The Earth is home to nearly 100 natural elements, all of which existed at the dawn of the Earth, about 4.6 billion years ago. It is precisely such a rich and colorful element that makes the earth have rich topography and a colorful life world, and can give birth to human beings, a high-level intelligent species.
Heavy metals are very common in our daily life, even in our human body, they also contain heavy metals, such as iron, zinc, copper, manganese, cobalt, selenium and other heavy metals. These heavy metals are involved in the activities of a variety of enzymes in the human body, regulate metabolic processes, and maintain the normal function of the body, so it is very important to supplement these elements in an appropriate amount to maintain health.
So, you don't think about where these heavy elements come from, how they were formed in the first place, why are the heavier elements in less place? For example, heavy metals like gold, silver, and platinum are very small.
To know the answers to these questions, we need to travel back tens of billions of years to the beginning of the universe.
The mainstream scientific theory is that our universe originated from the Big Bang 13.8 billion years ago, also known as the Big Bang theory, and everything we see today was the result of the Big Bang. And in the 13.8 billion years of the universe's long evolutionary history, the first three minutes are extremely important.
Scientists say that the sum of the events that occurred in the first three minutes of the Big Bang far exceeded the sum of the events that followed in the next 13.8 billion years! It is hard to imagine the complex evolutionary process that underwent in the first three minutes, and it was the first three minutes that laid the foundation for the 13.8 billion years of cosmic evolution.
At the beginning of the universe, the elements formed were actually very limited, with only hydrogen and helium being the two lightest elements, most of which were hydrogen. In the long years that followed, the universe was like a "super melting pot", constantly "forging" heavier elements, and starting an extremely long "creation journey". Elements such as hydrogen and helium collide with each other and fuse to form heavier elements, so what is the specific process?
Two words: star!
We have to thank the stars, because they are the melting pot of the elements.
Only hydrogen and helium were in the state of two elements in the universe for a long time, about 100 million years! Then, as the temperature of the universe continued to drop, hydrogen and helium began to merge, and the driving force of the fusion was gravity, or "unbalanced gravity" to be precise.
We all know that gravity is everywhere, but if the gravitational pull of the universe were balanced, elements such as hydrogen and helium would not have come together under gravity at the beginning of the universe, but would have been in balance with each other.
However, there is no perfect universe in absolute equilibrium, and due to the difference in temperature density in the universe, the gravitational attraction in a certain area of the universe will be slightly larger, so under the action of gravity, more matter (gas clouds) will be attracted to continuously accumulate.
The gas cloud that gathers brings more mass, which also means more gravity, which in turn attracts more gas clouds. This process repeats itself like a snowball, with more and more gas clouds coming together faster and faster, and the mass and gravitational force will continue to increase.
The temperature and pressure at the core of the gas cloud will become higher and higher, and at a certain tipping point, it will trigger one of the most important events in the universe: nuclear fusion. It also announces the birth of stars.
Nuclear fusion, on the other hand, is the process by which hydrogen is fused into a heavy element. Take our sun, for example, the core temperature of the sun is as high as 15 million degrees, and the pressure reaches 250 billion times the atmospheric pressure of the earth, under such high temperature and pressure, hydrogen converges into helium, and then heavier elements such as carbon and oxygen.
Stars with greater mass can fuse heavier elements. But the fusion of stars does not last forever, and once the fusion reaches the element of iron, the fusion of stars comes to an abrupt end, or the star dies. Why?
To put it simply, because iron is the most stable element, iron has the highest specific binding energy.
Let's first understand the concept of "binding energy". We all know that the nucleus of an atom is made up of nucleons such as protons and neutrons, and that the energy that is held together by a strong nuclear force between protons and neutrons is the "binding energy". If you want to separate the nuclei, you need strong energy to counteract the "binding energy" between the nuclei.
To put it bluntly, it's nuclear energy.
