Strange knowledge increased

This is a popular science book composed of 50 weird and wonderful scientific facts.

With the advancement and leaps of science and technology, mankind’s understanding of the world has been deepened, all of which have revealed a universe far more strange than we imagined. The author uses relaxed and humorous language to explain to us the huge energy hidden in the universe, and also reveals the interesting details about the existence of life, allowing people to gain a wealth of scientific knowledge while opening their minds. Unearthing the hidden truths that control our daily lives can help explain the enormous complexity of our existence, and can also change our way of thinking and perception of everything.

Light 30,000 years ago

Pleasant memories make me go back to the old days.

–Thomas Moore

There is a very magical photo in the history of science, with an orange, grainy light spot on the dark blue background. When I give lectures on popular science, I always like to project this picture on a big screen for everyone to guess. Some said it was an exploding star, some said it was an atom, and some said it was a molten metal ball. Anyway, the answer is strange, but few people get it right. This way, I can give this surprising answer in an exaggerated tone: “This is the sun! The sun at night.”

“You can get it,” someone will stand up and question, “at night? Isn’t the sun on the other side of the earth?”

“Yeah, it’s not the sun on the other side of the earth! This photo was not taken with your head up, but taken with your head buried. The sun on the other side of the earth was taken more than 8,000 miles across the diameter of the earth. This is not through It was taken by light, but by neutrinos.”

Neutrinos are subatomic particles that come and go without a trace. They are the product of nuclear reactions in the core of the sun. The number is incredible. Now if you extend your thumb, 100 billion neutrinos will pass through your fingernails in one second. You are unaware of this because they don’t like social interaction very much, and they don’t generally communicate with any atoms. To find its trace, you can only use a probe full of a large number of atoms, hoping which atom can stop a neutrino.

This photo of the sun on the back of the earth was taken by the Super Kamioka Neutrino Probe, which is buried deep in a large cave below Gifu Prefecture, Japan. The detector is like a 10-story can of braised pork, filled with 50,000 tons of water. Occasionally, a neutrino from the sun will pass through the detector and very rarely interact with the hydrogen nucleus in the water molecule, that is, the proton. Then the subatomic shrapnel is blown out of the water tank, and this process emits light like a supersonic shock wave. You have probably seen photos of this Cherenkov light, which are actually the blue shining light emitted by the radioactive waste next to the nuclear reactor.

In the huge can of the Super Kamioka Detector, 11,146 “bulbs” with a diameter of 50 cm are covered. They are light detectors called “photomultiplier tubes”. By recording which photodetectors are activated (detecting light) and the order in which they are activated, physicists can infer the path of the neutrino to produce Cherenkov light.

But these details are not important. As long as it is known that neutrinos hardly interact with other matter, they can walk unimpededly in a straight line when diverging from the core of the sun to the surface, and reach the surface of the sun in only 2 seconds. It then took another 8.5 minutes to fly to the earth.

Give your thumbs up again. The neutrino now passing through your thumb was still in the core of the sun about 8.5 minutes ago.

However, although sunlight is also produced by the nuclear reaction of the inner core, it is quite different from the encounter of neutrinos. Light is a stream of particles composed of countless photons, and their journey from the core of the sun to the surface is extremely difficult. The photons are like middle-aged women grabbing price-reduced goods at Christmas, blazing a trail in the crowded streets. They can’t walk in a straight line, and they can only move forward in a zigzag shape when they are squeezed to doubt their lives. In the interior of the sun, photons will be reflected in another direction by other matter when they travel less than one centimeter. In fact, for photons, the journey from the inner core to the outer layers of the sun is too tortuous, and it takes 30,000 years to complete. Yes, you read that right, it is 30,000 years! Thinking about the neutrino only takes 2 seconds, I can’t help but feel distressed about the photon. Then, it takes only 8.5 minutes for the photon to reach the earth from the outer layer of the sun.

