What would happen if the earth lost its atmosphere? (QOTD #4)

Probably not anything good.

By Muhan Sun

It’s a lovely afternoon, the sun is shining, birds fly twittering over the trees. The next instant, everything is plunged into darkness. The world falls silent and your lungs start feeling tight. The last thing you see before you blackout, are the birds dropping from the sky.

Effects of Losing the Atmosphere

What we’ve described here is what you can expect to experience if the earth ever lost its atmosphere. Of course, your survival will be too brief enough to witness most of the dramatic changes, but it will be long enough to notice some differences. Due to the loss of atmosphere and the ensuing vacuum, all sound disappears, as sound waves cannot travel without a medium. The sky turns pitch black, much like the pictures we see taken from the surface of the moon, for example. The lack of air also causes birds and planes to fall out of the sky because they require the mass of air to fly. Of course, the air is also vital for human life, so this is probably also the stage where you would perish. But let’s pretend that we were alive to witness the rest of the aftereffects.

All bodies of water on the earth would start to boil, due to the fact that the boiling point of liquids is reduced as the external pressure is reduced. Eventually, the water would stop evaporating and the rest would freeze. The temperature on earth would be extremely low by our standards, at around -18 degrees celsius.

If we take a look at the distant future and how the earth would progress, we stumble across some interesting discoveries. A new atmosphere would eventually form, made up of gases pumped out by geothermal vents and volcanoes, as well as oxygen created by the solar radiation breaking down water vapour. This atmosphere would be too thin to breathe in, however.

Could this happen and how do we survive?

The short answer is no. As long as nothing drastic happens, the molecules in the atmosphere remain bound to the earth. The earth, unlike Mars, for example, is large enough that the gravitational attraction prevents almost all the molecules from escaping. As of now, the only foreseeable possibilities of the earth losing its atmosphere are massive solar storms (which would burn away our atmosphere) or a collision with a large meteorite.

Hypothetically, if such an event were to occur, we would probably have to resort to living in radiation-shielded domes (similar to the domes present in sci-fi movies when colonizing other planets), due to the fact that we no longer have an atmosphere shielding us from solar radiation. These would have to be pressurized, as well as support plant-life, in order to provide us with a source of oxygen and nutrition. Movement outside of the domes would only be possible with pressured, anti-radiation suits and oxygen tanks.

While this might all sound frightening, the chances of our atmosphere disappearing are so minuscule that there is no point worrying about it. We may as well enjoy our sunny afternoon without this on the back of our minds.