The entire Earth should go Metric

The United States of America is one of 3 countries not using the metric system.

Who enjoys converting miles to feet? Gallons to cups to tablespoons to teaspoons? Tons to pounds to ounces? Speaking of ounces, are you referring to volume or weight? When you say weight, do you really mean mass or weight? In the metric system grams is mass, newtons is force (weight being force due to gravity.)

The word cup can be confusing. Do you mean just a drinking container of an unspecified size, or do you mean 8 ounces?

At least the meter is based on the measurement of the Earth and not some random person's foot! Halfway around the Earth is 20 mega-meters. Even the British abandoned the British system for the French! Feet, miles are in-congruent. Who wants to memorize 5280 in a statute mile? Then you got your 6075 feet per nautical mile to pile onto that. There are 1000 millimeters in 1 meter, there are 1000 meters in 1 kilometer, very simple.

Sure app and search engines will convert, but when you got oil on your hands when cooking do you really want to play with an app on the phone to know how to convert tablespoons to teaspoons? (maybe ask a voice assistant, but if it's loud it probably won't understand you) With metric it's easy to deal with with conversions in your head. 1000ml in a liter, 1000g in a kg, for example. I don't want to remember how many cups in a gallon!

Also the entire Earth should go full metric, km/h isn't much better than mph. You still gotta deal with that unwieldy 3600 second value. Meters per second would be ideal. Say you're travelling at 10 meters/sec (22.3mph) and you have to travel 10 kilometers. Simply divide 10,000 by 10 = 1000 seconds (16.7 minutes). Say you were going 36km/h, how long will it take to travel 10 kilometers? Not readily apparent, gotta do something like 10/36 to get hours, then times that by 60 to get minutes. We should just get rid of hours and minutes and stick with seconds and kilo-seconds to make it even simpler, 86.4 kilo seconds per day.

Related links
http://kilosecond.info/

A better explanation of lift of an airfoil

-Air never leaves the flat bottom, hence it always gets pushed upward, known as lift.
-Drag is air pushing upon the leading edge, bending around it.
-The key is the lack of air on top to apply down pressure.

The reason is that the airfoil traveling above a certain speed causes the following:
-After being displaced by the leading edge air doesn't travel back down to the top surface faster than the top surface tapers downward. Therefore it is unable to apply pressure. It's that simple.

I've heard explanations saying low pressure on top due to higher velocity that is due to farther distance to travel. While those conditions might be true, that does not properly explain the phenomenon.

Airfoils depend on air pressure, going through unpressurized air wouldn't yield any lift (if you could somehow get unpressurized air to stay put that is.)

Precision and accuracy

So many people don't understand that these are fundamentally different aspects.

-Precision is basically how many significant digits, or how many digits right of the radix point.
-Accuracy is how close the measurement is to a target value.

For example:

Dale's discus throw was measured PRECISELY at 36.821 meters.
Bob's discus throw was measured at around 50 meters, plus or minus 2 meters.

Since the target was 50 meters Bob's throw was more ACCURATE than Dales.

Maybe time should just be sub solar longitude

It's very easy to convert UTC time to sub solar longitude (longitude where the Sun is directly over)

0000hrs UTC the Sun is directly over the ante meridian (180deg lon)
1200hrs UTC the Sun is directly over the prime meridian (0deg lon)

Every 30 deg longitude is 2 hrs (hence every 90deg is 6 hrs)

Why not just denote time as sub solar longitude? One can easily compare local longitude with sub solar longitude to figure where the Sun will be located.

Universal time of day: should be the longitude of the sub solar point.
Time of year should be latitude of sub solar point.

Links
https://en.wikipedia.org/wiki/180th_meridian
https://en.wikipedia.org/wiki/Prime_meridian
https://en.wikipedia.org/wiki/Coordinated_Universal_Time

Fish eye lens would offer no distortion on spherical displays

Fish eye lens would offer no distortion on spherical displays, the problem is the lack of spherical displays! We're stuck with flat rectangular displays.

https://www.youtube.com/watch?v=7dtH6uKj-QI
https://www.youtube.com/watch?v=a2e9noEg1zg