Tell the truth, what will happen if the sky falls?

No kidding, scientifically speaking, seriously imagine what would happen if the sky fell? What if the earth's atmosphere collapses and all the molecules on our heads fall off?

Paradoxically, this is not a frivolous thing. The total mass of all oxygen, nitrogen and other substances in the earth's atmosphere reaches 5 trillion tons, so the falling sky means that about 10 tons of molecules, which is equivalent to the weight of a school bus, will fall to every square meter of the earth's surface. As a result, everyone will be crushed into pancakes.

To make things more interesting, let's imagine a less destructive scenario: what if the atmosphere suddenly disappears and an extremely rare quantum fluctuation causes all atmospheric particles to jump to the other end of the galaxy unexpectedly, leaving the earth floating in a vacuum?

The sky disappeared.

Vaclav Smil, a professor at the School of Environment of Manitoba University in Canada, said that there are three situations that will kill us: lack of oxygen, sudden drop in temperature, and full-dose ultraviolet rays exposed to solar radiation. At present, most ultraviolet rays are blocked by the atmosphere. Professor Smir said that lack of oxygen is the first priority, and once lack of oxygen, people can't survive.

Professor Smil said that most life will die of lack of oxygen within three minutes. Because there is no air flapping its wings, all birds and insects in the air fall around us like stones. Because there is no air to transmit sound normally, the world is silent.

If someone happens to be a hospitalized patient wearing a ventilator when he disappears for a few days, he is still unlucky. Jeffrey Landis, a scientist and science fiction writer at NASA Glenn Research Center, said that even wearing a respirator or having other sources of oxygen (such as a diving cabin) is not enough. We can't breathe without atmospheric pressure. Because the air inhaled and exhaled by the lungs needs to be distinguished from the external air pressure by raising and lowering the internal air pressure of the human body. If there is no difference in air pressure between inside and outside, people can't breathe.

After our demise, the earth will gradually get cold. The atmosphere usually absorbs solar radiation to the surface of the earth, thus preventing the heat reaching the earth from radiating into space again to keep the earth warm. Professor Smil said that without this greenhouse effect, the average temperature of the earth would drop to MINUS 18 degrees Celsius, and the temperature difference between day and night would be great.

As for the oceans, they will boil first, and then the top will freeze. Landis wrote that the ocean will boil because when the atmospheric pressure decreases, the boiling point of water will decrease, so soon the earth will have a new atmosphere composed of water vapor. He said that without enough atmospheric pressure, people can't survive without pressure suits. When this pressure reaches only about 2% of the original atmospheric pressure, boiling will stop.

Living in a bubble

Without the atmosphere, can anything on the earth survive? Dr Lynn Rothschild, an evolutionary biologist and astrobiologist at NASA's Experimental Research Center, said that there was no life big enough to be seen at that time. Complex organisms are aerobic, but anaerobic organisms, such as some bacteria, can survive, but only species living underground can survive. The problem is that if there were no ozone layer, there would be a very high amount of radiation on the surface of the earth, and under this high radiation, the surface would immediately become barren. However, tens of centimeters below the ground, there will be a prosperous (though invisible) ecosystem.

If we know in advance that the sky will disappear, there are two ways to prepare for this change. First of all, we can build a sealed and pressurized dome and plant various plants, which can not only maintain the carbon and oxygen cycle, but also serve as a food source. Just like living on a planet or the moon without air, we need a stressful habitat. Landis said that there are many plans to make the lunar base self-sufficient, so if we have time, we can turn it into a habitat.

The second method gets rid of the need of artificial pressurization, and we can live underwater. As long as it is 10 meter deep, the water pressure is equal to the atmospheric pressure on the earth's surface. Therefore, as long as we can find a way to make oxygen breathe (perhaps electrolytic seawater), we can live underwater.