Questions tagged [astrophysics]

For questions regarding the application of the laws of physics to orbital mechanics, stellar evolution, and other astronomical processes and celestial bodies.

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F type and K type Star Binary

I'm designing a worldbuilding project and the first major hurdle I'm encountering is the star(s) I want to have. The primary star is an F9V - F8V star with a mass of 1.13 - 1.15 Solar Masses, a radius ...
Dono's user avatar
  • 181
3 votes
1 answer
79 views

Calculating the Amount of Time for the Precession of the Equinoxes [duplicate]

OK, so in the process of building a world for my D&D campaign, I have gotten very into the science of world building. Where I have gotten hung up is I want to have a realistic length of time for ...
ZeldaChloëRose's user avatar
2 votes
1 answer
107 views

At what approximate distance and what size should binary planets be for a day to be no more than 30-32 hours long?

For the story I'm trying to find a more or less plausible description of the planet. Initially I was considering planet size like Mars or mid-size between Earth and Mars. Аnd this planet is in tidal ...
Tanya's user avatar
  • 23
7 votes
7 answers
5k views

What would happen if I fire a gun in an environment with hyper-gravity?

So I've seen a lot of research done into how guns react in low gravity environments as well as on space stations. However, for my story I was wondering how the trajectory, force and speed of the ...
Tycho's user avatar
  • 113
2 votes
1 answer
716 views

Radioactive planet wrecks civilisations every 5 millennia- How stable will it be?

Backstory Okay, so for now, let's pretend the creatures on this planet are just the same as those on Earth. Humans, cattle, pets etc, are just the same, cause I haven't yet thought up the biological ...
Furious Arcturus's user avatar
0 votes
2 answers
349 views

Implications of Venus and Mars having the same mass as Earth

Could anyone advise if there have been any simulations on the long term stability of our solar system if Venus and Mars both had the same mass as Earth ? If not, is this something that can be answered ...
Adrian's user avatar
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2 votes
1 answer
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Effect of molecular clouds on space travel and civilization

To What Extent are Molecular Clouds Geographic Barriers in Space? In a sci-fi universe I've been working on for quite a while, I have different civilizations that are initially unaware of each other's ...
EldritchEntity's user avatar
4 votes
2 answers
197 views

Solar Flare/CME Range Limits

The Setting: A binary solar system comprised of a KV-class Orange Dwarf, and an M-Class Red Dwarf which orbits roughly 600AU away. The Orange Dwarf has 4 planets orbiting around it, including one ...
Atlas the Worldbuilder's user avatar
2 votes
2 answers
160 views

If Earth were located at 1.1 AU from the Sun, would this affect the two zenithal passage days in the Tropics?

I am designing calendrics for an Earth-like planet located 1.1 AU from a Sun-like star. On Earth, on April 30th and August 13th, the Sun appears to pass directly overhead between the Tropics of Cancer ...
JM Yaden's user avatar
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2 votes
2 answers
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Could a captured planet end up in the habitable zone of a new star system?

Is it possible for a planet to be ejected from one star system and end up in the habitable zone of another? Or do captured planets always end up in wide, eccentric orbits? I guess in the vast expanse ...
Elhammo's user avatar
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Could a planetary object spin at (or near )the speed of light? [closed]

And if so, what would it look like to an observer on the planet and an observer in orbit around the planet?
marmel's user avatar
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What would happen to an Earth-like planet if it had a more magnetically permeable inner core?

I was contemplating the impact of doping an Earth-like planet's core with a substance that alters its magnetic permeability. Specifically, I considered a scenario where the planet has an improved ...
riotopsys's user avatar
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1 answer
163 views

Looking for a Specific Planet

I know my title isn't the most specific, but the planet I am looking for is. I have been looking through many exoplanets and I can't seem to find what I am looking for, the closest I have found is ...
Amoeba's user avatar
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4 votes
3 answers
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Could a slow rotating planet combined with high density atmosphere create high winds?

I am trying to design an alien ecosystem around a K type star. My idea was to have purple plants and high wind atmosphere so originally I wanted to make it tidally locked. However after watching some ...
Radu Dan Coroian's user avatar
1 vote
1 answer
224 views

How large should my supermassive planet's core be to prevent it from becoming a star?

My planet is a gas giant, it is called Klarloth (Inspired by a character from "Star Mouse" by Fredric Brown). Klarloth is a strange planet. For one thing, the planet is large in size, more ...
Furious Arcturus's user avatar
9 votes
8 answers
3k views

Stopping Milkdromeda, for Aesthetic Reasons

Basically, there is a human civilization controlling the milky-way and an alien civilization controlling Andromeda. They are communicating and have decided, for some reason, that, though the ...
skout's user avatar
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1 vote
2 answers
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Calculating distance of the frost- and ice line

To begin, my star is a K type star with 0.65 solar masses. I've inserted my star's mass in two different templates to calculate the frost line, yielding different results (2 AU and 2.68 AU). ...
Explunky's user avatar
  • 388
2 votes
1 answer
132 views

Would a planet with a retrograde spin function as if it were spinning faster or slower?

