Wonders of the universe: Does the gold on Earth come from the crazy neutron star "alchemy"?

There is a fable called "Sun Mountain". It tells about a family with two brothers. The elder one is rich and the younger one is poor. One day, the younger brother went up the mountain to chop wood. While taking a break, he was worried about not being able to pay the rent for the elder brother. At this time, a big bird flew over and said to him, "Don't worry. I will carry you to Sun Mountain. There are a lot of gold, silver and jewelry there. You can improve your life if you pick some up."

The second brother sat on the big bird's back and soon arrived at Sun Mountain, where there were indeed a mountain of gold, silver and jewelry. The second brother took a small piece of gold and sat on the big bird's back. The big bird asked him why he took so little, and he said it was enough.

The second brother used the money from the gold to buy land and build a new house, and his life gradually improved. The eldest brother was surprised to see his younger brother's life suddenly improved, so he asked him the reason. The second brother told his brother that the big bird carried him to the Sun Mountain to pick up gold. After hearing this, the eldest brother pretended to go chop wood and sat there worried. At this time, the big bird came and carried him to the Gold Mountain.

Seeing the gold, silver and jewels all over the ground, the eldest brother's eyes lit up, and he took out the big bag he brought and filled it up greedily. The big bird told him not to take too much, otherwise he would be burned to death when the sun came back. The eldest brother hummed in response, and couldn't stop at all. At this time, the big bird shouted loudly, the sun is coming back! The eldest brother reluctantly got up, but he couldn't drag the almost full bag, and he was reluctant to throw some away. When the big bird saw the sun coming back, it flew away in a hurry, and the eldest brother was burned to death. This story tells people that if you want to get rich, don't be too greedy, otherwise you will lose more than you gain.

Of course, there are no mountains of the sun or gold on Earth, but there are mountains of gold in the universe, which come from the wonderful "cosmic alchemy" - neutron star collisions! Scientists believe that neutron star collisions are like large-scale alchemy furnaces in the universe, and are the source of the production of elements heavier than iron. Almost all the gold on Earth and in the universe is produced by neutron star collisions.

On October 16, 2017, many observatories around the world observed the first neutron star collision. The gravitational wave ripples of this event traveled at the speed of light for 130 million years and were received by the gravitational wave detection device on Earth. This discovery was named "GW170817". Scientists believe that this collision caused some debris from the neutron star to drift into space, including about 300 Earth masses of gold.

At that time, scientists believed that such a collision would occur once every 100,000 years, but this is not the case. On January 7, 2020, scientists observed gravitational waves from the collision and fusion of two neutron stars. This event was named "GW190425" and was 520 million light-years away from us. This shows that neutron star collisions are common events in the universe.

Neutron stars are ubiquitous in the universe. Scientific analysis shows that there are no less than 1 billion neutron stars in the Milky Way alone. More than 2,000 have been discovered so far, and my country's "Sky Eye" has discovered more than 800. However, because neutron stars are too small, with a diameter of only about 10 kilometers, and do not emit visible light, they are difficult to detect.

So, what is a neutron star and what are some of its characteristics?

In fact, neutron stars, like black holes and white dwarfs, are the remains of stars left in the universe after their death. They are extremely dense celestial bodies. Scientific analysis shows that, in general, stars with masses between 8 and 30 times that of the sun will explode as a supernova after death. Stars with masses less than 8 times that of the sun will collapse into a white dwarf after death. Stars with masses greater than 30 times that of the sun may collapse into a black hole after a supernova explosion. Therefore, neutron stars are dense celestial bodies between white dwarfs and black holes.

The diameter of a neutron star generally does not exceed 30 kilometers, and its mass is between 1.44 and 3 solar masses. This upper limit of mass is called the "Oppenheimer limit". If it exceeds this limit, it will collapse into a black hole under its own gravity; and 1.44 solar masses is called the "Chandrasekhar limit", which is the upper limit of the mass of a white dwarf. If it exceeds this limit, the white dwarf will collapse into a neutron star.

It can be seen from this that neutron stars with a diameter between 10 and 30 kilometers, equivalent to the size of a small or medium-sized city, cannot be seen in the universe at all. They can only be observed through radio telescopes or gravitational wave detectors through the electromagnetic pulses or collision gravitational waves they emit.

Since neutron stars are formed by the collapse of massive stars after their explosion, they inherit the angular momentum of stars and generally rotate very fast, with the fastest speed reaching more than a thousand revolutions per second. The magnetic poles of neutron stars are not in a straight line with their rotation axis, but at an angle. In this way, the electromagnetic pulses emitted by the rotating neutron star will sweep across space like a lighthouse, and in a very regular manner. When this electromagnetic pulse sweeps to the earth and is captured by a radio telescope, the neutron star will be discovered.

So far, neutron stars have basically been discovered in this way, and therefore this type of neutron star is also called pulsar.

