Why did you always get your age wrong, according to astrophysicists | Cosmic Void

How old are you? This is a simple question that we’ve all been asked at one time or another. But the answer is not so simple; In fact, it’s amazing if we stop to think about where we come from. The main thing is to realize that the elements that make up our body are older than we think, even older than our planet.

Here’s the explanation: It’s often said that we are stardust; very nice, I’ve already heard a lot, but this is not entirely true. If we ask ourselves how old our body is, we must analyze what the human body actually is. Well, our bodies are mostly made up of water (about 60% by weight). That’s H₂O, two hydrogen atoms for every oxygen atom, meaning that most of the roughly 7,000 quadrillion atoms that make up us are hydrogen, about 62% by number. And how old are these hydrogen atoms? The answer is again not simple. Hydrogen atoms consist of one proton and one electron. Well, protons appeared in the Universe, according to our latest calculations, a little less than 13.813 million years ago, with an error of 38 million years up or down.

In particular, the protons of almost all hydrogen atoms existing today appeared from the first second after the Big Bang and in the first 3 minutes, counted from this moment 13.813 million years ago. From the first second of the existence of our Universe, the quarks that previously dominated the entire cosmos disappeared, forming protons and neutrons. Also, at that distant time (but it happened here in the neighborhood, in the same place where you are reading this article – and anywhere -) electrons were already quite oldformed between one millionth and one billionth of a second after the Big Bang.

But electrons and protons did not combine to form hydrogen until 380,000 years after the Big Bang. So, 62% of the atoms in my and your body (which make up 8% of its mass) have a colossal more than 3 times the age of formation of our planet, that is, the moment at which the ball on which we live was created. And this makes us say that we are not such stardust as is often said; Rather, our atoms were, for the most part, conceived shortly after the Big Bang.

Returning to our composition in terms of molecules and their atoms, we left the oxygen hanging. Moreover, this element is very important because although hydrogen is the most abundant atom in our body, if you look at mass, oxygen predominates, which is about 16 times heavier than those protons and electrons we talked about. 65% of our mass is oxygen.

And how old is that oxygen that dominates what we see on the scale? There are astrophysicists who have been asking this question for decades and looking for oxygen, which is actually easy to find in the Universe, in increasingly distant galaxies. Oxygen was noticed when the age of the universe was less than 3% of its current age. Seeing distant galaxies means looking back in time because they are so far away that light takes almost an eternity to reach us. And this delay allows us travel in space-time. Our research tells us that three-quarters of the oxygen that exists in the Universe today was formed in the first half of cosmic history, and the other quarter was formed later. Further back in space and earlier in time, 50% of the oxygen we have here today was formed in the first quarter of the history of the Universe, in the first 3.5 billion years after the Big Bang, when there were still about 5 billion years left. There are a few years left until the appearance of the Sun and the Earth, which in turn are another 4.5 billion years old. We do not provide more data on the formation of oxygen, although there is some, and we conclude that on average our oxygen may be about 10.5 billion years old. We are so old.

We are oxygen, carbon and hydrogen

If we continue to ask ourselves how old we are by counting when our constituent elements were formed, we must move on to the next type of atom in terms of mass contribution to our scale dimension. This element is carbon, which makes up almost 20% of our mass. Carbon, more oxygen, more hydrogen already make up 93% of our body mass. Carbon is a little more difficult to observe, but with a radio telescope we can penetrate almost as far and as early into the history of the Universe as we can with oxygen.

Until this point, it is more or less enough for us to calculate the real age of our body. We leave the formation of the other elements (nitrogen, calcium and phosphorus) as a small adjustment that we don’t want to go into. We do not stop at the fact that any atom actually comes from that primordial hydrogen that appeared in the first second of our Universe, mixed with teapots stellar, with the help of other very ancient particles such as photons (which were not always there).

For a planet, we could do a similar accounting, taking into account its atoms, where they came from and when they came into being. How does our age compare to the age of our planet in terms of the age of our atoms? A third of the Earth’s mass is iron, a little less is oxygen, and another third is dominated by silicon and magnesium, almost 15% of the mass each, leaving only room (or rather, mass) for small amounts of sulfur, nickel, and cadmium. , etc.

When did the iron or silicon that we have on our planet form? Well, the answer is much more difficult than in the case of oxygen. Iron can be detected in very distant objects, although this is extremely difficult. We have discovered iron and silicon near supermassive black holes that existed when the universe was 5% of its current age, but these elements certainly appeared much more slowly than oxygen: we need to continue research to confirm this.

Here we leave this journey through the history of our bodies. We do not go into detail when matter, which had been dancing in the Universe for thousands of years, came together in this way and became something that philosophy and religion have been trying to explain for several thousand years. Particles of our bodies have long filled part of the cosmic void and will return to it, although they fill it a little less each time.

Cosmic Void This is a section in which our knowledge of the Universe is presented qualitatively and quantitatively. Its purpose is to explain the importance of understanding space not only from a scientific point of view, but also from a philosophical, social and economic point of view. The name “cosmic vacuum” refers to the fact that the Universe was and remains largely empty, with less than one atom per cubic meter, despite the fact that our environment, paradoxically, contains quintillions of atoms per meter. cubic, which invites us to think about our existence and the presence of life in the Universe. The section has been compiled. Pablo G. Perez Gonzalezresearcher at the Astrobiology Center, and Eva VillaverDirector of the Space and Society Directorate of the Spanish Space Agency and Research Professor at the Institute of Astrophysics of the Canary Islands.

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