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Kepler's Laws give us the velocity of everything in the debris field and comet cloud-- At any radius, $i$, the velocity of the circular orbits (and a good rough definition of a "belt", although th...
Here's a first-order approximation based on a fundamental limit: diffraction and angular resolution. How far someone can see of course depends on the size of the object they're looking at, because...
Rather than copying the list of resources to here, I suggest that interested parties browse the answer to this previous question (A list of worldbuilding-resources?) where an humongous long list of...
The collapse of bubbles on various scales has actually been an area of research for quite some time. Analyses are typically numerical, and rely on something known as the Rayleigh-Plesset equation, ...
Both this site and Wikipedia assert that L4 and L5 are stable for a mass up to about 25 times the mass of the secondary. Since plain old Jupiter is about 318 Earth-masses. Since a) 318 is more than...
It's pure handwavium... but it's not completely absurd. As noted in Christopher's answer, powerguns work via a hand-wavium reaction that generates plasma from a specially formed matrix of "stuff" ...
For a star of that mass, you are looking at a G0V to F9V main sequence star. It's luminosity, depending on age, is probably around 1.2 sol, from which you can calculate the bounds of the habitable ...
This star would not fuse gold. Fusion reactions producing elements beyond zinc-60 are not energetically favorable; they are endothermic, and so consume energy. Several elements heavier than iron a...
As mentioned; we already know there are rogue planets and possibly even black holes out there. Is the fleet in question cover an area the size of Jupiter? Why wouldn't the better explanation be t...
As you've stated, the paper you cited gives the rate of atmospheric mass loss as approximately $\dot{M}=10^9\text{-}10^{11}\text{ g/s}=10^{6}\text{-}10^8\text{ kg/s}$ of hydrogen. We can convert th...
A possible way to have the virus spread quickly yet be deadly is to have a double effect. Shortly after infection, it basically acts like the common cold. The common cold spreads quite effectively ...
If you want a "realistic" time travel "anyone" could plausibly do, you will have to look at the gaps in modern physics. New Scientist magazine (out of the UK) recently listed 11 things modern physi...
Allow me to introduce you to the Cosmological Principle. According to this, the universe looks the same everywhere, from wherever one stands, and in whatever direction one looks. After all, our p...
To answer the question directly; I don't think it is possible "intelligence" was "brought" by anything; as an earlier answer details, the evidence is overwhelming that intelligence arose slowly ove...
I know you (the OP) have settled on commercial reasons; but in reading the setup I imagine privacy and/or military advantage could be at stake. The inhospitable environment make for a natural "moat...
There is plenty of material in the earlier answers to make them nearly comprehensive; so while I agree with those earlier answers, I will only expand on a devil's advocate view for the fun of it: ...
Yes, it's been tried. Hashizume et al. attempted to use semiconductors (variants of which are also used in normal solar cells) which were subjected to gamma radiation from a radioactive isotope of...
There is only one possible route; which I will describe below, but otherwise your conditions make the task impossible; unless "largely indistinguishable" means "difficult but not impossible" to dis...
All right, let's look at this from a geometric point of view. As seen from Earth, the Sun subtends anywhere between 31.6 and 32.7 minutes of arc in diameter. The area enclosed by a circle (ellipse...
I'd say, kill some small percentage of the children, too, like 20%: Say any and all women that are pregnant when they are first exposed to the disease, pass it on to their fetus; but the immune sys...
You want a cold disk. Mercury is an example of a volatile, which, for our purposes, means that it exists as a solid only at very low temperatures. One thesis (Funk (2015)) classifies it as "modera...
Obviously you need stable orbits long enough for evolutionary forces to take effect (millions of years), but clearly that could be possible with a large moon and some smaller moons; to emphasize th...
Short answer You have the two equations you need on the linked page under the heading "Stage two": $$r_i=\sqrt{\frac{L_{\text{star}}}{1.1}},\quad r_o=\sqrt{\frac{L_{\text{star}}}{0.53}}$$ where $r...
Let's assume that the Moon is roughly a black body. Therefore, its luminosity can be approximated by the Stefan-Boltzmann law: $$L=4\pi\sigma R^2T^4$$ As you've said, $T=1100^\circ\text{ C}=1373\te...
On Earth, escape velocity is about 11 km/s, or 11,000 m/s. Assuming the opponent weighs around 70 kg (maybe more), that's a kinetic energy of at least $$\text{KE}=\frac{1}{2}mv^2=\frac{1}{2}\cdot70...