I am thinking in terms of the Coriolis Effect, atmospheric circulation and specifically Hadley Cell latitudinal width here, but the base question still stands. For ease of reference, if we take a ...
Rexotec's user avatar
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0 answers
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How many giant planets could form in a hierarchical triple star system?

The system in question has a very close binary pair of 2 G-type stars, a G9V and a G7V, orbiting at about 0.2 AU, with a K2V star in a far orbit about 300 AU out around the both of them. There is a ...
Rexotec's user avatar
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4 votes
1 answer
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Exotic life in a brown dwarf

From what I have seen in the discussions here about possible life on brown dwarfs, it’s concluded that no complex chemical life (even metallic or CNT based ones) can survive the radiation and gravity ...
Fredrik Hansing's user avatar
2 votes
1 answer
65 views

What stellar temperature, orbital distance, and eccentricity is needed to create an Earthlike orbital planet with a last glacial maximum climate?

I am creating an Earthlike planet with a year length of 515 Earth days and 9 Earth hours. I am aware that Kepler's third law of planetary motion states that warmer stars are needed for longer orbital ...
Galactic's user avatar
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3 votes
2 answers
126 views

How fast would this astronomical macromorph be?

I’m taking inspiration from Robert A. Freitas Jr.’s theory about alien metabolisms based on gravity rather than electromagnetism. He imagines astronomically sized beings that derive energy by ...
Fredrik Hansing's user avatar
2 votes
3 answers
312 views

KBC Void Stupendously Massive "Vacuum Hydrogen" generators- How to convert the Anti-Hydrogen into Hydrogen?

So, let me get this straight right here. According to Wikipedia: "The KBC Void (or Local Hole) is an immense, comparatively empty region of space,...... The underdensity is proposed to be ...
Furious Arcturus's user avatar
12 votes
12 answers
4k views

Alternate universe where life is more common; is it feasible?

Let's imagine a story where the "aliens" leave a lot of super-advanced technology somewhere in the solar system. Scientists spend years excavating this technology and while it seems too ...
Mishima's user avatar
  • 979
5 votes
3 answers
3k views

What are the repercussions of two asteroids in the asteroid belt colliding?

As the title states, what would happen if two asteroids in the asteroid belt were to collide? Specifically, two the size of 45 Eugina impacting with each other. In my story, I am thinking about having ...
yukimoda's user avatar
  • 542
8 votes
5 answers
3k views

Practicality of building a space station in the tail of a comet

In my novel, I want to feature a large (>5km) centrifuge space station that was built on/into a comet, and is in the comet’s tail whenever it passes close to the sun. It is home to many criminal ...
Whey_Isolate's user avatar
  • 1,347
3 votes
1 answer
228 views

How stable would partial planetary rings be on Lagrange points?

Context There's a comparison to what I'm talking about on a larger scale: Jupiter's got its Trojans and Greeks, and Earth does have them too. Those are more or less loose and sparse groups of ...
Yulian's user avatar
  • 442
6 votes
1 answer
345 views

What dictates whether an orbit gets disrupted or stabilised due to an orbital resonance?

Context: I've got an asteroid belt analogue situated between a Gas giant and a Super-earth. I knew about resonances, so I started calculating them and placing some of them in the belt, especially ones ...
Yulian's user avatar
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2 votes
1 answer
155 views

What is the difference in speed between my two moons?

The planet in my current project is orbited by two moons, which like Mars' are relatively small and irregularly shaped. The largest moon orbits closer to the planet and the smaller one orbits farther ...
INPU's user avatar
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1 vote
0 answers
81 views

Jupiter's moon Europa - is it possible to colonize Europa? [closed]

So basically, I have to write a thesis paper because I'm in the last year of high school. It is an independent research project and the culminating work of my studies in school, so it represents my ...
Gabriel's user avatar
  • 11
3 votes
4 answers
545 views

Any way of having a breathable atmosphere with zero gravity in free space?(and universal directionality?)

Inspiration This is heavily inspired by sunless skies in that sunless skies' world allows for the use of steam engines as space ship- equivalent (using steam jets as thrusters, while still able to ...
Harry Mu's user avatar
  • 363
1 vote
1 answer
80 views

How would these characteristics of a habitable planet in a triple star system affect the needed aspects of having two moons?

