I’ve seen this Buzzfeed video floating around a bit on the internet (a more readable picture version is here). Purportedly, it explains what would happen if the Earth lost oxygen for five seconds. But… well, perhaps you shouldn’t use Buzzfeed as your main source of scientific information.
So, what would really happen?
1) A few million years from now, alien astronomers would get very excited
The Buzzfeed video doesn’t just talk about “What would happen if molecular oxygen disappeared”, they ask what would happen if every single oxygen atom disappeared – even atoms in compounds.
The Earth contains around 1050 oxygen atoms. In normal notation, that’s 100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 atoms. Each one only weighs a tiny, tiny amount, but when you have 1050 of them together, it adds up. The total weight of oxygen on Earth is around 2 thousand billion billion tonnes, and as we know from Einstein, E (energy) equals m (mass) times c (the speed of light) squared. The speed of light squared is also a gigantic number, and multiplying one gigantic number by another gives an even more gigantic number. The energy released by the sudden disappearance of oxygen would be:
1.841 joules (which, for scale, is 40 billion billion billion billion food calories)
This energy, in the form of heat, would very quickly pass into the remaining particles that make up the Earth. For a split second, perhaps, you would see some interesting chemical reactions occur, before the electrons become stripped from their atoms, and then the atoms themselves break down into protons and neutrons, and then finally those protons and neutrons would boil away, leaving just quarks, the fundamental particles of matter, floating around in a very hot soup known as a quark-gluon plasma.
The formation of a quark-gluon plasma would release even more energy – in protons and neutrons, almost of the energy what’s known as “binding energy” (around 95% by my calculation), which is the energy used to hold the particles together. When they disintegrate, this binding energy is released. In effect, this would push it up another 3 or 4 times.
1.841 joules is a lot of energy, of course, but on universal scales, we’ve seen better. Supernovas, the explosive death-throes of stars, can release a hundred thousand times as much energy as that. While we don’t know how quickly all the oxygen vanished, Buzzfeed gives us an upper limit of five seconds. This corresponds to 10 thousand billion billion billion billion watts, which effectively makes the destruction of the planet a decent sized gamma ray burst, taking nearby planets (and any life on nearby worlds) with it.
2) The air would freeze
Ok, let’s assume, somehow, the planet didn’t explode. Maybe the oxygen suddenly fell into a parallel universe without releasing any energy.
One of Buzzfeed’s other claims is that the seas would evaporate as H2O became pure old H2. What they don’t mention though is that in water, the oxygen is in the middle. The hydrogen molecules are not connected to each other. Delete the oxygen, and you have hydrogen atoms floating around freely. Hydrogen doesn’t like being an atom, though, and it would almost instantly react with other chemicals – mostly, other hydrogen atoms. Forming the bonds between the hydrogen atoms would require energy (like the binding energy already mentioned), which the hydrogen would steal from its surroundings in the form of heat.
The seas contain a lot of hydrogen (there’s even more if we include vapour in the atmosphere) – about 60 billion billion billion billion billion atoms. To turn all of this into hydrogen gas would take 10 billion billion billion joules of heat energy – this is more heat energy than the entire atmosphere. While this endothermic reaction happened, the temperature of the planet would plunge to almost absolute zero.
3) Your ears would not explode
Ok, ok, let’s assume the planet neither boiled into subatomic plasma nor froze. Would your ears burst, like Buzzfeed claims?
Air pressure is mostly a function of the mass of air pushing down on you. Taking the oxygen out of the air would reduce the atmosphere’s mass by about 20%, so sure enough, air pressure would also decrease by about 20% (as far as I can tell, the number of particles in the air doesn’t matter so much. Particles move very very quickly to spread themselves out equally, and it would take way less than 5 seconds for them to spread out to equalize the pressure).
But 80% of atmospheric pressure is still a lot of pressure. When you fly, that’s about the air pressure in the plane cabin. It would hurt for the air pressure to drop that much, but it would be unlikely to make them burst.
What about if oxygen doubled?
Would we really be happier and more active? In fact, the body can’t really use excess oxygen. Already, a lot of the oxygen we breathe in comes out unabsorbed. Breathing in extra oxygen is unlikely to have any effect on the body.