26

The problem is not the sounds the goblins make. Since the goblins need to move around (and probably breath as well), they will be moving through a gaseous medium. That is much less dense than rock, and will easily be detected when analyzing seismic waves (even the ones with epicenters far from the Goblin city). Seismic waves, like any other wave, refract ...


23

It's worth noting that one of the proposed Mars rovers (for the Pathfinder mission in 1995) was a quad-track: I haven't been able to find out much about this rover design, so if anyone knows who built it, or has more information, I'd really like to know more. Rather curiously you'll notice that this particular machine doesn't have any idlers or boogies ...


18

Redundancy. A tread is a single body, and if it's severed, the entire drive unit is useless. If that's your only drive unit on one side, all you can do is spin in circles and you're done for. If you still have one active drive unit on that side, you may have some mobility remaining to retreat or regain formation with your allies. (The Spirit rover is an ...


10

Hoover Dam is a fine dam. Use it for that. Long before there was hydroelectric power, people dammed waterways to create reservoirs. That function of the Hoover Dam will work fine even as the hydroelectric machinery becomes nonfunctional. There is nearly a square mile of flat desert in the wash leading up to Boulder Beach - circled. You could irrigate ...


7

Methinks they'd be detected Seismometers are by definition extremely sensitive, recording all that is going on around them whether seismic or not. (Source) Considering seismometers can accurately detect small things miles away, the answer is most certainly "no." It's theoretically possible that the goblins could set up a random pattern (like ...


6

Was the dam hit? It would have made the list as a counter-value target during the Cold War days, but there are fewer weapons for any attacker these days. (Call it Russia? The Chinese have fewer missiles, not enough for a nuclear holocaust) Does the machinery last without maintenance? The electrical generators need regular maintenance, and the article says ...


6

There is one other niche purpose for large split track vehicles. They are fairly common in large agricultural tractors. Track use in large tractors has come about for the same purpose as load distribution mentioned in ksbes answer. Tilled soil can be soft and loose, but it is also in the farmer's interest to avoid compaction of the soils (which can adversely ...


6

"The Goblin Caves are a protected scientific site of incalculable geological, paleological and anthropoligical interest. They contain the remains of an early human settlement; scientific exploration must be carried out with painstaking caution to prevent any valuable finds being destroyed. To this end, the caves have been sealed and the Committee is ...


5

Anywhere there are natural caves, AKA IN PLAIN SIGHT: I would think that anywhere there are natural caves, geologists would see the caves, but not think twice about them. There are HUGE cave complexes around the world, and humans can tell they are there, but not do a thing about them. "Say, students, did you know the ground half a mile under the city is ...


5

Half life Nuclear weapons and nuclear power plants use very different material for their nuclear reactions. A nuke needs stable material that can be pushed over the edge, using as much of the material as possible for maximum efficiency. Power plants use a material that can be less stable for ease of starting a reaction, and needs to more slowly react for a ...


5

I drive one of these quad-tracked tractors. When carrying a lifeboat the total weight is over 56,000kg and it is able to do 16km/h over flat ground with that load. The suspension has no springs, but due to the vehicles articulation and all four tracks being hydraulically powered and able to independently tilt to match the terrain, it is amazingly capable for ...


4

Towards the end of the Soviet Union, there were many experimental tank and AFV designs in an attempt to gain decisive superiority over rapidly advancing Western AFV's. One common feature in these designs was the proposal to use 152mm cannon to deliver massive amounts of kinetic energy against even heavily armoured Western tanks carrying composite armour, as ...


4

There are indeed some advantages to having multiple treads. One big advantage is in the geometry. With two treads, the tank's pitch (the angle between the vehicle's nose and the horizontal) is on a line tangent to the ground underneath the vehicle's center of mass. On mostly level ground, this means nothing. When the ground changes elevation suddenly, ...


4

Bioweapons might be better for lasting trouble. Nuclear war is a good way to wreck everything fast. But radioactivity fades, and especially outside with wind and water and life working on the particles, environmental contamination will be gone in decades or if not gone, diluted to harmless imperceptibility. The Chernobyl experience has demonstrated how ...


3

Depends So, all infections and therefore all antibodies are not equal. There are a few talking points to discuss about this question. Saying that you "have antibodies" is an incomplete statement. If your body is able to learn how to create antibodies for an infection, many people then say that you "have antibodies" and should never be ...


