Hot answers tagged

79

Everyone else is speculating when there are proper reality check examples. Flight suits that allow for free movement of wings, legs and tail are a thing. Some also contain diapers, so that your bird won't poop on people's heads. These things are even fashionable. Someone even managed to bedazzle their pigeon. Your flying people could wear such harnesses.


64

It's more likely there could exist a plant which has a flying phase of its life-cycle. Does it really fly? It might be more appropriate to call it floating, since the energy required for what is more traditionally thought of as flying, would be too much for a plant. Blimp plants/animals have long been imagined in science fiction, called living gasbags. It'...


60

You could use the same back-up plan that the majority of flights in real life use: nothing. The vast majority of civilian flights in the real world have no parachutes. If a catastrophic disaster occurs in mid-air, then a loss of life will occur. The reason that this works out just fine in real life is that, especially in airline transport, catastrophic ...


57

Evolution Since the defining feature is not nesting on ground, the starting point should be the nesting behaviour. There should be a strong pressure to reduce time spent on the ground such as predators or competition for suitable locations with other species. This would favour a single very large egg that takes a long time to develop inside the female, but ...


57

Here is a scheme to sidestep some problems with steam engines in an alternate past. Problem: Fuel is heavy Solution: Do not carry fuel. https://images.fineartamerica.com/images/artworkimages/mediumlarge/1/mouchot-solar-concentrator-1878-science-source.jpg I introduce the good Mr Mouchot, a man ahead of his time. https://en.wikipedia.org/wiki/...


49

I would certainly expect the wheel to be invented. Sure, the society can fly, but can barrels of fine wine, flour, or iron ore? If the society grows large enough, it will eventually need to transport heavy goods and that practically requires the wheel. Whether food, metal, or wood, pretty much every soceity starts to transport goods heavier than one ...


49

Trees were not involved with the evolution of flight in birds. Birds did not evolve flight from gliders but likely from ground running predatory jumpers, birds and maniraptoran dinosaurs are about the most poorly designed climbers you could imagine there is zero support for tree climbing in early birds or their ancestors. So yes bird flight can and did ...


48

You may be missing why flight didn't happen until the early 1900s. Flight happened when engines became energy-dense enough. That's what they were waiting for. If it could've been done with steam, it would've. That said, with refinements such as the steam turbine (over the reciprocating pistons) and better metallurgy in the boilers aimed at making them ...


47

Let's revisit the premise that the sky-castle has a year's worth of water stored on it. As a corollary to this premise, we should assume that the stored water won't become stagnant or otherwise undrinkable. With minimal bathing and cleaning, just cooking and drinking and basic hygiene, the castle's smelly troopers still require about 5 gallons (16 L) of ...


46

This is looking long-term...after the initial surge of people taking to the air occurs has died down a bit. The airline industry would be untouched...no one takes a plane for a 15 mile trip. Aircraft move much faster and fly much further than your flight-capable humans. The same applies to cross-country trains. Bulk goods transport would be unchanged, as a ...


45

the air only gets denser, and denser The craft (or lifeboats stored on them) are very light. They are designed with lots of air spaces. When they start to fall, all openings to the outside are sealed and the oxygen is turned on. As the craft (or enclosed life-raft) falls, it eventually reaches a point where it floats in the dense atmosphere. At this point ...


43

From a safe distance, your sappers excavate a tunnel. The tunnel leads to the tether point of the castle's anchor chain. Bring the tether down into the tunnel from below. Winch it along the tunnel. You will winch the castle downwards. Defenders of the sinking castle will see their chain disappearing into a hole. They can rappel down and enter the hole ...


42

In a last ditch effort to prevent extinction (possibly one that worked, after all people are still here) a team of scientists released a swarm of nano-machines into the atmosphere. They form a slight (insert colour of choice) haze in the air at a height of X meters above (insert sea level/ground level/some other measure/do you want to allow skyscrapers or ...


39

The first flying insects appeared (as far as we know) in the Devonian, some 400 million years ago. Before that there were no flying animals. So not only is a world without flying animals possible, our own Earth was such a world for more than 90% of its history. The catch is that flight emerged as a life strategy almost as soon as there were animals living ...


38

For the sake of this answer, I will be assuming that by "castles" you mean late medieval/early Renaissance pre-gunpowder fortifications that were used for habitation as well as defense. I was also originally going to split this answer into two parts, depending on how difficult these creatures would be to kill or wound, but after some consideration, I ...