If a habitable planet is in a hierarchical triple star system (not unlike alpha Centauri) and has two moons but has a large torrid zone, what characteristics would my moons need to have in terms of ...
Amy May San Nicolas's user avatar
6 votes
1 answer
252 views

433 Eros hits the Moon. How much rock hits the Earth?

A la this image I made. The "how" (nuclear pulse drive "adjusting" Eros's orbit at its aphelion) and "why" (uber-sized Rods from God) isn't particularly relevant — all ...
KEY_ABRADE's user avatar
  • 12.8k
2 votes
2 answers
120 views

Effects on gravity on close binary planets

Let's say there's 2 planets orbit eachother as close as possible so they're oval shaped but not close enough to reach the roche's limit and be pulled apart. How would gravity be affected on the ...
Explunky's user avatar
  • 388
20 votes
7 answers
4k views

Can I warm up outer space?

My universe was created without stars, of any kind (which includes the sun!), and has continued that way for about 2000 years. To clarify, all life (intelligent life) was created by the deities around ...
celerysticks's user avatar
8 votes
3 answers
2k views

If someone blew up mars, how screwed is earth?

Mars has a gravitational binding energy of ~5x10^30 jouleS. If a bomb went off on mars that released that much energy, how much danger would the earth be in. Additionally, would debris striking earth ...
Adam Kabbeke's user avatar
  • 1,973
6 votes
5 answers
589 views

How can we prevent the Earth being scorched and swallowed as the Sun grows and eventually enters its red giant phase?

The Sun is slowly growing more and more luminous. As a result of these processes, multicellular life forms may be extinct in about 800 million years, and eukaryotes in 1.3 billion years, leaving only ...
Victor Stafusa - BozoNaCadeia's user avatar
8 votes
4 answers
1k views

Would two people standing on opposite sides of a flat world be able to see the same constellations?

Quick drawing illustrating what I mean: Two people (humanoids, between 1 and 2 metres tall) are standing on the ends (less than 1km from the edge) of opposite faces of a flat world (approximately ...
Whitehot's user avatar
  • 2,541
2 votes
1 answer
211 views

Tides on a tidally locked planet

Picture the classic Earth-like tidally locked planet, with a frozen dark side, a boiling stormy light side, and a thin strip of habitable land along the terminator. The planet is similar in size and ...
MoholyNagy's user avatar
  • 1,107
2 votes
2 answers
164 views

How would a planet with three suns, orbiting only one work?

Okay, I am planning to make a planet that has three suns, and orbits one of them. Each of the suns has its own orbital path, so it's possible for the planet to have one sun, two suns, or three suns in ...
Tyson Dennis's user avatar
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 ...
KaffeeByte's user avatar
  • 1,692
4 votes
1 answer
132 views

What is mathematical formula for finding the mean surface temperature on a planet in our solar system?

This question is to assume the common solar luminosity of approx $4 \times 10^{26}$ Watts. The mean flux of Earth at, for example, 1.1 AU would be about 1176 watts--but how can I calculate mean ...
JM Yaden's user avatar
  • 305
6 votes
4 answers
987 views

What is a reasonable day length for a planet with 4 times earth radius?

The fictional planet has a mass of 18 times Earth's and four times earth's equatorial radiusreference. This gives it a gravitational acceleration of 11.02m/s^2 (1.29G) and an escape velocity of 23....
Mindwin Remember Monica's user avatar
3 votes
6 answers
290 views

Obliterating the Earth, *without* throwing rocks? [closed]

In this case, I don't mean "make the Earth uninhabitable", I mean "make the Earth a debris field". This has been asked before, of course, but the answers always seem be be some ...
JustasidequestNPC's user avatar
6 votes
2 answers
137 views

How large can the main disk of spiral galaxies get? [closed]

I'm asking how large (by which specifically I mean diameter in light-years, though a rough estimate of the number of stars would be appreciated) can the main body of the spiral galaxy get. I'm ...
Ushumgallu's user avatar
3 votes
1 answer
159 views

Dealing with extreme heat and pressure in an underground colony on Venus

A colony has been constructed by robots for human habitation deep under the surface of Venus. They are totally sealed off from the surface, and the galaxy beyond, and live like a ship in a bottle What ...
EversonThomas's user avatar
0 votes
0 answers
111 views

How long would Earth be habitable after being knocked out of orbit? [duplicate]

Let’s say a rogue planet or something came close enough to Earth to knock it out of its orbit. Whatever event causes this, can this happen without disrupting human life in the short term and how long ...
Luke B.'s user avatar
  • 101
4 votes
5 answers
1k views

How would a spaceship not affected by gravity navigate between planets?

Presume there exists a metal called X-matter that has all the properties of steel, except it is repulsed by normal-matter instead of attracted. (For instance, a block of it would accelerate 9.81 m/s/s ...
Sean Harris's user avatar
8 votes
5 answers
529 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, ...
JuimyTheHyena's user avatar
4 votes
2 answers
418 views

What are the effects of Increasing the gravity on Mars?

I'm interested in the Physics around increasing the gravity of Mars to make it habitable. I was unsure how to work out what gravity would be needed to retain an atmosphere thick enough to hold liquid ...
Lily's user avatar
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