3

It would make them both safer Generally speaking (that's important!), antibodies do not grant immunity. They grant resistance. If enough people enjoy that resistance then society becomes immune ("herd immunity"). Diseases like polio, scarlet fever, and measles were declared overcome due to so many having the antibodies and didn't start to rear ...


3

Yes, the fetus would be protected by maternal antibodies. https://en.wikipedia.org/wiki/Passive_immunity is immunity of a fetus or newborn by virtue of maternal antibodies. These antibodies cross the placenta. They persist in the newborn for a time after birth. Passive immunity is the transfer of active humoral immunity of ready-made antibodies. Passive ...


3

Ask nicely Although television might suggest otherwise, a government's first reaction is to ask nicely for cooperation. Hunting down such people is counterproductive. You either kill them, wasting any potential, or antagonise a powerful individual, making him/her a risk for your highly trained personnel, the public at large and structures. On the other side, ...


2

No, unless you can justify why no nukes fell anywhere near Las Vegas Hoover Dam, like all hydroelectric dams, uses turbines—big copper-wire-wound generators. Which makes them horrifically (and catastrophically) susceptible to the electromagnetic pulse of a nuclear detonation. It wouldn't even have to be close, but it will be close nonetheless due to Nellis ...


2

It is quite impractical for all-terrain vehicle. What is tread is used for? - to support high load on soft surface. It means one of two things if any of this treads fails for any reason - there is no enough suppourt for high load on this side/coner and vehicle losses ability to move. Since 4 tracks are times more prone to falure in one of them - they a ...


2

One of the main issues of a head connected to the back of the skull is that the part of the neck doing most of work to keep it from pending to the ground is the muscles rather than the bones. Because of this arrangement, the skull has a smaller max weight limit than if it relied more on the bones to sustain it (position yourself in a horizontal position ...


2

YES, BUT... You could make this be the way you want, if that is what you want. I'd disagree that everything CAN'T be a generalist in a world where nothing is stable, but it's your world. If the genes for surviving in each biome exist in all individuals, then you can trigger them whenever you want. A guy wandering into the mountains can have his lungs change ...


2

Duck tape is like The Force, it as a dark side and a light side and holds the universe together. The cause is clearly Midichlorians


2

All kinds. They grow an enormous array of different plants from all over the world. All the food plants the founders could get, and also loads of medicinal and culinary herbs. And flowers which are grown just because they are beautiful and the founders worried beauty would go out of the world. Your bunkers are not some grimy burrow with people scraping by ...


1

Not really hide, but they could set up, around the city, a suitable meta-structure to diffract seismic waves around the city, instead of having them bounce off its interfaces. The same way a stealth airplane scatters radar waves away from the direction where the radar is firing them, the underground city might use a structure with proper refraction index ...


1

Other answers have given good reasons why caverns under Los Angeles would be detected. A second part of the question would be whether there were any cities where the caverns might go undetected. It might be easier for something like this to go undetected in a city like Paris or Johannesburg, which is built on top of a large network of former mines. Although ...


1

There are people who know about the goblins. But it is not publicized. Besides goblins there are other very good reasons for humans not to start poking around the underworld. The party line given to geologists and seismographers is that there is an acoustically reflective layer beneath the city, which turns out to be true and experimentally demonstrable ...


1

Hormones. No, seriously. The vampires don't need blood to live, they need blood because they're junkies. The vampires inject a venom that acts an anesthetic, but they have conscious control over it, so they can cause the bite to seem painless and even euphoric, or withold it and be as painful as it really is. As a result the victim's body responds in kind, ...


1

Vampire physiology Vampire teeth are hollow. It is not generally known that, via a system of heart-like valves, the victim's blood does not enter stomach but goes directly into the vampire's bloodstream. Of course a sudden influx of blood has to go somewhere and the vampire has various organs that can expand to accommodate it. One such organ is of course ...


1

THERE ARE (at least) TWO CASES. SEE! Case 1: The universe has the same universal constants et cetera as ours. It just happens to have no matter in it. In this case jumping into the new universe would be similar to jumping into outer space. Darker sure. But with no additional hazards or risks of sudden existence failure. Case 2: The universe has a different ...


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