In summary, the sunshine you see today is 30,000 years old, and they were almost born during the last ice age!


Dark matter is everywhere, it’s in every corner of your room.

——Fabiola Giannotti

97.5% of the universe is invisible. No matter what angle you look at, this is the most surprising discovery in the history of science. However, most scientists are still not deeply aware of this fact. Many people still don’t realize that the work that scientists have worked on for more than 350 years is only a very small part of the universe, just like snowflakes scattered in the lofty mountains.

Only 4.9% of the universe is made up of atoms, such as you and me, the stars in the sky, etc. However, through the telescope, we can only see half of this 4.9%. Astronomers suspect that the other half of the invisible matter, which is composed of atoms, is the gas wandering between galaxies. They are not cold enough or hot enough to emit light. Recent scientific studies have shown that we have found a part of this invisible substance in the hot gas filaments. Hot gas filaments are thin webs of matter between galaxies.

4.9% of the universe is ordinary matter, and 26.8% (about 6 times that of ordinary matter) is dark matter. Dark matter does not emit light, or the light it emits is so dim that it cannot be detected by our most sensitive astronomical equipment. We can perceive the existence of dark matter entirely because dark matter has a gravitational effect on visible stars and galaxies, making their trajectories inconsistent with the calculation results of Newton’s law of gravity.

As for what dark matter is, I don’t know much more than you. There are many speculations about this, from unknown subatoms to refrigerator-sized black holes that have existed since the Big Bang. Another possibility is that we are in a backward time, and dark matter is a legacy of the future (no kidding). If dark matter is composed of the former, then it is really flooding the air around you now. Scientists also hoped that subatoms of suspected dark matter would show up in a large particle accelerator near Geneva, Switzerland, but so far there have been no surprises. When I have nothing to do, I will guess whether there will be dark stars, dark planets, dark creatures and the like. It is also speculated that the reason why scientists have been trying to find alien civilizations in the past 50 years but have found nothing may lie in these “dark” things. Maybe there are lively inter-galaxy business and cultural exchanges around us, but we can’t see it.

Excluding 4.9% of ordinary matter and 26.8% of dark matter, dark energy accounts for 68.3% of the mass of the universe (remember, all energies have equal masses, converted according to Einstein’s mass-energy equation E=m). Dark energy is invisible, it fills the universe and has negative gravity. Negative gravity will accelerate the expansion of the universe, which is why we were able to discover the existence of dark energy in 1998. Imagine that until more than 20 years ago, the scientific community began to realize that most of the universe has been ignored.

If physicists are stumped by dark matter, then dark energy simply makes them impossible to start. The most advanced physical theory today is quantum theory. It is very successful. We have obtained lasers, computers and nuclear reactors from it. It also explains why the sun shines and why the ground under our feet is solid. However, when we use quantum theory to predict the energy of dark energy, the calculated result is as large as 1 plus 120 zeros after the actual observation. This is the biggest difference between the theoretical value and the observed value in the history of science. Maybe we have some misunderstandings about the meaning of “real world”.

“The most embarrassing problem facing modern cosmology is that most of the composition of the universe is invisible,” said American astronomer Stacy McGow. “Dark matter and dark energy constitute about 95% of the universe’s mass and energy, but we I just know that they exist.”

Quietly think about it, we actually only rely on 2.5% of the universe seen in the telescope to outline the cornerstone of modern cosmology, that is, the universe model. For example, it’s like, if Charles Darwin in the 19th century only knew about frogs but didn’t know about trees, dogs, grasshoppers or sharks, then he could do in biological theories, such as the theory of evolution. How many achievements have been made? Modern astronomers are in this awkward position. Obviously, modern cosmology is missing a large piece of knowledge. I hope that someday, new discoveries can make up for these blind spots, so that dark matter and dark energy, the troublemakers in the Big Bang theory, can be organically integrated into a perfect theory. Hopefully, there will be surprises waiting for us along the way of science-the kind of surprise that can completely change the way we view the universe.

