2023-10-02 19:00:00
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Seventy-two meters is not even the length of a professional football field, but it is the exact number that Italian freediver Umberto Pelizzari swam unassisted to in 1992.
This is what scientific popularizer Bill Bryson says in his book A short history of almost everythingin which he explains that human beings Not only can we not breathe underwater —1,300 times heavier than air—but also our body is not conditioned to withstand the pressure.
Every 10 meters of depth, the pressure increases by one atmosphere. At the average ocean depth, that is, 4 kilometers deep, the pressure would be equivalent to the weight of 14 trucks loaded with cement placed one on top of the other. In the Mariana Trench, the deepest point in the ocean, the depth reaches 11 kilometers.
Challenge in the abyss: James Cameron’s descent to the deepest point of the ocean
And, as Bryson says, “from the deepest ocean trench to the summit of the highest mountain, The zone that includes all known life is only about 20 kilometers thick.”. Much of the planet is too hot, or cold, or dry, or high for human adaptability: “As much as 99.5% of the volume of the world’s habitable space is, by one estimate, in practical terms, completely out of reach.” our limits.”
In the heat of the desert, on foot and without water, most people would become delirious and faint. In the cold, although humans are mammals, because of their little hair we cannot retain too much heat; That is why, even with a mild climate, half of the calories we consume are used to keep the body warm. So, even if we have enough water, clothing, shelter, the parts of the Earth in which we can live represent “only 12% of the total land area and 4% of the entire surface if we include the seas,” says the author of the book. .
The truth is that, if you consider the conditions existing on neighboring planets – and in the rest of the known universe – what is surprising, Bryson said, is not that we use so little of our planet but that we have managed to find one in which we can use something. Most places in our own solar system are significantly more inhospitable and less conducive to supporting life. How “lucky,” then, have we been to live on this habitable planet?
The Venus case
On the one hand, we are, “to an almost supernatural degree,” at the exact distance from the exact type of star so that it radiates enough energy, but without it being so large that it is consumed immediately. According to estimates, If Earth had been just 15% further from the Sun or 5% closer, it would have been uninhabitable.
A case that exemplifies this is Venus, where solar heat arrives only two minutes earlier than on Earth, but This subtle difference means that our planet has been able to conserve water on its surface and Venus cannot.. Scientists believe that Venusian hydrogen atoms escaped into space when the water was consumed and oxygen atoms combined with carbon, creating a gaseous greenhouse carbon dioxide atmosphere. Its surface temperature is around 470ºC and its atmospheric pressure is 90 times greater than Earth’s.
Instead, Earth’s magma created gas outpourings that helped form an atmosphere and the magnetic field that protects us from cosmic radiation. Tectonic plates shake and renew the surface: if the Earth were completely smooth, it would be completely covered in water.
In addition, On the globe there are the necessary elements to keep us alive, such as oxygen, carbon and hydrogen; We need iron to make hemoglobin, cobalt to form vitamin B12, potassium and sodium for nerves, molybdenum, manganese and vanadium for enzymes, among others.
Furthermore, without the stabilizing influence of the Moonour planet “would wobble like a top when it lost momentum,” since this makes the Earth rotate at the right speed and at the right angle.
Molecules essential for life are detected on Saturn’s moon
In short, unlike the neighboring stars, Our planet has four main “advantages”: its location, its elements and proportions, the existence of the Moon and excellent timing. To use Bryson’s words, “if a long, inconceivably complex series of events, stretching back some 4.4 billion years, had not occurred in a certain way and at certain times,” we would not be here.
If you have been interested in this topic, you can find more information in the book “A short history of almost everything”published by RBA, in which science communicator Bill Bryson explains the foundation of the solar system, the history of the atom, cells and even the story of how the last dodo bird disappeared.
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