They don’t build the second floor perpendicular to the first floor walls, they independently make sure each floor is level and each wall is plumb.

The other reason the bag method isn't favored anymore is that people have had the idea that any bag will do and suffocated themselves with plastic.

Quieter, cooler, better air quality, better mental health, more birds and bugs, I'm sure there are more.

Apart from other answers it also really helps with protecting the biodiversity that cities slaughters. So birds, insects and whatnot can have someplace to live in between all the concrete.

As another comment correctly pointed out, hyperventilation lowers your blood CO2 levels below normal/healthy thresholds, and the intent of paper bag rebreathing is to slow your breathing, and have you breathe in less oxygen-rich air/previously exhaled CO2. While the mechanism of:

>hyperventilation -> low blood CO2 -> increase blood CO2 -> alleviate hyperventilation

is well accepted, I don't believe that there is robust science supporting paper bag rebreathing specifically.

Additionally, paper bag rebreathing can kill people who are sensitive to hypoxia (lack of/low oxygen) and people who are suffering medical emergencies that appear like anxiety attacks but aren't (commonly heat attacks). AFAIK, the current recommendation is to coach people through their breathing, and to have them breath through pursed lips. While paper bag rebreathing should be fine for otherwise healthy people, there's not really a reason to use a method that could be dangerous when there are less/non-dangerous methods available.

IMPORTANT

BREATHING INTO A PAPER BAG IS ONLY USEFUL FOR CERTAIN CAUSES OF HYPERVENTILATION—FOR OTHERS, IT CAN MAKE THE SITUATION WORSE!

basically, carbon dioxide as a waste product that, when dissolved in the blood, makes it more acidic. when someone is blowing off too much carbon dioxide but is otherwise physically healthy, for example during to an anxiety attack, breathing into a paper bag helps to recoup some of that carbon dioxide, thereby keeping their blood from getting too basic. this important because everything in our body works best within a really very narrow pH range, as all of our body’s functions are optimised for that range and may work poorly or even not at all out of it.

IF, however, a person is hyperventilating as compensation for their blood being too acidic, such as with kidney problems or certain toxic substances, breathing into a paper bag is a HUGE mistake, as it interferes with the lungs trying to fix the acidity as best as they can!

another reason for hyperventilation is low oxygen levels in blood, even when CO2 may be normal or high. this can be do to a very wide range of things—there’s no one sign that’s guaranteed to always be there—but you may notice they are blue or grayish around the edges, especially around the lips and nails. it goes without saying that these people also should not be made to rebreathe from a paper bag, since they’re gasping for more oxygen, not trying to blow off more carbon dioxide.

that’s why it’s really very important to have a good idea of why someone is hyperventilating before trying to treat it. even in case of anxiety attacks, unless they’re common and the person having them is aware of what’s going on, rather than giving them a paper bag, it’s better to have them: sit or lay down, ideally with the head level with the heart and help them through breathing/mindfulness exercises. sometimes one kind of hyperventilation masks itself as another, so without the ability to check blood tests, better safe than sorry 💕

I just by halal bovine gelatin off Amazon in one kilo pails for $25. Same amino acid profile. Ridiculously cheaper than the fancy degraded collagen, which is exactly what gelatin is.

TLDR: boats

Suspension bridges at a basic level only required a rope to be pulled across a river, and that can easily be done with a boat.

Larger footings could be poured from a boat as well.

While there's a lot of prep work and drilling down on a river bed for bridges today, it more ancient times they would likely have just floated a barge to the spot and dumped large quantities of gravel and large rocks to create a solid footing

Parks raise the economic value the neighborhood. Both homeowners and businesses like to be near a thriving park. Fees for recreational activities and an increased tax base easily cover the costs of building and maintaining parks. Even in very urban areas, developers can often be persuaded to build parks in return for permits, and it's a win-win, since the park improves the value of the development.

Parks improve water and air quality, protect groundwater, and prevent flooding. They provide buffers to development. They provide a place for recreation and exercise and reconnecting with nature for children and adults alike -- and often for pets, too. Organized adult-supervised activities at parks keep children and teens out of trouble, reducing juvenile delinquency and crime.

They drained the water.

For building across a river you could wait until a dry season to build your bridge when the water level would be low or you could sink logs into the ground to make a sort of dam around your construction site which you could then drain(either using pumps or just buckets depending on technology) then you build your support pillar before breaking down the dam you built.

Mostly, it involved building in the safest and easiest place instead of the most convenient for travel.

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1. Better mental health. People tend to feel better when they can connect a little bit in and with nature.