The specific binding energy is the ratio of the binding energy to the number of nucleons, which is equivalent to the relationship between GDP and GDP per capita. The greater the specific binding energy, the more stable the element is. Iron has the largest specific binding energy and is therefore the most stable.
Elements that are lighter than iron release energy during fusion. In order for an element heavier than iron to fuse, it does not release energy, but instead absorbs it.
And we all know that stars have been stable for billions of years because the energy released during nuclear fusion is in equilibrium with the gravitational pull generated by themselves. If the fusion process no longer releases energy, there is no force to balance with gravity, and the result is that gravity is completely out of control, and the star begins to collapse sharply under gravity, effectively announcing the death of the star.
But not all stars can be fused to iron, for example, our sun, because the mass is not large enough, because the core pressure and temperature are not enough, is not enough to fuse iron. But when scientists analyzed the solar spectrum, they found that the sun contains more important elements than iron.
The only explanation is that these heavier elements than iron existed in the first place, and were not created by the sun's nuclear fusion. So where did the heavy elements that existed in the beginning come from?
And then the death of the stars. The death of a star does not mean the end of elemental fusion, although elements heavier than iron need to absorb energy when they fuse, but if there is really enough energy, elements heavier than iron can continue to fuse.
After the death of a star, it will collapse sharply inward under the action of gravity, especially for massive stars, and the collapse process is even more violent. The massive stellar material that continues to hit the inner core of the dead star as it collapses inward, bringing enormous energy to the inner core, and the temperature and pressure rise sharply, enough to trigger a new round of fusion, and the elements heavier than iron will continue to fuse.
This is actually a supernova explosion, which is the patent of massive stars. During the supernova explosion, super energy is released in just a few seconds, which is ejected in the form of high-energy particles, and the impact is very wide. In the end, only the dense inner core, that is, neutron stars and even black holes, will be left behind, and the matter outside the inner core will be thrown into the vast interstellar space to become the raw materials for the next generation of stars and planets, mainly light elements.
And our sun is formed by constantly gathering these raw materials, which is why scientists find a small number of elements heavier than iron on the sun, because the sun is not the first generation of stars, but the second or third generation of stars (scientists are not sure, but certainly not the first generation), and the heavy elements on it only inherit the material of the first generation of stars.
Scientists once thought that the more important elements than iron were produced by supernova explosions, but later found that it may not work theoretically, which is not to say that supernova explosions cannot produce heavy elements, but that they cannot produce enough heavy elements.
Because heavier elements than iron are produced mainly by capturing neutrons, beta decay, it is theoretically possible for a supernova explosion to produce a large number of heavy elements in a short period of time, but it is actually difficult to work due to the lack of enough neutrons.
While observing another major cosmic event, astronomers discovered another way of generating heavy elements: neutron star collisions. Neutron stars are dense cores that occur after the death of massive stars and are very dense. Another feature is that neutron stars usually appear in binary star systems, which means that two neutron stars orbit each other. In the process of operation, it is inevitable that collisions will occur due to various unknown factors, and the collision will release super energy and a large number of neutrons, which is enough to produce a large number of heavy metals in a very short time, such as gold, silver, platinum, etc.
summary
All life on Earth is carbon-based, and it took nature 100 million years to create carbon, and then it evolved over a long period of time to create elements heavier than iron through stellar nuclear fusion, supernova explosions, and neutron star collisions.
In a sense, everything in the universe that you and I see every day, is actually "nuclear waste", because almost all elements come from dead stars, to be precise, from the "ashes" of dead stars, and neutron stars are the "graves" after the death of massive stars.
Looking back at the entire evolutionary history of stars again, we can only use the word "tragic" to describe it, but there is no lack of new forces in the tragic. Every death of a star means a new life, the rebirth of a young star. Heavy elements such as gold and silver buried in every corner of the universe seem to tell the story of the cosmic events that were staged countless times billions of years ago.
And each of us is actually a witness to the long evolutionary history of the universe, because every element in our body comes from billions or even tens of billions of years ago stars!
Finish!