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# Tag Info

10

To generate a planetary magnetic field you just need a liquid metal where electrons can float freely. There are several options for this, these are a few examples which come to mind: Iron and Nickel This is the Earth setup, but I thought I'd mention it. Wikipedia explains pretty well how it is generated. Metallic Hydrogen This is the Jovian setup and ...

16

Yes. The fact that the Earth's core is made of materials that are ferromagnetic at standard temperature and pressure is completely coincidental--it has no bearing on the generation of the geomagnetic field. In the regions where the field is generated, iron and nickel are in fact not ferromagnetic. All that's necessary is that you have an electrically ...

-1

Grow the size of your planet First, about sources... This question doesn't ask for "hard" science, only a "base" in science; I'm citing a researcher who has done some work in this. YouTube isn't a source of proof, but a video can be a 3-D or animated model to explain an idea. Reportedly, the ocean floor age maps used in this video model are based on real ...

4

You are asking conflicting requirements. the surface of the planet becomes unrecognizable to an observer means that whatever feature is present on the surface is deeply altered or even destroyed. Thus a complex crater to form and remain stable cannot happen

2

Instead of trapping the humans on a valley floor surrounded by mountains how about having your medieval humans trapped on top of a tepuis. A tepuis is a mountain range with a flat plateau on the top and sheer cliffs all around the sides typically found in South America. The sheer cliffs that surround the plateau would make it incredibly perilous for a ...

1

Your scenario has a big problem: Trapped lakes will in time become saltwater lakes. Instead, you want your water to drain through the ground. You'll need some high, steep mountains to surround the area. They are volcanic but not explosive so they keep building up rather than blowing themselves to bits. The passes are upwards of 20,000' and thus ...

2

A large enough desert with no water sources would be impossible for medieval humans to cross. An extreme enough mountain range would also be close to impossible, especially if there are no passes. You could put the humans on a piece of land bounded on some sides by desert, and some by mountains. They would get their fresh water from these mountains, but the ...

5

It won't be easy, but I can think of a few possibilities, though they require rather unlikely geography. Large, circular valley: You have this large valley surrounded by tall mountains from which rivers run into a central system of lakes. There is a balance between evaporation and added water, or maybe there is an underground river that drains the lakes. ...

1

There are many types of terrain that would have presented a barrier to medieval people. Although mountains could be crossed via passes, mountains were seen as dangerous places and were generally avoided if at all possible. Very tall mountain ranges such as the Himalayas would have presented formidable obstacles especially if the passes were snow bound and ...

3

Mudflats. Their island/continent, which is nowhere more than a few feet above sea level, is completely surrounded by miles of sticky mudflat. The tides are so slight that any point they can reach from solid ground is never covered by more than inches of water, preventing use of even shallow draft boats. Any attempt to cross the flats on foot or with land ...

0

Probably not the direction you want to go, but if you make the land rich, fertile and with no big hazards (no typhoons, no quakes, no volcanos, no sudden floods, no draughts), humans would have less reasons to move somewhere else. Sort of an ancient Egypt like land, but on an island to prevent expansion wars, which require travels.

2

Below Sea Level A possible alternative is that the majority of your continent is actually below sea level, and you have something like a mountain range or various tall terrain features which actively prevent the sea from rising up and flooding everything (Think of the interior of Australia). Due to some extreme circumstances this natural barrier was ...

1

End of ice age A lot of "land" on Earth is actually ice and snow coming all the way from the seafloor. For example, during some ice ages you could go from nowadays Russia to nowadays Alaska by foot. The ice bridge was also probably more than a mile above nowadays sea level. Also check the answers for What would an Antarctica without ice look like compared ...

1

Define "rapid", but in the terms you're talking about no, there isn't. All the examples we have of submerged continents required millions of years to subside, and even then most of them still have portions above water. There isn't a realistic geological process that could cause such rapid subsidence over the sizes of land you'd be wanting that also didn't ...

4

Perhaps long ago a super advanced civilization decided that the planet didn't have enough land area and so built artificial continents. Instead of bringing stone from stony asteroids and piling it up on the sea floor to build continents that were giant rock piles, for some reason the civilization imported a lot of metal from metallic asteroids and built ...

4

Introduce a moon. Without a moon, the planet won't have any tides, so the sea level won't experience any short cycles. Add a moon, and you suddenly have variations in water height which on Earth can be as much as 15m. With a bigger, more massive moon you could easily induce even larger tides, enough to flood the majority of a low-lying continent. Note ...

