Tar_Alcaran

But if you ignore timezones, you could stop a clock at noon, and just fly around the earth keeping the sun dead above you.

The history of timekeeping is pretty interesting in itself.

In ye-olde-days before everyone had clock most of europe had flexible time. sunrise is at 6am, noon is when the sun is heighest, and sunset is at 6pm. 9 am is between soon and sunrise. Obviously that means during winter, an hour in the night is longer than an hour during the day, but nobody really cares about that anyway.

Then we got clocks, and they would generally be the church bell. So everywhere in hearing range of the church had a single timezone, whose accuracy would depend mostly on the clock they had and they’d synchronise that with noon occasionally. Of course, that clock would say something else from the old system. Sunrise is at 6 in the morning, or at 7.32 “on the clock” (o’clock). Of course most old clocks didn’t have minute hands, or were in any way external, so it would be “roughly half past seven” at best.

The old system of church time turned into railroad time, and there are amazing paintings and photographs and museum pieces of a station that had 3 clocks: its own time, and the time of the next station in either direction. By this time, almost nobody nobody used the old “split daytime in 12” system anymore.

But then countries started to think they really needed to synchronise their timezone. So most countries picked a big church either in the capital or in a big city in the middle of the country and declared that to be the time in their country. The Netherlands, for example, decided in 1909 that they like GMT +0h 19m 32s and 13milliseconds. Germany picked GMT +1h. The Netherlands realized this was stupid in 1937 and moved to GMT +20m, for a very short time. Of course, the fact that a national time existed didn’t stop many cities from sticking to railway time anyway, and for a short time, everyone had 2 different times again (if you didn’t live in the capital).

And then between 1938 and 1940, basically all of europe was… motivated… to pick one timezone, which just happened to be the German one, and we stuck to it ever since.

And more

I picked up a pair of xiaomi redmi buds 5. They’re like 30 bucks, and they meet all your requirements! They have an app, but it’s only a requirement if you want to custom configure the noise-cancelling, voice passthrough, etc etc. They just plain work over bluetooth without an app. The tips are silicon rubber and it comes with 3 sizes, so they’re replacable

Ignoring air resistance (which you really shouldn’t, especially not when you’re talking in the thousands of meters per second), you need to launch something at around 1400m/s get it to 100km high “suborbital”. You need to launch it over 8000m/s to get it into orbit. In 2022, Spinlaunch were getting to ~450m/s, but that was two years ago and maybe they’ve improved.

Now, 1400m/s is in the neighborhood of a tank cannon, which is doable. But 8000m/s on the surface, or about 29.000 kph, is about mach 23. That’s like running smack into a brick wall of air, every millisecond. And in reality, you need MUCH more speed, because you’re shooting at a much shallower angle, so there’s a lot more air to get through.