No, the Earth's magnetic field is too weak to affect the operation of devices that use magnetic forces. If it disappears or reverses, things will work fine.

> most navigational systems use some version of GPS, which aligns through satellites rather than magnetic compass

Actually no, compass and GPS can't substitute for one another. GPS tells you your location, but not your orientation. If you are standing still, GPS won't tell you which direction you are facing (or which way the front of your vehicle is pointing), but a compass can.

If you are moving, GPS can tell you which direction you are moving, but on ships, airplanes and spacecraft, the direction you are moving is not necessarily the direction your vehicle is pointing. So you still need a compass. A gyroscope also works for this, but gyroscopes drift over time, so a magnetic compass is a more accurate long-term reference.

Spacecraft often use star trackers or sun sensors for determining the orientation (attitude), but some do use magnetic sensors. And also, most satellites rely on magnetic torquers to change their attitude. Reaction wheels (aka flywheels or gyroscopes) are also used, but they eventually saturate (moving as fast as they can) and eventually they need to offload the angular momentum to something external. That something is usually a magnetic torquer, which is an electromagnet that basically pushes against the Earth's magnetic field to rotate the spacecraft. Thrusters also work for this purpose, magnetic torquers are far simpler and cheaper, so most satellites in low orbit just has magnetic torquers, not thrusters.

Undergraduate degree is also called a Bachelor's degree. It's your standard college degree.

After you get your undergraduate degree, you can then go to a "graduate school" to get a more specialized education. And after many years in graduate school you get a graduate degree such as a Master's degree or a doctoral degree (Ph.D).

OP needs to clarify if they mean one engine in the middle of the vertical stabilizer (e.g. Lockheed L-1011), or two engines at the tail of the aircraft (e.g. MD-80). Though some have both (e.g. Boeing 727).

If you want an odd number of engines on aircraft, one of the engines need to be in the middle of the aircraft. So the middle of the vertical stabilizer is a good place. This design made sense back when 2-engine airliners were not allowed to fly overseas routes, but 4 engines became expensive, so they opted for 3 engines. More recently, some small jets have a single engine, and at least one design (PiperJet) was developed with an engine in the vertical stabilizer.

I said county, not country.

Each state contains areas with very different demographics and laws. How about plotting data by county?

We do see it, mainly in the form of flooding from storms. The flooding is worse because the sea level is high to begin with, and you've got storm surges etc. on top of that. Many coastal cities are building flood barriers.

This exactly, but also, GPUs are optimized for FLOATING POINT matrix calculations, as opposed to integers. To over-simplify, floating numbers are like the scientific notation for numbers.

Europe has a limit on the total length of the truck+trailer. So a shorter cab allows for a longer trailer. The US has a limit on the length of the trailer, but not the cab, so the cab can be as long as you want. And a longer cab allows for better aerodynamics and more room inside, which is especially important for American long-haul trucks because most drivers live in the cab.

Right now, in most parts of the world, there isn't an actual shortage of fresh water. The problem is managing and distributing the water that is available there, and managing the usage. So it's generally cheaper to buy & transport water, or reduce usage, than to build and operate a desalination plant. There are some exceptions, like some newly built cities in the Middle East.

3.5mm earphone jacks have been standard for ages though - the original Sony Walkman (released in 1979) already had it. My understanding is that the airline industry deliberately chose a different connector so people won't steal the headphones. Then later, they switched to 3.5mm when headphones became dirt cheap and not worth stealing.

Actually, ashtrays are required on all airliners. So if someone decided to break the law and smoke, at least they won't set fire to the trashcan.

That's a choice we made, to build things far apart and connect them with roads rather than building walkable / bikable cities.

Cowboy Bebop has hyperspace travel ("astral gate"). It's not clear if it's FTL, but if it is, I'm pretty confident it would never happen.

Infrared cameras measure the temperature by measuring the amount of infrared radiation emitted by a surface. But metal surfaces inherently emit less (it had low emissivity) so the infrared camera reads low. Try putting a temperature sensor (RTD, thermistor or thermocouple) on the metal and it should read 105C. Or put a dab of paint or piece of tape on the metal and aim the IR camera at that.

Tidal friction is caused by the planet's rotation. The tidal force deform the planet, and the rotation drags the deformed shape to be misaligned with the moon.

If they are tidally locked, there won't be any tidal friction, would there?

I just didn't understand your edited comments.

I don't think the "clear the orbit" criterion refers to a moon or double planet situation. It just means there isn't another big thing orbiting the star at the same distance. I don't know what shiggles and whatshingles are.

I think it's possible. Robert L. Forward was a physicist and wrote a novel called Rocheworld which depicted such a world.

I don't get it. How exactly does the inverse square law tie into this specific case?

The point was to get to outer planets within a reasonable amount of time, carrying a useful amount of science intruments. Also it has gained speed through gravitational assist.

The New Horizons probe is much more recent, and designed to get to Pluto within a reasonable amount of time. It still took 9 years, and it's actually traveling slower than Voyager now because it's had fewer encounters with planets, and therefore benefitted less from gravitational assist.

1. There aren't any nearby black holes.
2. We don't have the technology to send a probe to any black hole. We don't even have the technology to send a probe to another star, and the closest black holes are hundreds of times further still.
3. Any probe we send near a black hole will be ripped to shreds by the tidal force. (Unless maybe if it's a supermassive black hole, but I think the closest one is at the center of our Galaxy which is 28,000 light-years away.)
4. Even if we had the technology to send an interstellar probe, it would be a lot more valuable to send it to star systems with potentially habitable planets, or star-forming regions, or maybe a newly formed star with a protoplanetary disk, or maybe a really old globular cluster, or a late stage star that may go supernova any time, etc, etc.

It's not a matter of "taking chances." We don't have the technology to send a probe to even the closest stars (other than our Sun). And the closest black hole is hundreds of times further away than the closest stars.

A tuning fork would not vibrate measuralby faster in vacuum. If air resistance changed its vibration frequency (pitch) by a measurable amount, it would also vibrate slower when its vibration amplitude is less - i.e. its pitch would go down as the vibration decays.