28 votes
Accepted

What is the largest fraction of Earth's sky that an astronomical object could take up (visually) before ripping Earth or itself apart?

The calculation turns out to be pretty straightforward and relies on two equations. Say the two objects have masses $M_p$ and $M_s$, with radii $R_p$ and $R_s$, with the $p$ denoting the more massive ...
HDE 226868's user avatar
  • 101k
20 votes

Life on a planet with never-ending rain

What would life be like on a planet where it rains constantly, assuming conditions similar to Earth? The Netherlands and the UK manage it pretty well, they just complain a lot about the weather. ...
L.Dutch's user avatar
  • 287k
17 votes

Life on a planet with never-ending rain

assuming conditions similar to Earth? I think you have to assume that it won't be globally that similar to Earth. The problem you have is that planets are big, and the climate is very variable across ...
Starfish Prime's user avatar
17 votes

How could Venus be partially terraformed?

Big parasol near L1. Put a big (roughly Venus-sized) solar sail slightly sunward of the Venus-Sun L1 Lagrange point. By varying the size or reflectivity of the solar sail, we can slightly increase or ...
g s's user avatar
  • 5,340
9 votes

Can a Venus-like planet be habitable if it was farther from the sun?

Habitable for humans? Probably not. For other things? Sure, why not. Lets assume you've handwaved away the inconveniently hot air, and unpleasant atmospheric mixture. You're still left with a surface ...
Starfish Prime's user avatar
9 votes

Can you have a planet as bright as Venus orbiting at 1.0 AU with no significant atmosphere?

TL;DR: you need a binary planet if you want to get that sort of view. So, the moon is big enough and bright enough to be seen by the naked eye, and large surface details can be identified. ...
Starfish Prime's user avatar
7 votes

How could Venus be partially terraformed?

Vacuum tank technology has really been a godsend for Venusians. While hardened robotic excavation and mining operations are proceeding smoothly on the surface and provide plenty of raw materials for ...
Serban Tanasa's user avatar
7 votes

Frozen World Atmosphere?

The frozen atmosphere would be present as a layer of ice, which would slowly, very slowly, sublimate away. It would take more than 4 billion of year to deprive the frozen planet from all of its ...
L.Dutch's user avatar
  • 287k
6 votes

Feasibility of a bio-engineered, floating tree lifeform in the Venusian atmosphere?

I worry that something the size of a tree may be very fragile. If it has a tiny leak it may start to fall. How about something smaller? How about an aerial version of a volvox colony. This would be a ...
Richard Kirk's user avatar
  • 8,753
6 votes

How could Venus be partially terraformed?

What technology levels are to be used to terraform it? Without that information, we can pick some farily simple ideas, that do not require super-tech: Using a solar umbrella to partially shield Venus ...
Going Durden's user avatar
  • 2,297
6 votes
Accepted

Time dilation on a heavily oblong planet

It is very, very hard to tell, but it hardly matters Mesklin is so oblate that Newton's shell theorem stops applying: even according to Hal Clement himself that "To be perfectly frank, I don't ...
controlgroup's user avatar
  • 3,326
5 votes

Can a planet with rings support life?

Life on Earth has evolved over something like 4 billion years. Saturn's rings probably will last for another 300 million years. As you get closer in to the sun, the three-way gravitational ...
Richard Kirk's user avatar
  • 8,753
5 votes

Life on a planet with never-ending rain

It washes out the ground over time, similar to australia which is so old it has seen alot of rain. https://en.wikipedia.org/wiki/Australian_Plate So very little nutrients and those usually captured in ...
Pica's user avatar
  • 3,996
5 votes

Feasibility of a bio-engineered, floating tree lifeform in the Venusian atmosphere?

Extracting water from the ambient sulfuric acid would be an incredible feat. Concentrated sulfuric acid will rip the water right out of carbohydrates, leaving a pile of carbon soaked with somewhat ...
Christopher James Huff's user avatar
4 votes

How could Venus be partially terraformed?

