there are a lot of answers explaining the fundamentals of a tidally locked "Earth-like" moon around a giant gas planet. For example this one:
Habitable moon of a gas giant: working out ...
10
votes
8answers
802 views
Which part of the universe would make celestial navigation most difficult for a planet?
Premise
I envisage a world of would-be navigators with roughly Bronze Age technology, sailing on ships to explore their planet. In contrast to our history of navigation where we "cracked the code" ...
-2
votes
3answers
72 views
How can I modern time traveler determine solstice and equinox?
A XX century researcher time traveled back into the prehistory. He is not in danger of death or anything, but he has only energy to attempt one jump.
He must jump back during the sunrise either in a ...
10
votes
3answers
383 views
How can the Hertzsprung–Russell diagram be used in star building?
As you can probably guess from the title, I have some questions about the Hertzsprung–Russell diagram, especially how to use it to make plausible stars.
Some questions:
Can stars exist in the black ...
25
votes
7answers
7k views
How would skeptics know that a single-engine plane could not destroy a falling meteor?
So I'm writing a story and decided to use Hida Furukawa as the location. It has a high school with a field of 650 ft that theoretically could be used for a small aircraft to be use to take off. In the ...
1
vote
3answers
115 views
Weather among the average tropical coastal regions? (I can't be more specific than this since i lack a map, I apologize) [closed]
I have a super-earth world. The surface of the world is shallower due to extra gravity, so shorter mountain ranges and less ocean depths. The world orbits a binary star system at a distance of the ...
4
votes
4answers
206 views
Changing Earth's axis suddenly or gradually?
First post, if it isn't completely obvious. I've discovered this site by trying to "google" that question. Here's what I'm investigating:
Long ago, pre-deluvian civilizations built ancient megalithic ...
