If you were aboard the falling ship, you wouldn't notice anything unusual, though, because all the processes you'd use to observe clocks would also be slowed down. Time dilation is always something you observe in others, not yourself.

let's imagine you're hanging out near a black hole (but not in it).

one thing to keep in mind, you would not notice time slowing down. your time as far as you're concerned would feel exactly like it is now. you'd look at your watch and it would tick at the same rate. you'd still be breathing, your heart pumping as normal. you'd hold normal conversations with the people next to you.

but, me, hanging out over here on earth, i could watch you through a telescope. and I'd see you moving in slow motion. your watch would tick more slowly than mine. your conversations would be lower in pitch and take longer. if you looked at me through a telescope, I'd be sped up. my watch would tick faster, my voice would be sped up like a cartoon character.

the closer you get to the event horizon the more extreme this effect. the most likely impact of this would be communications. in reality I'd never have a telescope that could view you. but you could flash a really bright light towards me, and communicate in morse code (or more likely a digital computer protocol). I'd see your flashes going very slowly. if i knew how fast you were flashing your light from your perspective, i could tell exactly how close to the horizon you were. weirdly, your light would get more and more red as well, for the same reason your voice would seem lower to me.

conversely, if i flashed a light at you, you'd see it flashing faster and more blue.

this effect is actually seen in our gps satellites. time goes slightly different for them (i think faster, as they're not in our gravity well, but there's other aspects that affect this too, like speed). so we need to account for the different clocks for gps to be accurate.

Yes that and they see the light emanating from you and your clock become ever more ‘red shifted’.

> It means as an outside observer watches you fall, they see each tick on your clock taking longer and longer to happen the closer and closer you get to this magical point

I sort of worked this out from watching my dogs hair grow back. Either it falls out at a certain length (and regrows) or just stops growing.

[removed]

Both of those are blood vessels. The definition is that an artery carries blood away from the heart (to other organs), and a vein carries blood to the heart (from other organs). This definition is chosen because the walls of an artery need to be thicker than the walls in a vein, because of the pressure from the heart pumping blood.

Most arteries are carrying blood with oxygen and most veins are carrying blood without oxygen, but the opposite is true for the arteries and veins going to and from the lungs (the pulmonary arteries/veins) - those arteries carry blood without oxygen and the veins carry blood with oxygen.

It means as an outside observer watches you fall, they see each tick on your clock taking longer and longer to happen the closer and closer you get to this magical point

A shaman in tribal societies of Northern Eurasia is a person who can communicate with the spirit world in order to make the spirits help people in desired ways: healing, fortune telling, enchanting amulets etc. A shaman is supposed to enter an altered consciousness state to do this. For that they can take certain mushrooms or other substances, meditate, make hypnotizing music and dances and so on. In short, a shaman in a shamanistic belief system is like a priest in a religious system.

[removed]

The event horizon is the edge of a black hole.

Black holes exert gravity.

The move gravity in an area the slower time travels.

Technically this means if you could chill out next to a black hole for a few days you could come back to earth but it will be years ahead here.

The more gravity you are experiencing, the more that time slows down for you. Black holes have a lot of gravity so time would slow down a lot if you went near one.

No. Over-saturation of O2, i.e. hyperoxia, certainly isn't healthy but the symptoms aren't as acute, and the partial pressure of oxygen in normal air simply isn't high enough to cause oxygen toxicity (at sea level pO2 is about 21 kPa and toxicity only occurs above 30 kPa). That is, no matter how fast you breathe, in normal air you can never raise your blood oxygen to toxic levels.

People panicking breathe too fast, and breathe out more co2 than your body is used to. This makes you feel weird (light-headedness, fingers tingling, that sort of thing).

The idea is that re breathing the air you just breathed out should slow the co2 loss and make you feel better. My understanding of why we stopped doing it is its just a lot more effective to get the person to slow their breathing by talking them through it, and the paper bag thing never practically worked that well (while the theory is sound, in practice you have to strike a reasonably fine balance in having a rebreathing circuit open enough to allow plenty of oxygen in but still retain co2, and that's just really tricky).

