The Quick Questions About World Building Thread

A slower shift of the axis of rotation can shift Japan into tropical climate, as can greenhouse gases from a carbon-rich impacting comet.

Climate models have been used to model the effects that changing the axial tilt and apoapsis/periapsis have, since they are two key Milankovich cycles and mediators of the onset and end of ice ages.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

Yeah, the problem is that changing the Earth's rotational axis or axial tilt is a huge freaking deal that would have catastrophic global effects and might even wipe out all life on the planet.

edited 9th Feb '18 11:46:36 AM by Fighteer

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

Would any of these consequences manifest within less than a century after the shift happens, even if we assume a convenient Hand Wave like, in the specific case of Neon Genesis Evangelion, "Adam was surprisingly benevolent enough to exert the last bits of its Reality Warper powers to mitigate/contain most if not all of the mass extinction-causing catastrophic effects of its Superpower Meltdown, so that only about half the human population was wiped out within the next six months of chaos and the geological upheaval and tsunamis ultimately didn't leave any drastic changes on the world's geography"?

edited 9th Feb '18 6:08:49 PM by MarqFJA

Fiat iustitia, et pereat mundus.

A shift of the axis manifests itself as a matter of less than a year. Greenhouse may take longer.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

What about the potentially-all-life-wiping catastrophic global effects that Fighteer alluded to?

edited 10th Feb '18 7:57:20 PM by MarqFJA

Fiat iustitia, et pereat mundus.

Neither change results in catastrophic consequences by itself, the issue is the amount of force needed to shift the Earth's axes.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

Indeed. The problem is that there's no way in the realm of physics to accomplish such a change rapidly without exerting an unimaginable amount of force, and that force would have catastrophic consequences. The last time the Earth got hit hard enough to change its tilt, it was struck by an object the size of Mars and the impact blasted out enough material to make the Moon. Nothing would survive it, and the Earth would take millions of years to cool enough for life to possibly evolve again.

Now, you could apply that energy "gradually" over a long period, like a year, which would significantly reduce the force needed, probably enough to prevent it from being an instantaneous extinction event. Or you could use magic, in which case any scientific analysis becomes moot. But if you did it over a long period, then you'd still get some huge tectonic effects as well as shifts in ocean levels, climate, and weather, and you'd need that supercomputer to model everything.

edited 12th Feb '18 9:24:42 AM by Fighteer

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

Actually, upon thinking about this I am not certain that a comet impact would do the job. Assuming an entirely carbon dioxide based comet, in order to double atmospheric carbon dioxide concentrations (the total mass of atmospheric carbon dioxide is about 3*10^12 tons and the density of a comet is about 0.6 g/cm3) the comet would need a diameter of over 20 kilometres, about twice that of the Chicxulub impactor and the ones that created the Vredefort and Sudbury impacts.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

Try cutting the comet into smaller bits. Like the comet fragmented and some of the pieces hit the planet with every orbit, gradually changing the orbit over the course of centuries.

Also, look into gravity boosting. A near miss can apply some inertia from one object to another via gravity. When they talk about a slingshot maneuver around Jupiter they're talking about hanging behind Jupiter for a bit so that it's gravity will drag you around.

This has the benefit of not needing to collide things but the disadvantage of being slow and tricky to set up. You'd need an object of comparable or greater mass than the Earth to affect Earth's orbit in any significant way per pass. You've also got to worry about tidal effects of such an large object and the affect of the Earth on the other object.

...Unless you plan for the Earth to have a freak near miss with a phantasmal gas giant. Talk about astrological horror stories.

edited 12th Feb '18 8:54:57 AM by Belisaurius

A comet could change the planet's atmospheric composition enough to cause greenhouse warming, but no conceivable comet could have enough mass and velocity to change the Earth's rotation. You'd need an impactor with the mass of a planet to accomplish that. Or maybe a close pass from a rogue interstellar black hole* or something equally exotic would work.