38

Ion flight. http://news.mit.edu/2018/first-ionic-wind-plane-no-moving-parts-1121 Unlike turbine-powered planes, the aircraft does not depend on fossil fuels to fly. And unlike propeller-driven drones, the new design is completely silent. “This is the first-ever sustained flight of a plane with no moving parts in the propulsion system,” says ...


36

Well, it all depends! :) There are tumbleweeds which grow, produce seeds, then die, break off and the whole plant moves by the wind, depositing its seeds in different ways, it's sort of like flying. Of course seeds fly all the time, dandelions and other similar flowers, Maples have their little helicopters. However, for plants to fly, first they need ...


36

Owls & co. already do this, thanks to the particular structure of their feather. Since I imagine your dragons don't have feather, they might have some structure leading to the same result. Another option can be that they simply start flying with a dive, like birds nesting on cliffs do. Just spread their wings and jump, gaining velocity thanks to gravity ...


35

The safest place is still aboard your airship. Unlike seagoing vessels, airships do not traverse a medium that is potentially deadly for humans. When a ship sinks, people need to still be able to float in water. Water is cold, wet and obstructs your respiratory passages if you breath it in. To stay safe in water you need to either swim or be on a floating ...


35

We call this "swimming" and you'd need an atmospheric density roughly that of water. The pressure needed to get a gas at that density has serious physiological effects, so just compressing the right gas mixture (one selected so as to not produce poisonous partial pressures of any of its components) wouldn't work. It is certainly possible to put enough ...


34

You would want to use a heating element. If you use a light (whether visible light from a LED or infrared from a quartz heating element), some of the energy is turned into light, rather than heat. If you have a transparent balloon, it escapes. If you have a black balloon, it gets turned into heat when it reaches the edge. But there's a catch. That heat ...


33

While in theory the atmospheric pressures and temperatures in the upper regions of Venus' atmosphere are more conducive to the operation of aircraft, you still have a problem; sulphur dioxide. This is one of the emissions that grounds planes during volcanic eruptions meaning that even if you can fly the plane there, the maintenance costs are likely to be ...


32

moving things around (mathematics argument) The wheel, or basically any spherical object, has the advantage of being the simplest shape which center of mass remains at the same height when rolling (something cubes don't have for example). That makes it the easiest shape to move around, thus the easiest way to move things around. This is mathematics, and ...


31

Sadly, no. Tl;dr: the minimum size of such a creature is on the scale of kilometers and thus pretty infeasible. Instead, try making the creature some kind of colonial organism and boosting your planet. First, let's consider the simple hypothetical: how much hydrogen would it take to simply lift a whale? Well, a blue whale weighs 200 tons- that's 200,000 kg. ...


30

I don't think a classic Pegasus/dragon animal will work (reasons see other answers). But how about a "lighter-than-air" approach? Your (gigantic) animal will split water into oxygen (can maybe be stored in special organs for fight-or-flight situations) and hydrogen. The hydrogen is then stored in large bladders, allowing the animal to float. It then can ...


30

Most planets in the solar system have their own magnetic fields(ref.), so you could use those to levitate. Just grab a huge chunk of superconductive material, and cool it below its critical temperature just as you're at the right altitude. Regarding your requirements: doesn't make much noise or noticeable influence: check. It might squeeze our ...


30

The same way a nautilus swims around in water: jet propulsion. Nautiluses move using a hyponome, which expands to pull in water from the sides of the nautilus, and contracts to expel a jet of water. The bio-blimps can majestically wheeze across the land using what is essentially an organic bellows, just like the nautilus. Whenever it wants to move, it ...


29

I've thought about this a bit in the past. It's possible, but only if the vessel moves vertically between regions of different wind speed. On a regular ship, lift forces can be generated on the sails based on wind moving faster than the sail. The water provides drag on the ship to keep it going slower than the wind. Essentially, the boat can 'push' against ...


28

Discounting the problematic flying fish, flight has evolved 4 separate times that we know of. Insects, 400 million years ago Pterosaurs, 230 million years ago Birds, 150 million years ago Bats, 50 million years ago. Given that we are considering "an earth-like world" with similar gravity and atmospheric composition, there is one one common denominator to ...


28

Gliding doesn't burn much energy An albatross can fly non stop for days simply by gliding. For something as large as a dragon, powered flight would use massive amounts of energy, which means gliding is vitally important to avoid becoming exhausted far too quickly. The dragon would still be gliding in combat. The dragon might have two to five minutes of ...


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