4

It sounds like what you're describing is just a continent that's higher in the north than in the south. All you need there is a continental collision where your 'plateau' continent starts riding up over the one it's colliding with. That's exactly how the Himalayas happened, and unless I'm missing something, the entire Indian Subcontinent is a perfect example ...

2

Crack creatures. Super hard things crack. Your ocean would be traversed with immense cracks, and look like the surface of Europa. Nutrients, water and other things needed for life would be concentrated into these cracks and these 2-dimensional crack ecosystems would therefore be good places for life. Photosynthesizers would take up residence in the crack ...

0

Some scattered thoughts -- In a glass world - I imagine some form of silicon based life. The storms you describe remind me of sand-blasting and the kinds of rubbery materials used to block off the particles. This suggests the creature or being would have a silicone skin that constantly grows and sheds in tiny piece somewhat like our own skin. Glass though ...

3

Creatures would have to either live under deep canyons that have been eroded by time, Well, what is doing the erosion? Wind and sand? Probably not very good places to shelter! or be able to actually dig there way into the glass. You've already stated the glass is "super-hard". This rather limits the ability of any creature to dig into it. Even if they ...

2

Your story is set in California. It is a very cool thing to site your story in a fictional past of the real world. That lets you riff off of real and legendary things from our world and also frame things out in terms of real geography. A prime example: Robert Howard’s Hyborian Age for the Conan stories is set in Europe around 10,000 BC. A more recent and ...

8

Campania You main character lives in Campania, one of the most fertile and pleasant regions of Italy, probably somewhere near Capua. It being a region in Italy, mountains are never far away. (It is situated on the western side of the peninsula, south of the central region of Lazio.) The land is exceptionally fertile; agriculture has been the main business ...

2

a cold volcanic [...] moderately toxic soil to the extent that the people there have an inborn resistance to it and can in fact be quite healthy and strong, but many are noticeably diseased and/or deformed. This can be a volcanic region, with an active volcano and a significant release of radon from the ground. an ocean, ideally warm, that experiences ...

1

According to the USGS it would look like this: Source: https://water.usgs.gov/edu/gallery/global-water-volume.html The larger sphere represents all of Earth's water, while the smaller sphere represents Earth's fresh water. The larger sphere has a diameter of 1384 km, quite large but only 0.13% of the total volume of the Earth. Ice has a density 92% that ...

4

Volcanoes become extinct when their magmatic chamber is no longer supplied with new magma from the mantle. But like when you turn off the fire under a pan of boiling water its content stops boiling but stays hot for a while, so does the magmatic chamber. The heat from the molten lava will slowly diffuse outward, until, over geological time, the lava will ...

2

Yes, there are many “extinct”, or more precisely, dormant volcanos that still emit heat that drives hydrothermal activity. Perhaps the best known example is Yellowstone. It has not erupted in a while and it’s not going to erupt in a while. However, the pools in the Yellowstone area support unique ecosystems of microorganisms and larger animals. Hakone in ...

9

So, lets say there's about $1.8*10^{21}$kg of water on the surface of the earth (this excludes hydrates and stuff in the mantle, but the surface stuff seems like the bit most likely to be deposited by impacts after earth's formation). Given the density of ice, $920kg/m^3$, that much water would form a solid sphere about 776km in radius. That's Quite Big, by ...

4

If you want to have the total hydrosphere being delivered on a single impact, let's first check the mass The total mass of Earth's hydrosphere is about $1.4 \cdot 10^{18}$ tonnes That means $1.4 \cdot 10^{21}$ kg. As references, Mimas has a mass of $3 \cdot 10^{19}$ kg, while Enceladus has a mass of $1.0 \cdot 10^{20}$ kg. That's a major impact. As a ...

12

Estimates for the mass of the Chicxulub impactor that offed the dinosaurs range from 1015 and 4.6 $\times$ 1017 kilograms. The hydrosphere's mass is currently estimated to be around 1.4 $\times$ 1021 kilograms. That is like 10,000 Chicxulubs in terms of orders of magnitude, if we use the upper bound for Chic's mass. Might be more like 100,000 dino-killing ...

1

The planet has an eccentric orbit around a gigantic microwave emitter Many high-energy cosmic objects - the most notable being neutron stars and black holes - emit high levels of microwave radiation. Your planet orbits one of these (alternatively, a binary star where one of the pair is a neutron star or black hole) and has a highly eccentric (elliptical) ...

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