* Don't try this. If a black hole powerful enough to shift the Earth's rotation passed that close to us, it'd also disrupt the planet's orbit around the Sun. That this would be bad is kind of underselling the point. The science is also out on whether such things as sub-stellar-mass black holes roaming randomly through space even exist. So-called "primordial black holes" would probably be much, much smaller and wouldn't measurably affect the Earth's rotation even on a direct hit.

edited 12th Feb '18 8:56:35 AM by Fighteer

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

Actually, my idea was to have a comet impact increase the atmospheric greenhouse gas concentration. I suspect that having an impact shift the axes would require an even larger body than for a greenhouse driven climate change, and splitting it up does not help - impact events cumulate as well.

Now I am wondering if a smaller impact on the East Antarctic Ice Sheet may do the job; between meltwater, dust rainout and resulting albedo effect, shockwaves and the like the ice sheet would be completely destroyed at a sufficiently strong impact event. However it is not clear that the albedo effect from the disappearance would warm the Earth overmuch, to say nothing of the effects of the disappearance on global atmospheric circulation.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

"We've successfully altered Earth's orbit. Also, everybody is dead from Hawking radiation."

Amusing, but a stellar-mass black hole wouldn't emit enough Hawking radiation to be harmful at a distance that isn't already close enough to its event horizon to be inescapable without super-science drives, and a black hole small enough to emit significant radiation wouldn't have enough mass to alter Earth's orbit or spin.

The point is that gravity strong enough to change Earth's rotational axis would have an even stronger effect on its orbit, making the exercise kind of moot.

Sure, but more frequent, smaller impacts have less of an immediate effect from the impact itself, so you get fewer of the fireball/earthquake/tsunami events.

The Earth gains a few kilotons of mass every year from meteors and interplanetary dust ^note (The Earth isn't getting heavier, though; we lose more mass to the solar wind than we gain from dust, for a net negative.); most of that material is harmlessly buffered by the atmosphere. But if we get hit by forty kilotons all at once, we're in serious trouble.

edited 12th Feb '18 9:15:27 AM by Fighteer

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

Hey, so I'm currently working on a world set a few centuries After the End, with the "end" being several nations waging warfare with WMDs roughly equivalent to nukes in short-term destructive power. However, the nations in question had Schizo Tech, and said WMDs were superpowerful inceniary bombs that, though they aren't really radioactive, can still reduce a city to little more than ash and slag and still be burning a week later (sometimes longer, as illustrated in Real Life by areas such as Centralia, Pennsylvania, a surprising amount of which still burn to this day). Damage was made more severe by the fact that this Constructed World's nations relied even more on fossil fuels than we do. The result is a scorched wasteland, blasted of most forms of life by both the initial damage and the global warming that followed, extremely dried up in most areas, and covered mostly in dust. Are such incendiary weapons feasible, or will it have to be explained away a Magitek?

edited 14th Feb '18 3:04:49 PM by SomethingRandom113

Umm... so, I was here, I guess. If I wasn't, someone hacked my account. So, yeah.

You'd probably have to handwave it. A conventional bomb with the same power as a nuke would be too huge to actually use. I'm also not sure that type of destruction would lead to a desert enviroment, but that can be handwaved too.

They should have sent a poet.

If you want to deploy nukes, deploy nukes. It's the only way we know of to generate enough destructive power in a device that's physically possible to deliver at range. Nukes would create massive firestorms, so you're good there. The main problem that you don't get with conventional explosives is fallout.

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

Magitek it is, then. No, I'm not ready to deal with the consequences of radiation in this world. I want a scorched-earth incendiary fallout. Less Chernobyl, more Centralia / Thirsty Desert / Mount St. Helens.

The fact that this world has magic makes it much more feasible.

edited 14th Feb '18 4:30:30 PM by SomethingRandom113

Umm... so, I was here, I guess. If I wasn't, someone hacked my account. So, yeah.

Centralia and St. Helens are both still fairly wooded, they're hardly the Sahara.

I'd go with straight up magic though, you can pretty much do anything with that.

They should have sent a poet.

I know, I meant incorporating elements of all of those, like a mash-up of all of the bad parts.

Umm... so, I was here, I guess. If I wasn't, someone hacked my account. So, yeah.