2. Better physical health.

3. Helps reduce the urban heat island effect. Turns out concrete and asphalt and all that is really good at putting out heat during the day which means a city will be hotter than the grassy hills outside the city only because of development. Parks can help bring that down a little bit.

4. Can help with water management.

This is probably the best explanation so far. There's a few posts talking about cpus and how many bits they are, but the question was about storage, and this reply describes how a computer (program) figures out what's inside a file.

The rotation can sometimes be surprisingly chaotic, though. Saturn's moon Hyperion wobbles so wildly that it was impossible to plan for a probe flyby to cover unexplored areas.

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“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.”

― Douglas Adams, The Hitchhiker's Guide to the Galaxy

Scale is really hard for our meat brains to understand. Here's a fun video that can help a bit to understand, via a medium of printer paper standards.https://www.youtube.com/watch?v=pUF5esTscZI

You need to know the type of data you are dealing with. For example, if you want to open a .wav file, you find the specification (https://ccrma.stanford.edu/courses/422-winter-2014/projects/WaveFormat/) and then you write your program to the specification.

It says first 4 bytes are the ID, then next 4 bytes are the size, then next 4 are the format... etc. etc. etc.

If somebody just hands you a blob of data and tells you to interpret it, then you are correct to be confused. You'd have no idea what the bytes mean.

Also, if you open a file in the wrong program, it interprets the bytes in the wrong way and you just get nonsense. Open a .exe file in notepad and it's just crazy characters all over the screen.

For the planets, absolutely. The Voyager probes actually relied on planetary flybys to get a "gravity assist" to slingshot them out of the solar system. Lots of calculations involved to make that happen right.

Beyond that though, colliding with a random comet or asteroid is a) insanely improbable and b) impossible to account for if you don't know about them in the first place.

As for a running into another star system, it will take about 40,000 years for either Voyager probe to come within a couple light years of another star (but we do know which those will be)

> OP's question also brings to mind the story of the Curiosity rover on mars.

> It's original tenure was only supposed to be a 90 day mission on the surface, but through a combination of good construction and non-catastrophic conditions, it instead served for 14 years. It didn't stop until a harsh dust storm knocked out its ability to recharge.

You're referring to Opportunity, not Curiosity. Curiosity was activated under 11 years ago, is still operational, and doesn't recharge because it uses an RTG.

Opportunity was deployed for 14 years and relied on solar power.

It's not impossible, however it would be like dropping 8 beach balls and a few dozen tennis balls in random parts of the pacific ocean, and then plotting a random course across the pacific ocean without hitting any of those balls. Sure it's POSSIBLE you could hit one of those balls, but given the vast size of the ocean and the comparatively tiny size of the balls, the chances are pretty darn close to zero.

Only instead of like that, about a million times less likely.

Their orbits are planned out before the mission to begin with. If they weren't no mission would be possible.

The orbits of the planets in our system are well studied, so we know their shape around the sun and the speed the planets have along each part of their orbit, so modelling their orbits into the future is relatively simple. If you've ever wondered how we know before hand when conjuctions will happen or when a comet will pass by or how astrological predictions are made for future dates, that's how. (Astrology isn't a real science but it relies on our good understanding of our solar system).

We also know their mass and their gravitational force, so complex calculations are made that can chart a spacecraft's exact course through space which also determines how much fuel the spacecraft itself needs for maneuvers and how much of its course will rely on the gravitational pull of other celestial bodies. Space is mostly empty, and vast, so the chances of a random piece of debris or asteroid hitting the spacecraft are not zero but they're highly impropable.

Nowadays these calculations are carried out by complex computer modelling but it's not a simple calculation that one can simply write out here. But what you can do is get Universe Sandbox, which is a game that models our solar system fairly well and allows you to change variables or simulate missions which helps visualise and give a much more intuitive understanding of how these things work. In fact there's a whole host of such software but this one I think is a great one for people interested in learning about our solar system, space and how missions work

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Planets are hard to miss and they do not take unexpected turns like some drunk git on a highway. If you know where Mars is now and its velocity, you can predict where it'll be in exactly a thousand years, probably down to a few tens of meters of accuracy.

In space unless you aimed REALLY well you aren't hitting anything. No matter how empty you think it is it's a billion times emptier.

They didn't do any crazy math to make sure they weren't going to hit anything. They did crazy math to make sure they got within very precise distances of each planet they visited to get a gravity assist. Each gravity assist sped up the probe until Voyager 1 was going about 17km/s and Voyager 2 was going about 15.5km/s. No rocket is capable of getting them to those crazy speeds.

After they each finished visiting planets they were on their way out of the solar system. There just isn't any risk of them crashing into anything.