71

I am going to claim expertise on this issue for a major reason: I live in the Arctic. I've also participated in search and rescues in the Arctic. The basic answer to this is that small groups of sufficiently-prepared people actively trying to evade detection and if no one is specifically looking for them can do it trivially by any number of means. It's hard ...


16

GH1 gene If the GH1 gene has problems in a person, this person will likely be much shorter because of a lack of growth hormone. Smaller people consume fewer calories when idle (but more to walk the same distance as a tall person). So this could help in reducing global calorie intake if accompanied by other measures to diminish the need for physical effort (...


10

What you want to do is to decrease basal metabolic rate for humans. It is influenced by several factors, I just went through them one by one and came up with several ideas. Reduce physical activity Everyone goes to sleep About 30% of BMR comes from physical activity, thermoregulation and digestion: About 20% of one's energy expenditure comes from ...


9

Consider different parts of the globe, in the real world. Illegal immigrants are trying to walk across quite inhospitable terrain at the US southern border. Some are caught, many get through. Illegal immigrants are trying to cross the Mediterranean on small watercraft. For some, the goal is to be rescued by ships which do not return them to Africa. For ...


9

Depends on how good of a chemist your time traveler is. While the purification methods on many of the needed materials were not discovered until the 1900s a good chemist, craftsman, and historian could go back further to the discovery of the ores he needs. To make the alloy you will need Iron, Titanium, Vanadium, and Aluminum: Iron has been around for ~...


8

With a nuclear reactor there is almost unlimited energy to mechanically push against the ring objects, so infinite delta V. Weeeeell... yes and no. Your reactor fuel isn't infinite, for one thing. More importantly though, your ability to accelerate is likely to be heavily influenced by your choice of reaction mass. You'll want to be throwing it away from ...


8

There's some ambiguity in the question - the title says "has the feedstock" but doesn't indicate whether that's ore, refined metals, or "can get to places where the ore can be found". Assuming it's the first option, ore: Probably Around 1900 AlexP's comment is valid, but if your time traveller has Future Wikipedia downloaded into his phone-analogue, all ...


7

Electromagnetic or magnetic induction is the production of an electromotive force (i.e., voltage) across an electrical conductor in a changing magnetic field. This is correct, but the operative word here is "changing". Specifically, Faraday's law states $$\nabla \times \mathbf{E} = - \frac{\partial \mathbf{B}}{\partial t}$$ If you're not familiar with ...


6

I'm going to open the bidding with S1 Steel covered by ISO 4957 Rather than being cutting edge science, this is a commercial product. Specifically a shock resistant cold work tool steel. Medium carbon with tungsten and chromium. Ideal for weapons and likely armour as well. Specifically resistant to losing edge and deforming under repeated high impact while ...


5

In short, you can either decrease the minimum energy the body needs to function through thyroid hormone reduction, or increase the amount of energy you get from breathing by artificially upping respiration rates. Anything that affects thyroid hormones will affect how much energy your body needs to function. For the thyroid. Medication: Thiamazole. Gene ...


5

Yes it could be out of plane Astronomers are reporting today the discovery of a planetary system way out of tilt, where the orbits of two planets are at a steep angle to each other. This surprising finding will impact theories of how multi-planet systems evolve, and it shows that some violent events can happen to disrupt planets' orbits after a planetary ...


5

I agree with other answers that going by land through Alaska and Siberia and crossing the Bearing Strait at a relatively narrow point might be much better for your invaders than crossing hundreds or thousand of kilometers or miles of the Arctic Ocean. Crossing the Arctic Ocean can be quite dangerous. If they cross in groups using dogsleds they will have ...


3

As the previous answer mention it, it will be easier by Bering Straights. I don't think they can go "undetected" but group from 4 to 5 may go unnoticed (they will be seen, but it will not be seen as a unsual thing). Here you can go by remote terrestrial areas where it may be easier to hide in case of a recon flight, than on the ice sheep. But if there are ...


3

Depleted Uranium : for Flails, Two-Handed Hammers/Swords, and Shields For a swung weapon, mass is the reservoir in which the kinetic energy of a swing or a horse's charge is stored. This reserve of kinetic energy is what tries to foil potential energy reservoir of the target's yield strength times the strain. A high momentum hit will daze the other guy, ...


3

If there are some gas giants, the things will evolve pretty quickly towards an ecliptic plane - tidal forces will dissipate the energy fast enough to get the system evolving to a maximum moment of inertia with the minimum kinetic energy. Rocky planets orbiting far from the gas giants may persist longer on inclined orbits, but eventually will fall "in line". ...


3

Cocaine is well known for having, among the short term effects, a reduction of the sense of hunger. I wasn't able to find the corresponding section in the English version of Wikipedia, so I quote the Italin version, which states Gli effetti neuropsichiatrici sono estremamente vari: Distorsione cognitiva e delle capacità recettive sensazione di ...


2

Brain Hog/Fog Well, you said "survive", and not "thrive", so run-of-the-mill starvation will solve your problem nicely. Others have observed that muscle mass has high BMR, which is why atrophying muscle is one of the first things the body does in response to starvation. But the single hands-down winner for specific energy consumption is the brain. It ...


2

No need to introduce a new one. Eris is the goddess of discord. She discords of other gods so much that her planet has an orbital inclination of 44.1444 degrees. She doesn't want to orbit in the same plane as other planets. Makemake and Haumea hace inclinations of 28 degrees, for consideration. The trick here is that those three planets are way far from ...


2

This is already happening See Unified Weapons Master Metal in the armour will be limited to a thin outer layer for appearances only with the inner layers being carbon fiber and impact foam. Sure it'd be nice to see more metal but really knights won't use that much and the sponsorship logos on the shield will sell more. At the end of the day you have two ...


2

You asked "Is there any way to calculate it?". The answer is yes, but it's not going to be as simple as plugging a few numbers into a simple formula. You'll need a general circulation model. The reason is that the heat transport around the planet involves the atmosphere and the oceans, and these require dealing with fluid dynamics. This is going to bring ...


1

@M_A_Golding notes: An objective outside observer might consider orcas and other cetaceans to be intelligent beings This suggests another possibility. If you can engineer "humans" with alien minds, why not whales? Then your near-humans could collaborate with these near-whales to cross oceans somewhere warmer (or not, if they have sufficient protective ...


1

There was a report some time ago about a planetary system where there was no ecliptic plane: some planets were as off as 60 degrees from the orbital plane of the others (I don't remember the exact value by heart) That can happen if you have no medium to dissipate momentum.


1

There are many uncertain variables with your question. One being scale, how many solar cells are needed per year and at what efficiency? It is reasonable to presume that existing technology could be miniaturised sufficiently to enable small scale production of solar cells with fairly modest means. The technology is mature and well understood. Processes ...


1

If you don't want steel Aluminium and titanium are your best bets. For armor there are aluminum-steel alloys and titanium alloys. Making armor lighter is the biggest benefit you can gain. For more minor alloying components nickel improves both strength and corrosion resistance of steel. If you aren't restricted to just improving the metal parts of the ...


1

A mistake you may be making here is that it's not a scientific hypothesis the main character is trying to prove. Rather, you're trying to prove a historical fact about something(s) that happened or didn't happen. The whole idea of the supernatural, or miraculous, is that it isn't natural. Let's say that the main character has observed objects levitating ...


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