If you could somehow make a pure fusion bomb — one that skips the primary fission reaction that, in modern devices, creates the necessary pressure for hydrogen fusion (the secondary reaction) — you'd get almost no fallout at all. There would still be a lot of high-energy gamma and x-ray radiation, but none of the heavy radioactive decay products that poison the landscape for hundreds or thousands of years afterward.

edited 14th Feb '18 9:05:05 PM by Fighteer

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

Fallout from nuclear weapons isn't even too huge a concern anyway. Within a few decades it'll be clean enough to live in again.

Oh really when?

What behavioral/ evolutionary changes can be expected by plants, animals, and humans in a world where a day lasts a year such that their equivalent of the four seasons are dawn, day, dusk, and night?

edited 24th Feb '18 6:33:20 PM by Bend-It-Like-Zuko

You should probably make your own thread for that, since that doesn't sound like it'll be a quick question at all. And when you do, clarify how long this planet's day and year are, because my first thought was a 24-hour day with 6-hour seasons, which probably wouldn't support life in the first place, if it's not outright physically implausible in our universe.

"Jack, you have debauched my sloth."

Such a planet would have to be orbiting ridiculously close to its parent star. Mercury, the closest planet to our sun, has an orbital period of 88 days and a semi-major orbital axis of 57,909,050 km. I used an orbital period calculator that I found on Google to estimate that our hypothetical planet with a 24-hour year would have to have an orbital radius of about 3,000,000 km, 20 times closer to the Sun than Mercury.

At that distance, the planet and anything on it would be fricasseed. Also, it'd be tidally locked, so there would not be any "days". The Sun would take up such a large portion of the sky that the idea of seasons would be kind of moot; there might be some difference in sunlight intensity at different points in its orbit if it had enough axial tilt, but it'd be trivial. In addition to direct light, tidal heating (the twisting of the planet's insides due to the different gravitational pull from one side to the other) would make the place even hotter, possibly even permanently molten. Fortunately, 3,000,000 km is still well outside the Roche limit for an Earth-Sun system — that's the radius at which tidal gravity literally tears a satellite apart.

You might be able to have a habitable world at such a close radius if the star in question were a red dwarf: a star that barely has enough mass to achieve hydrogen fusion and so has a correspondingly low brightness. Of course, conditions on such a planet would be drastically different than anything you might find on Earth. For one thing, the light from the star would be incredibly dim and far into the infrared part of the spectrum, so any life there would probably see much differently than humans. There's also the problem that red dwarf stars tend to be very volatile, occasionally brightening or dimming in ways that would make any life clinging to a nearby planet very uncomfortable. See this Wikipedia article for more.

Interestingly, we know of such a star that is very close to us: Proxima Centauri is a low-mass red dwarf with a habitable zone starting at a radius of 0.032 AU; a planet in this zone would have an orbital period of a mere 6 days. That's still more than in your proposal but at least it's getting close.

White dwarf stars (like ours will become in six billion years or so) are another hypothetical possibility for the survival of life towards the end of the stelliferous era of our universe. It takes billions of years for them to cool down to inert lumps of carbon, and for some of that time, a planet extraordinarily close to one might get enough light and heat to remain habitable. Of course, getting it there would be quite the trick of astroengineering, as nothing that close to a star would survive its red giant expansion phase, never mind having been habitable beforehand. Assuming you can't just teleport planets around the cosmos, you'd need to take an existing, habitable world, gradually increase its orbit to keep it in the habitable range as its parent star aged and died, then move it back inwards after weathering the storm of the star's death throes... somehow. Or you might find a lifeless lump of rock already in orbit around a white dwarf and terraform it.

edited 26th Feb '18 8:29:47 AM by Fighteer

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

It's actually a day worth 365 earth days, not a year worth 24 hours. Sorry for the confusion. So we are dealing with 3 months of daylight and three months of darkness with twilight seasons in between.

I am not sure about year length or what kind of star for it to orbit, but I was inspired by the earth 's polar regions and desire to spread the midnight Sun / polar night effect to more temperate and tropical climates. I have a large ocean which should alleviate some of the extreme temperature gradient and the strong winds which would be produced where the opposites meet are taken to consideration in my story.

I will create a new thread to answer my biological and cultural questions, but your orbital simulator is interesting and I would enjoy further feedback.