People sometimes breathe much faster than is healthy. This is called hyperventilation and can be caused e.g. by anxiety or stress. When you hyperventilate, you're saturating your blood with oxygen, and depleting it of carbon dioxide (CO2). CO2 dissolved in liquid (such as blood) makes an acid called carbonic acid. Without CO2 in your blood, you're missing this acid and your blood becomes more alkaline, which causes a syndrome called hypocapnia, which is associated with symptoms such as dizziness, fainting and (more) anxiety.

So, to sum up: people who are hyperventilating run a risk of having too little CO2 in their blood. The idea behind breathing into a paper bag is that you would breathe out air with more CO2 in it (compared to regular air), and then by breathing this back in you would raise your CO2 levels.

There are two reasons why this method is no longer recommended: (1) it's rather ineffective and (2) it can be very dangerous:

1. Experiments have shown that CO2-levels barely increase faster by rebreathing exhaled air, and no more than a placebo condition where people believed they were rebreathing, but were in fact breathing normal air. Why does a placebo method affect CO2 blood levels? Well, because simply relaxing and breathing more slowly is an effective method of raising CO2, and a placebo treatment can help reassure people that they will be okay. They believe that it will help, and that makes them relax.
2. Symptoms resembling those of hyperventilation can be caused by conditions such as asthma attacks or heart attacks. And sometimes people who hyperventilate do so because they are actually low on oxygen (due to some other medical reason). In all these cases, making people breathe into a paper bag can be very dangerous, and even lethal, as you are depriving them of much-needed oxygen.

So the takeaway is that at a minimum, you should exercise an abundance of caution when attempting the paper bag method. Never have someone else hold the bag for you (let alone hold a bag over another person's mouth if you think they are hyperventilating). Never use this method if you suffer from any kind of heart or lung problems, or if you've ever head a stroke, embolism, blood clots, etc. Only breathe into the bag for a few breaths (most sources recommend no more than 6-12 breaths). And avoid using this method if you're not sure that you're hyperventilating.

[removed]

Putting this here since it’s not allowed to be a top-level comment, but I found this YouTube video to also be helpful in explaining these common US medical insurance terms. The system definitely presented as something that should be changed, but I found the information given as helpful.

https://youtu.be/-wpHszfnJns

IT is NOT the over saturation of O2. Theres a relative plateau you reach as you hyperventilate in terms of how much O2 you can accumulate (and its pretty close to what you live at normally) but your body is able to blow off a tremendous amount of CO2, which is an acidic compound. As you blow it off your blood becomes more alkaline, which causes some temporary problems-- dizziness, weakness, more anxiety, and carpopedal spasms. If you ever see someone in a BAD panic attack they will sometimes feel cramping in the feet and hands, or even contract the muscles in their feet and hands. It tends to make them panic more and slowing down their breathing is pretty much the only way to turn it around.

Divers actually take advantage of this sometimes, they hyperventilate before a dive to suppress their respiratory drive by blowing off CO2, but it can be kind of a risky technique because your oxygen level doesnt really rise that much.

O2 toxicity tends to only happen with overdelivery of oxygen, on room air its pretty difficult to accomplish.

Your body only knows to breathe because of increasing CO2 concentration, so unless you tape the bag to your face, you are likely to know when the air in the bag is too stale. Too much or too little O2 isn't something you can detect.

That is also why hyperventilating and holding your breath can cause you to fall unconscious, you run out of oxygen without hitting CO2 levels which tell your body to breathe. Never try to hyperventilate in order to hold your breath longer, doubly so if it's to dive underwater.

Why does the blood alkalinity matter? Isn’t it just the over saturation of O2 that causes issues?

Depending on the place, its about style and beard quality also

Hair is not circular in cross section, unless it's perfectly straight. Hair with oval or orregular cross section will be various forms of wavy, curly or tight curls.

As for why pubes are so curly, it's theoretically hygienic/ protection for the public region against certain things (but then promotes other things like crabs, so win some lose some on an evolutionary balance)

Fair point i’ll have to do some googling then

Fair point i’ll have to do some googling then

Yknow, the US is best friends with Saudi Arabia.

And were And is avoiding Chinese technology even though it'd help them, as a move against China

Yeah, Pooh Bear totally supports the people’s right to speak their mind. lol