# Tag Info

19

As I mentioned in a comment, I am making the following assumptions about this planet: Twice the mass of Earth; $M = 2 M_e$ The same bulk density as Earth; $\rho = \rho_e$ The same atmospheric composition as Earth; The same surface temperature as Earth; $T = T_e$ An air column proportional to surface gravity; i.e. the total mass of air above any square meter ...

7

The assertion that an earth mass only a few meters in diameter having a surface gravity equal to that of earth is wrong. Surface gravity can be expressed by $$g = \frac{GM}{r^{2}}$$ so if you reduce $r$ from ~ six million metres to, say, six, the surface gravity is multiplied by the inverse square of that reduction. So the surface gravity of a six-metre ...

6

Honestly, we already live in the future. Autotranslation of spoken words and conversion of distances, especially in the context of a limited and precise vocabuary, seems entirely practical by the time someone has mastered interstellar travel. Alternatively: What would be the minimum information they would have to exchange to work as a functional sniper ...

6

The question specifies "proportional". If we assume twice the gravity and air density, then: The answer is no. Terminal velocity would be neither faster, nor slower. Note, the leaf would accelerate faster initially. But it would reach terminal velocity quickly. Terminal velocity is directly proportional to the sqrt of gravity and the sqrt of the inverse ...

6

Gravity is not the only thing to consider for atmospheric density; pressure (and by extension density but they are different properties) can also be increased by the amount of energy (read as heat) being stored in the atmosphere. Also, the relative strength of a magnetic field ( terrestrial or induced) can have an impact on how much of the atmosphere is ...

6

Internet is full of calculators if one searches for them. From atomic bomb to asteroid impacts, people can calculate anything. Spinning worlds included. Here is just the first of the list I found by googling. For a 2.5 km radius you get an angular velocity of 0.59 revolution per minute. For a 1.5 km radius you get 0.77 rotation per minute.

5

It's an interesting scenario. The major problem is that ring systems tend to be quite low-mass in comparison to their parent bodies. For example, measurements by Cassini indicate that in the case of Saturn, the ratio of ring mass to planet mass is $M_R/M_p\simeq2.7\times10^{-8}$ (Iess et al. 2019). Even in the notable case of 1SWASP J1407b, whose ring system ...

4

Yes an object would appear to get darker as its mass grows. A high mass object distorts spacetime and causes light to be stretched out or "red shifted" as it tries to escape. An object on he cusp of collapsing into a black hole would be so massive, that the light would be red shifted outside the range of human perception. This video explains it better ...

4

Anticipatory TL;DR: In order to have a large flying hexapod, you might want to consider adding: Flaps between limbs A habitat near some form of updraft - ocean winds, volcanic wind, or some manufactured thing. Honeycombed bones; an organ to create hydrogen An incredibly large diet; perhaps hibernation when this isn't possible Dense atmospheres Depending ...

4

The sniper's team's jobs will be obsolete long before we can travel between stars. The technology already exists to make self targeting rifles that are more accurate than nearly any human sniper, but in your more advanced civilization, this tech would easily be way beyond human limitations. This means that the guy holding the gun IS the spotter, and the ...

3

Tl;DR: probably no. But it might not even be required for what you want. The (simple, rigid-body approximation) for the Roche limit is defined as $d = R_M \sqrt[3]{2{\rho_M \over \rho_m}}$ where $R_M$ is the radius of the primary, and $\rho_M$ and $\rho_m$ are the densities of the primary and satellite respectively. Given constant densities, the Roche limit ...

3

So, there are a few things here. First of all, base 10 is NOT a safe assumption. The only reason humans use base 10 is because evolution gave us ten fingers, and even WE don't use base 10 for everything, we use a lot of base 12 and base 16 too. Second: all members of sniper/spotter teams are snipers. One member or the other may be the one actually ...

3

Short answer? Not really. Longer answer: The intensity of light isn’t altered by gravitational forces. If I shone light onto this hypothetical object the same number of photons would bounce back off it and climb up the gravity well. As the speed of light is the same for all photons (locally, at least!) there won’t be a proportion of photons lost, so the ...

3

Your primary premise is flawed. Earth and Venus have comparable gravities but Venus has 90 times the atmosphere. Venus atmosphere Other planets also differ widely. Saturn is huge but has close to Earth gravity, you can fit 1000 Earths into Jupiter but it has less than 3 times the gravity Planets gravity Neptune and Uranus are also close to Earth gravity, ...

2

Don't change gravity, change the materials it acts upon. Gravity is not actually the evil illuminatus depriving us of giant animals, machines and buildings, because gravity doesn't feature in the square-cube law at all; it's purely a geometric principle describing how doubling the linear size of an object squares its surface area and cubes its volume and ...

2

Distance and drop. Besides gravity, they presumably will have an unfamiliar atmosphere on this world. You might as well give them a rifle that neither is familiar with as well, loaded with weird osmium ammo. You can have the spotter measure distance to targets, pacing them off. Your sniper can watch thru the scope. When spotter returns it has pictures ...

2

All buildings, even the large ones, rely on gravity to rest them on the ground. Those that don't usually don't last long at all. You would be surprised that all buildings simply 'sit' on a foundation. By foundation, I mean a pile of concrete sitting on earth. The only elements that possibly you could refer to is anti-cyclone 'tie down' rods or straps. ...

2

Major nitpick: you've got a habitat that's 6000km across, presumably with a conventionally earth-density-and-pressure-and mix atmosphere in it. From the centre ofthe habitat, you're looking through 3000km of air. On earth at standard temperature and pressure, a square metre of surface has about 10.3 tonnes of air pressing down on it. A cuboid of air 3000km ...

1

We really need more information concerning the nature of your world, I fear that air resistance would destroy your world in short order. But I will attempt an answer. Given the situation I would assume that your “medieval” is not going to be an exact mirror image of classic Earth medieval since they will be flying between worlds, but it just means primitive ...

1

Your wording is slightly unclear but I'll answer on the basis that planet is 1.5x bigger (1.5x the radius) and 1.5x more massive than the Earth. Now the acceleration due to gravity F = GM/r^2 Compare your world with Earth: Fworld = G(1.5M)/(1.5r)^2 The surface gravity on your world with be 1/1.5 times that of Earth, i.e. only 67% of Earth gravity or about ...

1

If gravity was 1.5 times stronger, a flying creature would need 1.5 times the lift to fly. This could be achieved by flying faster or flying through denser air, but either flying faster or flying through denser air would increase drag. The net effect is 1.5 times gravity requires 1.5 times the power to fly. Given the limits seen in large flying creatures on ...

1

First i want to make something clear. Basically EVERYTHING produces gravitational lensing, as everything interacts gravitationally with everything. Even light. Only problem is, most masses are to small to have an measurable effect, so only bigger and more massiv objects are interesting. Now, there are objects massive and dense enough, that they visibly bend ...

1

To a first approximation, let's see what happens if we take the existing Earth and its atmosphere and dial up gravity to 2g. Pressure is just the weight of the column of air above your head. So if $g$ doubles, the pressure doubles. For a gas, $P \propto {1\over{V}}$ (Boyle's Law) $\rho \propto {1\over{V}}$ so near to the surface, the density doubles too. ...

1

This is a little outlandish (and, for the record, no I am not actually a pastafarian), but might give you ideas regardless... What is this "gravity" you speak of? Everyone knows there is no such thing. The reason stuff falls is because the FSM's noodly appendages push down on all things, because, y'know, just floating off into space would be super-annoying....

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