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107 votes

Sword in the rock - make it last the ages

Make the Legend last through the ages So, Merlin telemagicks to 5000 years ago, presents the sword-in-cement LEGEND to some fancy king. Then he rigs up some scenario where the sword is found. People ...
Mirror318's user avatar
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95 votes
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Sword in the rock - make it last the ages

Merlin knows about metallurgy, and will place in the immediate surroundings of the rock (or even IN the rock) a sacrificial anode made of magnesium, aluminium, zinc or another suitable metal. A ...
L.Dutch's user avatar
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72 votes

Ensuring an endless war, and an endless stalemate

What your son wants, and in fact you describe /and when their opponent is vulnerable for the final blow, will say: "See you next time" and go home./ is counting coup Any blow struck against the ...
Willk's user avatar
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71 votes

Sword in the rock - make it last the ages

Can there be hereditary Servants of the Sword? These folks would live nearby, working the earth etc but they take responsibility for periodically going out to visit the Sword and putting a fresh coat ...
Willk's user avatar
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60 votes
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A hang glider, sudden unexpected lift to 25,000 feet altitude, what could do this?

Getting caught in a thunderstorm is the most likely cause. This can happen even to experts if they are incautious enough to take risks with the weather. Here's an example with a paraglider. (I'll see ...
chasly - supports Monica's user avatar
59 votes
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Can blood form snowflakes?

It's hard to believe but I have some RL experience with freezing blood (cow blood!). It freezes rather well, but at lower temperatures (about -5C). When it freezes blood "essence" (this red-...
ksbes's user avatar
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58 votes
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What would be the effect of a giant magical fireball burning in the ocean?

Let's say your magical sphere has radius $r$ of 10km (so just poking up into the outer atmosphere) and is at a temperature $T$ of 1,250K (so glowing a nice warm yellow). The total radiative heat flux ...
Stephen's user avatar
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54 votes
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How to avoid boats on a mainly oceanic world?

Just make it so wood does not last on seawater Your planet has a variant of the Shipworm, similar to the Earth variety except that it contains its own cellulose-dissolving enzyme rather than relying ...
PcMan's user avatar
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53 votes
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If rain magically started falling over the Sahara, what would happen?

Something like this has actually happened once already 100 years wouldn't be enough to turn the Sahara into a savanah, but it would be a good start. From this source we read the following (emphasis ...
JBH's user avatar
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51 votes

Is it possible for people to live in the eye of a permanent hypercane?

The eye is a region of mostly calm weather at the center of strong tropical cyclones. The eye of a storm is a roughly circular area. It is surrounded by the eyewall, a ring of towering thunderstorms ...
L.Dutch's user avatar
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50 votes
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What would be the necessary conditions to rain bubbles?

Let's assume for a moment that there are bacteria living in clouds. These have to feed on something, but nutrition in clouds is scarce. The chances of collecting molecules with nutritional value ...
Elmy's user avatar
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49 votes
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How can a planet have a deadly eclipse-like "spotlight"?

A wobbling pulsar will do the trick. Pulsars emit a lot of energy in narrow beams that come from their poles. The slowest ones flash every few seconds; make its tilt wobble so that it is not pointing ...
The Square-Cube Law's user avatar
49 votes

Under what conditions would a space battle involving a relatively large number of vessels be barely visible on the surface?

This battle is invisible, even at night I've got bad news, and I apologize sincerely... but you did tag your question "Science-Based." Consider the distances involved: The earth's diameter ...
JBH's user avatar
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45 votes

What would make a place always misty?

Plant respiration Rainforests are famous for making their own rain. Plants transpire something like 98% of the water they take up. When you have a lot of plants, and it is already pretty humid, the ...
kingledion's user avatar
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42 votes

Sword in the rock - make it last the ages

Let it rust. Seriously. A thick chunk of steel is already going to last ages without any special treatment. It will corrode on the outside for sure, but this adds to the authenticity of just how old ...
CactusCake's user avatar
42 votes
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Ensuring an endless war, and an endless stalemate

Different approach, after the Comment on my other answer: Maybe that's just how immortal (or very, very long-lived people) always fight - it's how it's always been. Dwarves have fought each other ...
Syndic's user avatar
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41 votes

Is it possible for a planet to have the same seasons in both hemispheres?

