We require oxygen to live. So would an atmosphere composed of 100% oxygen be good thing?
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00:00 Imagine striking a match
00:02 and having everything around you catch on fire.
00:05 Even if you were standing in a wet forest.
00:08 And while that's happening,
00:10 imagine being chased by giant insects.
00:13 These are just a few of the things that would happen
00:16 if you lived in a world
00:17 where the atmosphere was pure oxygen.
00:21 What other things would happen on Earth?
00:24 Would you be able to survive this?
00:27 This is WHAT IF,
00:29 and here's what would happen
00:30 if Earth's atmosphere was pure oxygen.
00:34 Oxygen takes up just over 20% of our atmosphere.
00:38 The rest is mainly nitrogen.
00:40 It's no secret that you need oxygen.
00:43 It allows us to breathe,
00:44 and it's responsible for all forms of life.
00:47 If there were no oxygen in the atmosphere,
00:49 everything would die, including you.
00:53 But what would happen
00:55 if the atmosphere was nothing but oxygen?
00:59 At first, it may sound like a good thing.
01:01 Oxygen is what helps us live
01:03 and gives our bodies energy.
01:05 More of it has to be a good thing, right?
01:07 There are even oxygen bars all around the world
01:10 that offer hits of 95% oxygen.
01:13 These services claim a number of things,
01:15 from making you more productive at work,
01:18 to being able to cure your hangover.
01:21 If you were able to breathe 100% oxygen all the time,
01:25 would it make you an extremely energetic,
01:27 superhuman version of yourself?
01:29 Nope, not at all.
01:32 "Hey!"
01:34 Too much oxygen is actually a bad thing.
01:37 At a certain point,
01:38 it can be downright poisonous for humans.
01:41 If you breathe in too much oxygen too fast,
01:44 it creates free radicals.
01:46 Free radicals are unstable atoms
01:48 that damage cells,
01:49 and they're linked to a variety of diseases,
01:52 including cancer and Alzheimer's.
01:55 They're also thought to be linked to things like
01:57 wrinkles and gray hair.
01:58 So if we were able to survive an extended period of time
02:02 with pure oxygen in the atmosphere,
02:04 we'd most likely appear much older.
02:06 But that could only happen if we evolved
02:09 and adapted to live in an oxygen-only atmosphere.
02:13 If it happened instantly,
02:14 your chest would be hurting each time you took a deep breath.
02:17 Fluid would accumulate in your lungs,
02:19 and you'd start to become dizzy and lightheaded.
02:22 As you kept breathing,
02:23 your lungs would begin to get damaged,
02:25 and so would your brain,
02:27 until you lost consciousness and died.
02:30 For insects, it might be a different story.
02:33 Around 300 million years ago,
02:35 giant insects roamed the Earth.
02:37 At that time,
02:38 the Earth's atmosphere was 35% oxygen,
02:41 a lot more than the 20% we breathe today.
02:44 Researchers suspect that the increased oxygen
02:47 was responsible for those giant insects.
02:50 It had to do with the tracheal system,
02:52 a network of tubes that brings oxygen to the insect's cells
02:55 and takes away carbon dioxide.
02:57 If there was more oxygen in the atmosphere,
02:59 the insects' tracheas would expand,
03:02 and their bodies would get bigger.
03:04 But what about those crazy fires we mentioned before?
03:08 Well, if you happened to survive long enough to light a match,
03:11 you wouldn't last too long after that.
03:13 As soon as you brought your flame to something, anything,
03:16 it would instantly catch fire in a massive explosion.
03:20 You see, oxygen is a key ingredient
03:22 to what makes a fire spread and expand.
03:25 If we only had oxygen in our atmosphere,
03:27 our fires would become massive.
03:30 What was once a small campfire
03:32 would now be a fiery explosion.
03:35 So even if you could breathe in an atmosphere of pure oxygen,
03:39 the giant insects and the Earth burning all around you
03:42 would make life pretty tough, even impossible.
03:45 The only way to survive would be to adapt,
03:47 and to make sure fires never happened.
03:50 What would your life be like without fire?
03:53 Well, that's a story for another WHAT IF.
03:57 (upbeat music)
04:00 (upbeat music)