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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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Weather and climate of tidally locked, inhabited moon with oceans

This follows another question that brought me some curiousity about the general state of an earth-like moon tidally locked to a gas giant planet. There's been questions about a world tidally locked ...
Nicolás Marzano's user avatar
30 votes
4 answers
5k views

A planet illuminated by a black hole?

Is it possible for a planet to be heated and illuminated by a black hole due to Hawking radiation at the same intensity as by a star? What mass and size should a black hole have to produce the same ...
Anixx's user avatar
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6 votes
4 answers
2k views

How To Make an Earth with 27 Suns Work, Attempt Two: Orbital Stability

This is the continuation of a thread of related posts on a hypothetical alternate universe/Light Plane. Other posts from this thread are here: How To Make an Earth with 27 Suns Work Radiation Levels ...
FoxElemental's user avatar
  • 3,246
4 votes
2 answers
630 views

Is an earthlike planet with ammonia oceans even plausible?

The idea of a planet where ammonia replaces water as the dominant liquid in the environment is quite popular in science fiction. I tried to develop a scenario where these kind of oceans are plausible ...
TheDyingOfLight's user avatar
50 votes
20 answers
13k views

Killing a star safely

A messenger from the stars just arrived in peace but has brought horrible news. A vast swarm of planet devouring phototropic insects are approaching from deep space and our only hope is to obscure or ...
Henry Taylor's user avatar
  • 69.2k
14 votes
2 answers
551 views

Rogue Planet Illuminated by Galactic Centre

The black hole question reminded me of an idea I wanted to implement at some point in a space campaign, but didn't go forward with because I was unsure whether it's merely statistically very ...
vicky_molokh's user avatar
  • 1,811
12 votes
6 answers
3k views

Do seasons occur on a tidally-locked planet?

I have done some research and so much contradict one another or I simply fail to understand. Do seasons occur on a tidally locked planet that isn't tilted on its axis?
Mister Onion's user avatar
10 votes
3 answers
573 views

What would be the structural impact of an oscillating orbit on a planet?

Notice : If you wish to know how to make an oscillating orbit with real-world physics, you can looky-look at this question which is following mine. My question focuses on the consequences of such ...
Tortliena - inactive's user avatar
9 votes
3 answers
381 views

How Can I Explain a Giant Equatorial Gash?

I have a moon in my story that has a thin, deep gash or canyon that lies on its equator and spans the entire moon. My original idea involved the sudden orbital decay of a ring system, caused by a ...
overlord's user avatar
  • 6,312
6 votes
1 answer
646 views

I've determined how many planets my solar system could plausibly have. How do I figure out what kind of planets they are?

The 12 planets in my solar system orbit the G-type star of Nemo. It's about nine-tenths of the size of the sun, and has a stellar luminosity of 0.67 L☉, a diameter of 1.28 million kilometres, a ...
SealBoi's user avatar
  • 14.9k
3 votes
3 answers
242 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,...
Zayoul's user avatar
  • 33
43 votes
9 answers
7k views

How much damage would a cupful of neutron star matter do to the Earth?

Suppose we used SCP-261, the vending machine that produces anything, and ask for a cup of neutron star. The machine instantaneously produces this. Suppose also that the vending machine is located at ...
Quadratic Wizard's user avatar
21 votes
9 answers
4k views

Earth is accelerated out of the solar system - do we keep the Moon?

I've been reading about stellar engines. The Wikipedia article on them says this about the acceleration they could provide to a star: Such thrust and acceleration would be very slight, but such a ...
The Square-Cube Law's user avatar
14 votes
1 answer
474 views

Radiation Levels and Effects on Planet with 27 Suns

Other posts from this thread will be posted here: How to make an Earth with 27 suns work (Closed as a duplicate of the follow up, Attempt Two) How To Make an Earth with 27 Suns Work, Attempt Two: ...
FoxElemental's user avatar
  • 3,246
11 votes
1 answer
517 views

What sets of stellar models are freely available for reference when worldbuilding?

Often, when I'm building a world, I want to start out by determining some of its key properties. Maybe I'm trying to calculate a habitable zone, or figure out how long a year would be on a particular ...
HDE 226868's user avatar
  • 102k
10 votes
6 answers
2k views

How could a breathable ultra-high pressure atmosphere form?

Some background: I'm developing a world that could, theoretically, be inhabitable by humans (with a high enough recruitment success to at least keep a stable population), randomly determining ...
Coel's user avatar
  • 837
9 votes
3 answers
608 views

How could formamide lakes form on an exoplanet?

I've been recently looking into alternative biochemistries for life and the environments were these could be found. I already asked a question about how ammonia oceans might form a while back. Today I'...
TheDyingOfLight's user avatar
9 votes
4 answers
654 views

How far should second star be in my binary system?

