Imagine someone who's really bad at playing Tetris. They don't even try to make the blocks fit together well and they make lots of big empty holes in their pile of blocks as the blocks get stuck on each other in the least compact way possible. That makes their pile get high very quickly.

That's what a pile of snow is like. Raindrops are excellent at playing Tetris because liquids will change shape as needed to fill the lowest possible level of the container. Snowflakes on the other hand won't. Their very spread-out shapes, fully of spiky bits at the ends, cannot tessellate.

Snow depth is made mostly of the air gaps in between the flakes that get hung up on each other's spikes.

You sort of answered it yourself with this phrase:

"about 8 years".

Is there an elected position with a term that long? Probably not. Mayor, Alderman, etc - they all have shorter terms.

That means you are asking elected officials to invest in infrastructure that doesn't pay off until they're out of office and their successor gets to take the credit for it. A lot of political damage comes from the wrong politician being blamed/credited for things where the cause and effect occur more than 1 term apart on the timeline.

Largely because it's super easy to play it informally in pretty much every poor village in the world.

1 - You don't need expensive gear. Just a patch of ground, one ball, and some stuff to drop on the ground to mark the goals.

2 - You don't need the full complement of players. While the official rules require exactly 11 players per side, you can cobble together an informal game with whatever smaller number of people you have available. (Compare with something like baseball, where the pitcher, catcher, infielders, and outfielders are significantly different jobs where people can't easily overlap between them so you need people at each position.)

This makes it so that poor countries actually have a shot on the world stage. Just because you grew up in a poor village doesn't mean you didn't get to spend a lot of time playing and practicing as a kid.

It's because using air drag to slow you down saves enormously on payload fuel mass.

If you are coming down near Earth from a very high position, you will sweep by the Earth going way too fast to stay in low earth orbit. You'll just fling past Earth and rise up high again. So if you want to dock with something in low earth orbit, like the ISS, you have to decelerate a lot. That excess speed has to be removed to slow you down into a relatively circular orbit at low altitude.

And if you are going to do that decelerating in space, not touching the atmosphere, you have to provide all the deceleration yourself. With your own fuel.

But if you pass really low to Earth, so you are scraping the atmosphere, then the atmospheric drag can provide all the deceleration you need without you having to spend fuel doing it yourself. Granted, that means you need protection from the heating effects of the pressure shock, but if you can handle that heat you gain the advantage of needing no propulsion to decelerate with - that means not needing a powerful engine and not needing fuel for that powerful engine.

Merely having a very small bit of fuel for a little steering engine that can merely slightly deflect your path is sufficient. All you have to do is slightly bend your path long before you get to Earth, to ensure you hit the atmosphere just right. That's more of a computing challenge than a delta-V challenge.

And you don't even need to put that computing power on the probe itself. You can have the probe have just enough smarts to obey any maneuver command you send it, and then use more powerful computers on Earth to calculate the needed maneuver to beam to the probe. (This is basically how they did this sort of thing in the 70's when the math required room-sized computers.)

I didn't cover it yet, but if you try to do your own self-propelled deceleration to turn a high-speed Earth flyby into a low Earth orbit, it's not sufficient to have a little bitty weak steering engine. You need to ensure that engine has a significant level of thrust because it doesn't just need to spend a lot of delta-V, it has to spend it fast. If it's one of these super-efficient but also super slow engine designs, such as a weak little ion engine, the probe won't slow down fast enough and will slingshot past the Earth back up to a high altitude before it has caused enough delta V to do much.

tl;dr - Needing a heat shielding arrangement for the bit where the probe hits atmosphere hard does add a little bit of mass, but not nearly as much mass as it would take to have a high-thrust engine and the fuel to run it so you can provide that deceleration yourself.

And since we're talking about the mass at the very end of the mission, in the final payload that comes home, that's mass you have to carry at the tip of the rocket through all the stages along the way. The very last stage of the mission is the most important place to save on mass. 1 kg more mass in the final stage can mean more tonnes of mass added across the other stages that come before it.

I never played Halo and don't know the game lore, so I can't really answer the question - I don't know what halo rings are supposed to be.

