# Tag Info

## New answers tagged gravity

1

Spin it faster. Really fast. CoRot-7b for example is about 1.6 Earth radius (10k) and 8 Earth masses. It would be about 3G at the surface according to a gravity calculator I found. Rotation doesn't counter much gravity; the rotation the Earth counters less than a tenth of a percent of Earth's gravity at 24 hrs per rotation. However according to a ...

3

Depends, how high gravity do you mean? This study's summary https://arxiv.org/abs/1808.07417 for example suggests that 3-4 g might be doable for humans to train for. As for other life forms, they too should have no problem with that level of gravity. Of course, it would require adaptation, and prepare for human collonists to become fantasy dwarves rather ...

0

According to evolution: as big as they needs to be in order to survive and reproduce On earth the size of plants and animals vary greatly. Both mice and elephants thrive in their respective environment. I don't think there is much suggesting that mice would be better off if they were bigger, nor elephants if they were smaller. Same for plants, we have small ...

1

Typically the size of an organism doesn't increase or decrease because of a planet's gravity. The reason for the dinosaurs growing to their immense size and the large bugs that predated the dinosaurs is thought to be because of a more oxygen saturated atmosphere. Today's atmosphere is about 20% Oxygen, but when terrestrial life (mostly athropods) first ...

2

Lower gravity has many advantages. Primarily, it is easier to move things around, and you don't need (much) scaffolding, and structural integrity of whatever you are building is practically no issue. Yet, since all that has been mentioned, i would like to look at the flipside of the coin: provided you have humans working on the construction of your vessel, ...

9

I'd be doing all my large-scale construction and assembly in low Earth orbit. This has three major advantages. Firstly, although you're no longer protected by the Earth's atmosphere you are still protected by its magnetosphere, whereas the moon is mostly not. Secondly, lunar dust is an absolute nightmare. It gets everywhere, it has all sorts of unpleasant ...

4

From a purely structural point of view, building a spaceship in microgravity means that the structure will have to cope only with the intended acceleration assumed during the design. Building it on a body with its own gravity means that it will have to be factored into the calculation for the structure, potentially adding weight but in any case resulting in ...

1

Stretching the limits of physics, but well...there's magic involved: Gravitymagic could make lightmagic have mass (or behalve as it had). Then you could have a slower-than-lightspeed rod of light with mass and momentum, could be quite damaging.

1

Here's a question for you-- do the features have to be on the planet's surface? What about giving the planet rings and/or multiple moons that can observed at various times in the night and day sky? Those are naturally occurring in our own solar system, but they would make the skyline seem drastically different and alien. How about something like a magnetic ...

1

"The aliens did it" is always a good get out for fantastical structures, but if you want natural structures then gravity is not kind to huge arches and spires. They can exist to a certain degree for a while here (monument valley and similar) but truly massive monolithic structures probably wouldn’t work in an Earth like setting for the same reason that we ...

0

When distorting spacetime with gravity, you have to be aware than any manipulations you do that noticeably affect light will affect other stuff an awful lot more noticeably. To take gravitational lensing as an example, a GL deflects light passing by with an offset $b$ by an angle $\hat\alpha$: $${\hat {\alpha }}={\frac {4GM}{c^{2}b}}$$ Just taking orders-...

0

I've thought about how they might affect spacetime. Or the gravitational lens. Or the interaction of gravitons and light. But I haven't thought of many applications of such abilities. Right, but... Lihtcraft is the ability to manipulate light (both visible and invisible). The typical lihtcrafter spends his life constructing orbs and heat lamps. My ...

2

Other answers have focused on the force needed to move it, but it's a matter not only of force, but torque. Doubling the length of a weapon while keeping the width and thickness constant doubles both the mass and the lever arm, making the torque four times as large. And less gravity also means you weigh less, so your body is less of a counterweight, and you ...

0

He miraculously succeeded in every task, and the exhausted ministers eventually ordered him to just jump down a church tower. This phrasing is ambiguous as to whether it's "they ordered him to jump, such that his jump is from a church tower", or "there was a church tower such that they ordered him to jump from it", i.e. whether the choice was up to him ...