For a certain reason, I needed two habitable similar earth-like planets very close to each other. After various information gathering, I gave up on double planet and gas giant moons, because tidal ...
Failus Maximus's user avatar
9 votes
1 answer
415 views

Orange Suns and Blue Jupiters

I am developing a fictional planetary system in which a large gas giant planet (slightly less than the mass of Saturn), has migrated into the habitable zone during the formational years of the system, ...
Arkenstein XII's user avatar
7 votes
1 answer
156 views

How do Hill spheres work for binary planets?

A small moon is able to maintain a stable orbit around a planet at just under half the radius of the planet's Hill sphere. Most of Jupiter's moons are in this configuration, possibly made more stable ...
Charles Rogers's user avatar
7 votes
1 answer
360 views

What would be the effects on a planet orbiting a shedding red giant?

In a sci-fi RPG I eventually intend to run for a couple of friends, I had the idea of them visiting ancient ruins on a planet orbiting a shedding red giant. Now, ignoring the problem of intelligent ...
Nobbe's user avatar
  • 314
7 votes
3 answers
332 views

Seeking good physical candidates for total collapse of the universe we live in

Bringing this question over from Physics SE where it was closed: I'm looking for an 'as close to our understanding of current physics' doomsday scenario that results from something about the physics ...
William Walker III's user avatar
6 votes
1 answer
792 views

How could you build an artificial planet-sized magnetic field?

I'm conceiving of a world where humans can readily terraform worlds that were once considered "dead" due to the planet's magnetic field being long gone. In such a situation, what could humans do to ...
Richard Boone's user avatar
5 votes
4 answers
405 views

What would the local effects/affects be of a ring spinning near luminal velocity?

To better solicit more inline with what I'm trying to imagine, I'm editing my question, the original question is left below and removing the hard science tag, as that just seemed to cause issues, ...
Gillgamesh's user avatar
  • 6,213
5 votes
5 answers
669 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's user avatar
5 votes
3 answers
364 views

Enlightening Dark Matter?

As an ironic twist, I wanted a story in which dark matter is actually caused by light. Somehow, the physics of light cause it to create the appearance of the existence of dark matter. But I'm not a ...
DWKraus's user avatar
  • 64k
5 votes
7 answers
629 views

"Landing" a small asteroid on Earth

I've been poking around similar posts, but none seem to contain the information I'm looking for. I'll try to keep it brief. In the year 20XX, some powerful organizations are trying to "land" an ...
DMQ's user avatar
  • 1,068
5 votes
3 answers
1k views

Would a water-bearing, Earth-sized moon orbiting a gas giant have tides?

I ran across this article today about how moons might have moons. In Daniel Keys Moran's universe, an Earth-sized planet named November orbits a gas giant named Prometheus. November is inhabited, ...
J.D. Ray's user avatar
  • 1,668
4 votes
2 answers
485 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
  • 41
4 votes
1 answer
364 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 (...
KEY_ABRADE's user avatar
  • 13.1k
2 votes
0 answers
59 views

Could a rogue planet support life? [duplicate]

I was wondering whether a free floating planet could potentially host life. If so, how? I was thinking of a geothermically active planet, where the only source of heat comes within the planet itself. ...
Liam00's user avatar
  • 267
1 vote
1 answer
138 views

Would a gigantic meteor impact in the Strait of Gibraltar create a peak-ring crater, or at least a complex one?

Background: A peak-ring crater is a sub-type of complex crater (an impact crater in which the impact wave rebounded from the rim of the crater and pushed up a mountain in the middle) where, instead ...
KEY_ABRADE's user avatar
  • 13.1k
1 vote
1 answer
163 views

Is there a formula for scaling explosive detonation velocity? (Supernova level) [closed]

For context, I’m planning a novel with as much ridiculous magic as ridiculous science so, yes I know, it’s impossible but bear with me. There is a supermassive black hole that weighs 1 trillion solar ...
ashy's user avatar
  • 11
1 vote
2 answers
715 views

Building a planet with a primordial black hole core

I have been trying to figure out a way of explaining how an advanced society some time in the past built an artificial planet with a black hole at its core and the effects that would have on the ...
Althaen's user avatar
  • 377
0 votes
1 answer
162 views

Would a meteor blowing up the Strait of Gibraltar 2 million years ago kill all of humanity's ancestor species?

Let's say that, 2 million years prior to the present day, a meteor impacts roughly in the middle of the Strait of Gibraltar. It is large enough and strikes at sufficient velocity to create an impact ...
KEY_ABRADE's user avatar
  • 13.1k