The mass of the sun is about 2*10^30kg and its diameter is about 1.392 million kilometers. A neutron star with a diameter of 10 to 30 kilometers has about 2 solar masses. You can imagine how dense it is. It is generally believed that the density of a neutron star is between 100 million tons and 1 billion tons per cubic centimeter! The density of a neutron star is so high because of its extreme gravitational pressure, which crushes the atoms. The electrons are compressed into the nucleus and neutralized with protons to form neutrons. In this way, the entire star is mainly squeezed together by neutrons, and the density is equivalent to or even exceeds that of the nucleus.

What would happen if a small piece of neutron star debris came to Earth? This is impossible, because the neutron star matter is extremely dense, and it is extremely difficult to peel off a piece of matter from the surface of a neutron star. Once the neutron star matter is out of the strong gravitational pressure environment of the neutron star, it will explode and collapse into conventional matter.

Therefore, a neutron star will only be torn apart or merged when it collides with a neutron star or a black hole. The extremely strong pressure and trillion-degree high temperature will fuse matter into elements heavier than iron, and emit high-energy X-rays or gamma rays, and even emit a gamma-ray burst with the universe's top energy.

According to scientists' analysis, the first mass extinction event on Earth, the Ordovician extinction event that occurred 445 million years ago, may have been caused by the collision of two neutron stars 6,000 light-years away from us. A gamma-ray burst that burst out just hit the Earth, destroying the ozone layer of the Earth's atmosphere. The sun's ultraviolet rays attacked the Earth unscrupulously, causing the food chain to break and 85% of species to become extinct.

Therefore, neutron stars are an extreme existence in the universe. They can produce more matter for the universe, or they can purify the universe and destroy life. But scientists are convinced that the gold in the universe is basically thanks to neutron stars, and the gold on Earth also comes from "pie in the sky", because the conditions on Earth cannot form gold naturally.

According to media reports on February 25, the powerful Webb Space Telescope and its predecessor, the Hubble Space Telescope, recently jointly observed an ultra-long gamma-ray burst. This beam of energy erupted when two neutron stars collided millions of years ago. The results of telescope detection showed that the collision did produce "pure gold", which further confirmed that the gold in the universe mainly comes from neutron star collisions.

Eleonora Troja, an astrophysicist at the University of Rome who participated in the study, pointed out that this is the first time that it can be confirmed that metals heavier than iron and silver are "freshly" produced in front of us. The leader of the research team, Yu-Han Yang, said that neutron star mergers may create an ideal environment for the synthesis of heavy elements in large quantities, which is currently impossible to achieve artificially.

Therefore, we can be sure that there will be a lot of gold and silver mountains near the neutron stars that have collided. So, can people who want to get rich really go to the vicinity of neutron stars to pan for gold? The answer is of course no.

First, neutron star collisions occur in faraway places, billions of light-years away from us, and the closest ones are thousands or even millions of light-years away, while humans are currently far behind even one-ten-thousandth of a light-year; secondly, due to the extreme gravitational field of neutron stars, ordinary celestial bodies will be eaten if they approach, let alone weak creatures like humans.

According to calculations, if a person is attracted by a neutron star and falls to the surface, the fastest speed will reach half the speed of light, and the impact force is equivalent to a 200 million ton nuclear explosion, which is the explosion energy of the world's largest nuclear bomb to date - four Soviet-made Tsar hydrogen bombs. The shock wave of this energy explosion cannot even create a millimeter wave under the extreme gravitational pressure on the surface of a neutron star. The unfortunate person who falls on the surface of a neutron star will quickly be compressed into a pile of neutrons, smaller than a virus.

In this way, if there are really greedy people who insist on going there to make money, they will definitely end up like the greedy ghost who went to Sun Mountain to make money, and never come back.

However, this does not deny that the gold produced by the collision of neutron stars is beyond human consumption. The gold mines we dig and the nuggets we pick up now all come from the collision of neutron stars. In the early days of the Earth's formation, it was bombarded by meteorites for a long time, and a lot of gold hit the Earth and penetrated into the deep of the molten Earth at that time. Due to the effect of gravity, a large amount of gold was deposited in the deep core of the Earth, and a small amount was in the crust, which was discovered by humans.

Moreover, the gold floating in space will fall to the earth from time to time. If a large amount of gold formed by the collision of neutron stars is captured by the earth's gravity one day, the miracle of pie falling from the sky will really happen. What do you think? Thank you for reading and welcome to discuss.

This is an original article from Space-Time Communication. Please respect the author’s copyright. Thank you for your understanding and cooperation.

Information link:

https://www.msn.cn/zh-cn/news/other/%E5%AE%87%E5%AE%99%E7%82%BC%E9%87%91%E6%9C%AF-%E9% 9F%A6%E4%BC%AF%E5%92%8C%E5%93%88%E5%8B%83%E6%9C%9B%E8%BF%9C%E9%95%9C%E8%AF%81%E5%AE%9E %E4%B8%AD%E5%AD%90%E6%98%9F%E7%A2%B0%E6%92%9E%E4%BC%9A%E4%BA%A7%E7%94%9F%E9%BB%84%E9%8 7%91/ar-BB1iPYLr?ocid=msedgdhp&pc=EdgeStart&cvid=65dadaa72a26448798bd03c81c34779a&ei=18