"My fictional scenario has to do with space. Or generally, when you take oxygen out of a room. What will happen to the person? How long will it take for them to realise they can't breathe? What symptoms come first and how long before they kaputz... And out of curiosity, why oxygen? What's so special about oxygen that we need? Why not any other types..."
Oxygen. How I love thee, let my brain count the ways...
See this formula?
C6H12O6 + 6 O2 + 38 ADP + 38 phosphate → 6 CO2 + 6 H2O + 38 ATP
In non-chemistry speak, that means "sugar + oxygen = energy."
This is one of the many equations for why we're alive. Without oxygen and glucose, you can't live.
And out of curiosity, why oxygen? Why not nitrogen, or helium? (See the Botanist's great comment below--well said!) Without getting all Carl Sagan-ish on you, basically, that's how life on earth simply is. Life is based on carbon building blocks (like sugar, and protein, etc) and oxygen as the means to make it run. Perhaps on another planets or systems, things could evolve to run on other elements? I'm sure a chemist would laugh at me for saying that, but it's fun to imagine.
When you take oxygen out of a room, what will happen to the person?
So your body needs oxygen, particularly your brain. When it doesn't get enough blood supply (meaning the delivery of oxygen), it stops working = you pass out. In an oxygen-less environment, that might take a minute, more or less.
What Fiona's question is dancing around, though, is what about if you were in a vacuum? Like in outer space? That doesn't mean a room without oxygen, or even a room with a Hoover. It means a room without ANYTHING, including pressure and air.
If a person took a foolish, naked step off the Space Shuttle, they'd encounter the following:
- no oxygen
- no pressure
- extremely low temperatures
Living on earth means we are in a tightly pressurized cocoon of oxygen and other gases, courtesy of our atmosphere, which sticks to the earth because of gravity. At or above the Armstrong limit, around 62,000 feet above the earth's surface, the lack of pressure will cause oxygen dissolved in human blood to form bubbles. Yeah, that's boiling blood.
Now, at 62,000 feet, your body's tissues and skin are tough enough to keep up the pressure within the body so you don't explode, but you will start to have serious symptoms of altitude sickness, caused by these forming bubbles in the blood and tissues. Also, if it's a sudden exposure, the symptoms are worse.
- Without a spacesuit and with full body exposure to space's vacuum, you'd last maybe with 15 seconds of consciousness.
- If they could get you back on the shuttle immediately, into a re-compression chamber and with intensive medical care, you might survive.
- Before you passed out, you'd notice your saliva boiling off your tongue (this is not "hot," temperature wise--it would be the sensation of liquid quickly bubbling and vaporizing away), fluid/blood frothing in your lungs, mouth and eyes, and maybe the extreme cold temperature (well below zero).
- Soon, your heart would stop (asystole, or "flat lined" at the 2 minute mark, or probably earlier--see my comment about the Soyuz 11 disaster in the the comments section), and the entire time, gas bubbles would expand in your body. Blood vessels would pop through your skin as your blood vaporized into space. Some of it would coagulate on your skin or air passageways. Your lungs would suffer from popped air passages filling with boiling and/or coagulating blood.
- At the five minute mark, your heart and brain are permanently damaged and frying away. And yes, at this point, you're probably very dead.
A fascinating, if not ewwww-ish topic for today. Thanks Fiona!
There were a few references I used to research this topic.
Can you survive space without a spacesuit? This is a good one. In the sci-fi movie Sunshine, a guy takes a spacewalk with a suit and survives. This article explains how it might have made sense.
Ebullism at 1 million feet: The human struggle with altitude. There are examples of people surviving explosive decompression above the Armstrong limit. I did not make up the boiling saliva comment, it's from this reference.