Even if you had such a fantasy strong material to build it from, a rigid ring doesn't have a stable orbit. Once the tiniest thing knocks it slightly off center, like a single meteor impact, or even the gravity of a passing meteor that doesn't even hit it, the ring would quickly shift further and further off center until one side hits the planet. The orbit isn't self-correcting once you make the object rigid. Quite the opposite - whichever side is closer to the planet gets a stronger pull that pulls it even closer to the planet.

If you wonder why that doesn't happen to individual orbiting satellites, that's because individual orbiting objects that are knocked closer the the planet take on an eccentric elliptical orbit shape which is still stable. But a rigid ring is still stuck in a circle shape even when the "proper" orbit that would remain stable should be an eccentric ellipse.

This raises an interesting question of whether a ringworld that was flexible such that it could be deformed into any ellipse could keep a stable orbit. It still probably couldn't because the same energy orbit that was a circle, when it deforms into an ellipse, ends up being an ellipse with a larger circumference than it had as a circle - so it would have to be both infinitely flexible and infinitely stretchy. That's why a field of rocks and dust can form a stable orbit ring shape (they can form a shape that is infinitely flexible and stretchy since they're not really one joined object.) While a single-object ring really can't.

If you work out the math, it turns out a solid circular ring around a gravity well, while it can be in equilibrium, it's not in stable equilibrium. It's in unstable equilibrium. This means once it forms it's not going to be staying that way. The slightest tiniest offcenter effect, including the teeny peterbations from other planets in the solar system, will knock it off center and once that happens the orbit will degrade quickly, until one side of the ring gets closer and closer and hits the parent planet.

In order for the orbit of a ring to be a stable orbit, the material that makes up the ring MUST NOT behave like a single solid rigid object. It has to behave like separate particles each in their own individual orbit. Thus a ring of dust or a ring of rocks works, but something like Larry Niven's Ringworld does not.

(This became a major plot point addressed in the second book in the series, where after being told by fans that the Ringworld as he envisioned it wouldn't stay in orbit, The author invented the notion that the ring was artificially stabilized by having been built with ramjet thrusters along the rim that would constantly turn the solar wind into propulsion thrusting back at the sun. So the closer the ring got to the sun the stronger those thrusters would work, pushing back away from the sun, automatically stabalizing what would otherwise be an unstable system.)

Look on a map where Lake Superior touches a little bit of Wisconsin. There's some islands there. Its one of them.

If you look at it on google maps there's a bit of "street view" coverage along the north shore of the island that's really actually more "boat view". You can see how rocky the shore is from that.

It has to do with this difference in history:

US states: They were someone else's colonies right up until the point they were collected together into a group called the United States and only then did they stop being colonies and start self-governing.

UK internal pieces: Had a history of having been independent countries already, prior to being collected together into a group called the United Kingdom. That historical difference - that they were once self-contained countries while the US states never had such a period of history - causes the difference.

The formation of the UK was "Here's some independent countries that border each other and compete for space on this island so they have wars against each other. Instead of warring all the time maybe they can just agree to share this island by joining into one nation." (Yes, I know Northern Ireland is on a different island, but that got added to the UK later.)

First you have to understand how it was originally used, then understand what replaced it, then you can understand why it's not used anymore.

The ability to skip ahead or skip back to a different line of code lets you do a great many things. It's generic and open-ended what it can do. When you create a way to do it conditionally where it won't always execute the goto then it allows for all the standard flows we use today.

An If-block is really just "If this condition isn't true then GOTO the spot just past this block so you skip over it."

An unconditional loop is really just "GOTO a previous line up above so you start executing all this stuff again. When you get back down to this line, GOTO the top again. Repeat."

A conditional loop is really just "IF the thing we're checking for to end the loop isn't true, then GOTO a previous line and run that stuff again."

It's versatile. It can form just about any pattern.

So what's the problem? Well that versatility IS the problem. To understand why a programmer put a GOTO there, to understand what they were trying to do, you have to analyze a lot more lines of code to see what the pattern was. Because a GOTO could really be for a wide variety of purposes. It might be part of an IF. It might be part of a WHILE (thing is true) loop. It might be part of an UNTIL (thing is false) loop. It might be part of a counting loop (FOR loop). It might be to just jump over to a subroutine and return from it.