Yes it is possible, if the planet has little axial tilt but an eccentric orbit. Then summer will be when it is closest to its sun, and winter will be when it is furthest away, which will be the same ...
Mike Scott's user avatar
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38 votes
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Scientific explanation for a exceptionally bright night sky

Supernova. A type II-P supernova maintains a fairly constant brightness for several months, and one at an appropriate distance (something like 500 light years) will be as bright as the full Moon for ...
Mike Scott's user avatar
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38 votes

How can glass marbles naturally occur in a desert?

Your desert glass pebbles are volcanic glass. In the US they are called Apache Tears. source These are unpolished, as found in the desert. When polished they are a very beautiful deep black and ...
Willk's user avatar
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37 votes

How can I make raindrops bigger?

Decrease Gravity Explanation: The water droplets we experience on earth are mostly so small because of gravity: when a water droplet becomes too big, gravity rips it apart before it can get bigger (...
Soan's user avatar
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36 votes

Tropical beaches and snow topped ski slopes

Mount Kilimanjaro is located close the equator (03°04′33″S 37°21′12″E) but its 5895 m high top is covered with permanent snow . Even better, the Mauna Loa, located on Hawaii Island, can give you a ...
L.Dutch's user avatar
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36 votes
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How can a desert have high humidity?

You're in luck! We already have this action on Earth, in the Atacama Desert. Fog rolls in from the ocean, but the mist is so fine it doesn't fall as rain, hence preserving its desert-hood. Only a ...
akaioi's user avatar
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36 votes

What manner of weapons and armor would be suitable for freezing conditions in the middle ages?

Winter warfare (at given temperatures, which I would not call "Arctic") maybe uncommon, but absolutely realistic. For example, in the XIII century, Batu Khan's conquest of Rus' (a predecessor of ...
Alexander's user avatar
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36 votes

Keeping an "hot eyeball planet" wet

What keeps my planet's water from irreversibly concentrating over time on the frigid wastes while the rest of the planet dries up? When ice piles up, it will exercise pressure. The closer to the ...
L.Dutch's user avatar
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36 votes
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What would happen to the world if all lightning stopped?

For one thing, natural bushlands would get overgrown. Anyone who listens to world news knows that the south west of the US; California and Arizona especially, are prone to bushfires. So is most of ...
Tim B   II's user avatar
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36 votes
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How could a planet logically have green clouds but still be habitable?

Algae. You could simply state that on this planet there is some kind of micro- algae that lives in the tiny droplets of water that make up the fog and the clouds and that happens to be green.
elPolloLoco's user avatar
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35 votes

If rain magically started falling over the Sahara, what would happen?

That is a lot of rain Runoff will carve rivers as excess water goes to the ocean. Take a look at the basins to see what will happen. It appears there will be five basic river systems. There will be ...
kingledion's user avatar
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34 votes
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How can glass marbles naturally occur in a desert?

There are 3 types of natural glass: obsidian (volcanic glass), impactite (meteor glass), and fulgurite (lightning glass). Naturally round impactite is virtually unheard of. Impactite tends to have ...
Nosajimiki's user avatar
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34 votes
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How cold does it have to be to freeze a waterfall

How cold does it have to be to freeze the waterfall? Obviously, below freezing. The colder it is, the faster the water will freeze. Depending on the size of the river and the brightness of daytime ...
Starfish Prime's user avatar
34 votes
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Can I set fire to the rain?

Alkali metal dust The Alkali metals lithium, sodium, potassium, rubidium, cesium, and francium, all react violently with water when in their elemental pure form. If a dust storm consisting of small ...
Mathaddict's user avatar
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