You need a solar umbrella. Most ideal point for that is the Sun-Venus L1. A 10000km big foil would be enough. Note, its mass, for example in the case of a 0.1mm width, is still years of the whole ...
Gray Sheep's user avatar
  • 3,646
4 votes

How to calculate the Draconic month on a fictional world

Here's the equation for the Draconic month length Tn where: e is the eccentricity (note that the equation only works when this is close, but not equal to zero) a is the semi-major axis u is the ...
Mathaddict's user avatar
  • 14.1k
3 votes

Frozen World Atmosphere?

As a gas? No, obviously. Oxygen and nitrogen freeze too, just like water, only at a much lower temperature (54.36 K = −218.79 °C = −361.82 °F for oxygen). For example, Earth's atmosphere would be ...
AlexP's user avatar
  • 89.3k
3 votes
Accepted

I have a world with two moons, and I was wondering how often they would both be full at the same time

If you have multiple moons and want to keep track of them, I'd suggest using a fantasy calendar. With one, you can get the exact places of the moon, as well as other helpful features. There is a ...
ShadowOfHassen's user avatar
3 votes

What are some things to keep in mind while designing a binary planet system with a sun-like star?

Rule of Cool Worldbuilding is an Art, an art of the fantastic. The main thing you need to keep in mind is quite simply: is this a true representation of my imagination? As an artist, your main goal ...
elemtilas's user avatar
  • 40k
3 votes

What is the largest fraction of Earth's sky that an astronomical object could take up (visually) before ripping Earth or itself apart?

At first thought, the absolute maximum apparent diamater of a companion world in the sky of a habitable world would have to be 180 degrees since if any portion of it appeared to extend more than 90 ...
M. A. Golding's user avatar
3 votes

Can you have a planet as bright as Venus orbiting at 1.0 AU with no significant atmosphere?

Considering that two planets following the same orbit is a very unstable configuration, I think your only safe bet is to have two planets orbiting around their center of mass around their central star....
L.Dutch's user avatar
  • 287k
2 votes

Can a planet with rings support life?

Rings usually form when a smaller body disintegrates while in orbit around a larger one. This can either happen because of an impact (it is possible that after the impact which led to the formation of ...
L.Dutch's user avatar
  • 287k
2 votes

How could Venus be partially terraformed?

You cannot fix carbon dioxide into carbonates until the surface cools. We would probably need seas and we are way above the triple point of water. We would want to seed the atmosphere with some self-...
Richard Kirk's user avatar
  • 8,753
2 votes

Can a Venus-like planet be habitable if it was farther from the sun?

I am generally not a fan of comments where the conclusion is: If you want it to be so in your world just make it that way. However in this case, as the question is asked it is probably the only real ...
Gillgamesh's user avatar
  • 6,027
2 votes

What are some plausible, long-lived geophysical planetary processes which would consistently maintain reddish skies in a human-breathable atmosphere?

The immediate answer that came to mind, which would require the least amount of theorizing about atmospheric chemical compositions their interactions with light, is an eyeball planet. This is a type ...
FlightDeck0112's user avatar
2 votes

Can you have a planet as bright as Venus orbiting at 1.0 AU with no significant atmosphere?

A massive injection of radioactive material About 50% of the Earth's internal heat comes from radioactive decay. If you were to increase how much radioactive material there was in the Earth, it could ...
Nosajimiki's user avatar
1 vote

I have a world with two moons, and I was wondering how often they would both be full at the same time

The duration of a sidereal year of the planet is given as "about" 1.4 Earth years, or about 1.4 × 365.256 ≈ 511.358 days. Then the duration of a full cycle of phases for Satellite One is 17 ...
AlexP's user avatar
  • 89.3k
1 vote

Frozen World Atmosphere?

I haven't seen the obvious question asked, so I'm going to roll with it here: just how cold are we talking? Mars receives a little less than 1/2 the energy from the sun per square km and has an ...
Corey's user avatar
  • 7,215
1 vote

How to calculate the Draconic month on a fictional world

The draconic month is equal to a sidereal month (= orbital period of the satellite) minus the precession of the nodes during that sidereal month. If you know the period of the nodal precession of the ...
AlexP's user avatar
  • 89.3k
1 vote

How could Venus be partially terraformed?

Catalytic conversions. Need high pressure. Check. Heat Check. Catalytic converters. Flow in and check. All that is needed is a heat pump, to concentrate the already present heat. Turn that canyon into ...
Pica's user avatar
  • 3,996

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