It's not visually obvious from just looking at it what it's for. You have to trace the code line by line before you can see the big zoomed-out picture of the layout.

It also allowed unique flow patterns that don't fit into one of the commonly known patterns. A clever programmer could have been using it to do something unique that only makes sense in their own mind and doesn't make sense to anyone else.

So, essentially, it can make the program hard to understand, which then means programmers make mistakes when editing it.

The fix was to find all the common things people were using GOTO to do, and create special keywords for those patterns and replace the use of GOTO with those new terms. So you can still do all the same stuff, but in a more descriptive way that actually says what you're doing. You don't have to guess "Which of the 8 or 9 different reasons for using a GOTO might this one be?" when it uses a word like WHILE or FOR or IF that actually tells you which one it is.

But the interesting thing is... under the hood, it's still really all GOTO. At the lower machine language level, you have the various JUMP instructions, which are exactly what a "GOTO" would have compiled into, and as it turns out, is also what the newer words like WHILE and FOR and IF also still compile into.

Under the hood, it's still all GOTO. But now it has more descriptive ways to summarize those GOTOs into human-readable structures.

There are two ways programs try to identify the format of a file.

One is to just naively trust the extension. This can sometimes lead to security problems because it causes the OS to open a file is the "wrong" program if the file extension isn't named right.

Another is to utterly ignore the extension and just read the starting bytes of the file's content. Pretty much all files use an ID code as the first few bytes of content that define the file type. They all do this other than plain old ASCII files (Or Unicode UTF-8 files which end up kind of being the same thing as plain old ASCII.) In the UNIX world the first two bytes of file content were referred to as the file's "Magic Number" and you could figure out the type just from those two bytes. But later the algorithm to identify a file by its first few bytes got more complex as some files started using longer byte patterns so it's not just the first two bytes now sometimes it's the first 4 or the first 8.

In the Windows world, it wasn't so common to use the "magic number" idea originally, but it tends to use it more nowadays than it used to.

The problem with using the "magic number" method is that while it may be much more reliable than using the file extension that any user can just name wrongly, you cannot see this "magic number" until you open the file and start reading it. When the file is just a directory entry in a folder and you haven't looked inside it yet, you don't have anything to go on other than the extension. It's impractical and slow for a program that's showing a list of files in a folder to open every file one at a time to read the magic number from all of them. It relies on the file extension to decide what to show you on the screen for the file's icon, and to guess what program should open the file.

The reason .webp and .jpg both work is because often the same program that can read a .jpg file can also read a .webp file, so once the program is opening the file and reading the content, it (should) no longer care what the filename extension was and just believe the magic ID number in the file's content. When it reads that it goes, "oh, this is webp. Well I know how to display those so I'll read this file as webp and show it" and it completely ignores that the filename claims it's a jpeg file.

The place where the file extension being wrong for the format causes big problems is when the program that can read a file of one type cannot read a file of the other type. Then the extension being wrong causes the system to open it in the wrong program, which can't deal with it.

Generally the difficulty I have in questions like this is that often the answer is couched in Boolean terms which are useless to me.

It's not like its "At 24 hours you were not contagious at all and couldn't spread it to anybody, then at 25 hours all of a sudden you were 100% contagious and will spread it to everyone you ever talk to, then 5 days later you will be 0% contagious again and cannot spread it at all." It begs the question, how contagious do you have to be before a virologist will call you "contagious"? What's the actual cutoff they're using? It's not Boolean so what is it? The answers are often couched in terms as if it was, which frustrates me as a layman.

As someone who was vaxxed but got Covid-19 a couple of weeks ago, I still have a slightly drippy nose making me have to clear my throat of mucous about once an hour or so. All other symptoms but that one only lasted a few days and I feel absolutely fine. I can't tell when it's going to start being okay to visit other people again. The isolation and cancelled plans are frustrating me, and home antigen tests are still positive even though I feel just fine. How contagious am I really? It's probably not completely impossible for me to spread it, but it's probably nowhere near as likely as it was back when I was 4 days into it and was having high fever, headache, and constant snot everywhere.