You are indeed from heaven

In my heart, a curved blade of grass can rise and fall like the stars in the sky.

-Walt Whitman

The iron in your blood, the calcium in your bones, and the oxygen inhaled in your lungs were all formed inside the stars long before the earth was born. In fact, the relationship between us and the galaxy is so close that no astrologer can imagine it, and the path for scientists to discover this amazing fact is long and tortuous.

The first step is to discover that everything in the universe is composed of atoms. Richard Van Mann once asked a question: “If there is a catastrophe, all science and technology will be destroyed, but we can only leave a word for future generations, so how can we use the least words to convey the most scientific information? He asked and replied categorically: “Everything is made of atoms.”

In the long centuries, people have continuously tried to refine one substance into another, such as turning lead into gold. Interestingly, after hundreds of years of unsuccessful attempts, people suddenly discovered that the world is made up of tiny indivisible particles, and these elementary particles cannot change from one kind to another. Atom is not only a basic element, it is also the alphabet that composes everything. As mentioned above, combining atoms in different ways and different types can form a galaxy, a tree, or an ape playing in the mountains. The complex and changeable things in the world are just illusions, and the essence of everything is very simple, just the arrangement and combination of the basic elements of nature.

There are 92 kinds of naturally occurring atoms or elements in nature, ranging from the lightest hydrogen element to the heaviest uranium element. Some of these elements are common in the universe, while others are not. In the 20th century, we discovered another weird fact. The amount of an element in the universe is related to the structure of its nucleus. For example, the lightest element in the nucleus is the most common.

So, why is the content of the element in the universe related to the structure of the element’s nucleus? The only workable explanation is that the nuclear reaction process is also involved in the process of atom formation. In other words, the God of Creation did not create these 92 elements all at once. The reality is that when the universe was still in its infancy, it only had the simplest atom-the hydrogen atom. The other heavier elements are formed by the combination of hydrogen.

The repulsive force between the protons in the nucleus is extremely strong. If you want to rely on nuclear force to bind and bond them like the “traction beam” in “Star Trek”, you must place the protons close enough. This means that the protons must “bang” together at a very high speed. Temperature is a measure of microscopic movement, which means that this nuclear reaction requires extremely high temperatures.

The question faced by physicists in the 20th century is: Where in the universe can the temperature reach the high-temperature furnace where atomic nuclei fuse to form new atoms? At first, scientists thought it was the surface of the major stars, but even the temperature there did not seem to be high enough. They found that they had found the wrong place, so they turned their attention to the moment when the universe was born: the fireball of the Big Bang was the original melting pot.

However, it is not so easy for nature to do things. The cosmic melting pot for refining 92 elements does not stop here. Some elements with extremely light masses, such as helium, were indeed refined in the first few minutes of the birth of the universe. And all the heavier elements are derived from the painstaking efforts and laborious refinement of the cores of each star since the Big Bang.

A star like the sun is not hot enough and dense enough to refine any element heavier than helium. But the inside of massive stars can produce atoms as heavy as iron. In the end, the internal structure of this type of star is like an onion, and the constituent elements of each layer are heavier than the constituent elements of the outer layer.

If these stars remain stable and have not evolved to the stage of supernova explosion, then these new and heavier elements have been locked in the interior of the star. In this way, we won’t exist anymore. Fortunately, these stars will not only use their own explosions to share the new elements fused in the nuclear furnace with the entire universe, they will also produce heavier elements during the explosion.

These elements are mixed with the gas and dust of the interstellar cloud, enriching the heavy mass elements in the interstellar cloud, and together with the interstellar cloud, they give birth to new stars and planets. Because of this, the heavy elements will appear on the earth. As American astronomer Alan Sandage said: “We are all brothers and sisters, we are all from the same supernova explosion.”

What would it look like if a small piece of matter was dug from a star? If you are curious, you might as well raise your hand and take a look, after all, you are transformed by stardust