1

No, this will not work. The mass of the sword will stay the same, even if the weight changes, and so it will be just as hard to build up momentum as in the normal amount of gravity. Once you have finally used a lot of energy to swing the blade around, it will take the same amount of energy to stop it. Your enemy can just avoid that attack easily and off you ...

1

The physical process of piling up pillows may be a problem. The people will need to pile up the pillows in a pyramid like shape and the process of stacking may determine how stable it the stack is while people are passing pillows up the stack to the top, as well as how well the stack of pillows cushions the protagonist when he jumps. Did you ever hear of ...

0

Pushing the boundary of the definition of "pillow," I would go with very slippery pillows. There's little need for compressibility because I'm going to arrange them in a catenary or perhaps log curve (I'm too sleepy to apply the calculus to verify maximum vertical delta-vee applied throughout the slide). The fellow's total speed will slowly decrease ...

3

It's not that you can't lift it, it's that you can't maneuver the blade at all. Your average medieval arming sword has a mass of about 1kg. Say you now ramp that up to a 10kg blade. It has the same weight as before, so you can carry it around easily enough, but as soon as you try to swing it, you're going to find that 1) you can't get it up to speed ...

1

The problem in a setting with low gravity isn't the weight of the weapon so much as it is the weight of the user. Imagine if you weighed 1/10th your usual weight, and you're trying to swing a gigantic beast of a weapon. Would you be swinging the weapon around, or would the weapon be swinging you? With a normal weapon (i.e. normal Earth-sized weapons), the ...

0

If the pillow tower is near the height of the original fall, and people stand at the top of the tower to receive him in a “trust fall” like catch, you can make it happen. Human ladder with a pillow base.

7

No. The problem is that kinetic energy is based on mass, no weight. So you may be able to carry these giant swords along no problem, but accelerating them for a strike (or any swordfight maneuver) would still be very tiring and slow.

0

Sure, they make great shields If everything weighs 1/10th as much, yet human strength remains the same (and object density does as well) than that means arrows have a lot further reach alongside all ranged projectiles. And, since ranged projectiles are superior when you're dealing with unarmored infantry, that means the range game is deadlier at farther ...

1

there is not enough information given to calculate the number of pillows, like what are the pillows made of and what is their size. and the distance from the jump to where the pillows start, if the stack is 90 meters high then he will not accelerate much before his fall is slowed. given enough of the right pillows it is feasible.

3

If you want a really quick rule of thumb for things like this, which assumes no air resistance, and an ideal substance absorbing your fall (which produces the same deceleration at all levels of compression) then you can just use potential energy. The kinetic energy gained in the fall is mgH for mass m, acceleration = g, starting height = H. Suppose an ...

4

A 100-meter jump would break current world records for free-fall jumps. I do not believe this would be possible with pillows. Dar Robinson currently holds the world record for the highest free-fall jump in a commercial film at 220 ft (67 meters). That's 33 meters short of the church jump. That's with several safety precautions, practice, and training. ...

7

I don't believe he can walk away from this, period. Look at Itmauve's answer--stopping in 10 meters causes 5g of acceleration--done right, this is fine. But can you actually punch 10 meters into a pile of pillows? A quick look in the closet indicates that arranging pillows to make a human-size/shape landing (in a jump you would have extras because you don'...

38

Okay, from a height of 100 meters, the faller will reach a speed of 44m/s. Human terminal velocity, for a spread-eagle position like skydivers, is 53m/s, so drag is going to play a big role here, especially if he goes spread-eagle. Call it 32 m/s of landing speed. If our hero wants to stop in ten meters from this, assuming roughly constant acceleration, he ...

16

Without having the information to crunch numbers on this... I'm going to call it plausible, but only if the commoners have enough knowledge of physics. What you really need is to absorb energy slowly. For this to happen, your pillows will have to be able to "give" a lot, and quickly. Now, the good news is we are presumably talking about down pillows, as ...

2

Yes the force of gravity would still pull them towards the centre of the Earth. So they would fall “upward” and away from the mountain. The force of gravity would also reduce towards the centre of the Earth and at the centre of the Earth there would be a net zero gravitational force. But by that time they would have hit the burning core at very high velocity....

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