In 527, at the time when the Eastern Roman Empire ruled Syria, soldiers discovered in an alcove there existed a lamp covered with a very sophisticated hood. According to history books, this lamp was lit in the year 57, which means that the lamp has been burning for nearly 500 years. Another lamp above the door of the temple of the sun god in Egypt is also recorded by Greek historians. The lamp does not use any fuel and still burns brightly for centuries, despite the impact of rain and wind. The oldest lamp was discovered in the 1400s, in the tomb of Pallas, son of the ancient Roman king Evandra. Thus, this lamp has so far burned brightly for more than… 2,600 years. To date, scientists have not been able to get an exact answer for that strange black chemical. In 1534, King Henry VIII’s army stormed the English synagogue, disbanding religious groups and excavating numerous graves. While digging through the grave of the Roman emperor Constantin’s father in Yorkshire, they discovered a burning lamp. This king’s father died in the year 300, which also means that the lamp was found to have a “life expectancy” of more than 1,200 years? These are just a few of the many millennial lights that do not go out. Records show that this mysterious phenomenon occurs all over the world, typically in countries and regions with ancient civilizations such as India, China, Egypt… The strange thing is that these mysterious lights are not preserved and preserved for the next life. Many researchers believe that, at that time, there were so many eternal lamps that they did not need to be preserved, so they did not have measures to preserve these “forever” finds. According to records, in fact, ancient people also thought of preserving these lamps, but strangely, shortly after being discovered, they were quickly destroyed by various causes. The scholar Saint Augustin (354-430) described an eternal lamp in the temple of Isis (Egypt). The most confusing thing is that it is located in the roofless part, despite the wind and rain. Similarly, the lamp in Edessa (Syria) burned for 500 years in extreme weather conditions. In 1300, the “special oil” theory was partly clarified, when the researcher Marcus Grecus wrote in his Liber Ignum (Book of Fire) that some eternal lamps used special fuels. It wasn’t oil but just a fine powder made from “glow worms”, but what kind of worms Marcus didn’t know and the mystery was forever buried. Marcus only said that “I looked at the wick, it was as long as my arm. A long time later, I came back and it was the same length, no one changed the wick or added more flour.” In 1401, in the grave of Pallas (son of King Evandra – Roman), people found an eternal lamp and said it had burned for 2,600 years. To put it out, according to the elders, there is only one way to break it all or pour out its “oil”. In 1450, a farmer in Padoue (Italy), while plowing his field found an earthenware vase, followed by two small metal vessels, one of gold and one of silver. In these two jars was a strange slime, half oil, half honey. Inside the terracotta vase was another terracotta vase containing an eternal lamp that was still burning. Buried underground (since when) and burned in such low oxygen conditions, it is a mystery. In 1610, researcher Ludovicius Vives claimed to have seen an eternal lamp (burning for 1,500 years) and was smashed by potters. The historian Cambden (England) in 1586 also mentioned an eternal lamp at the grave of Constantius Chlorus, father of Constantine the Great. Chlorus died in 306 in England and since then, an eternal lamp has been placed in his grave. In Spain, there was also an eternal lamp found at Cordone in 1846. Priest Evariste – Regis Huc (1813-1860) was an avid traveler in Asia and found such an immortal lamp in Tibet in 1853. The above findings prove that these mysterious lamps are not the product of Greece, Egypt or Rome alone. Chemist Brand (Hambourg – Germany) in 1669 determined that these eternal lamps burn for so long because of phosphorus. Others believe that they burn for a long time because they do not need air, on the contrary, if exposed to air they will extinguish. If this opinion is true, could the ancients know the vacuum technique? Besides, fire burns without oxygen is a very difficult thing to understand. These debates force people to turn to another mystery: the Egyptian lighting technique. On the streets of ancient Egypt, people used oil lamps and torches. Fuels are residues that are rich in fats and oils. But in the crypts dug up to 100 meters into the mountains, what light did the slaves and sculptors work with? In these catacombs, there was no trace of any lamps or torches. So did the Egyptians use mirrors to reflect sunlight? But the “mirrors” of that time were only silver, and could only reflect 40% of the light, meaning that at a depth of a few tens of meters, darkness would completely cover again. A shocking discovery has shocked the archaeological world: at the temple of Hator in Denderah, built more than 4,200 years ago, there are drawings showing that the Egyptians “used strange instruments that looked like light bulbs. electricity today!”. Is this the mysterious light technique? Scientist Erich Von Daniken (Germany) is trying to recreate these giant light bulbs in the lab, but has not found the core of the problem. Egyptologists also conceded defeat, because apparently there was no electricity at that time. With such records of “forever-on” lamps being discovered around the world, it may be confirmed that these mysterious lamps do indeed exist. However, the manufacture and use of them is still a mystery to mankind and the scientific world.

Exploring the stars is man’s way to the universe. Some people think that each star represents a destiny, others say that the stars are small angels tasked with lighting up the night. Today, science has been able to give us a more precise answer. What is a star? Stars are all celestial bodies that are capable of emitting their own light. All of them are giant air spheres. They are tens to hundreds of thousands of times more massive than Earth. Only thanks to such a large mass can they create their own light. An object to be able to emit its own light needs to have a mass of at least 70 times the mass of Jupiter – the largest planet in the Solar System, that is, about 7% of the mass of the Sun. Why do we see the stars? The stars in the sky have always been a mystery to the human imagination. Our Earth has a mass of about 6x1024kg (6 million billion billion tons). The Sun is 330,000 times heavier than the Earth. That is, a star with a mass of 7% of the mass of the Sun would be about 23,000 times heavier than the Earth. Every object has a gravitational force that directs the center of it to its heart. Normally no one notices but we ourselves are always attracted to our own. Because each part of the body is attracted to each other and the sum of them all form a gravitational force directed towards a center of mass in our body (the center of gravity of the object). The table, the chair, the Earth, are always gravitating to itself by a force called centripetal gravity. But why doesn’t it all burn brightly? That’s because the mass of the objects we come into contact with every day just can’t afford that. Because gravity is a force proportional to mass, gravity in everyday objects is so small that they don’t cause any significant effects. With very large objects such as planets, Earth, gravity is also negligible because it creates a clear attraction that pulls everything towards it. For example, when you jump high, you will fall very quickly because of the pull from the Earth. As for the aforementioned massive objects (tens of thousands of times heavier than the Earth), the great gravity makes the pressure at the center of the celestial body very high, this pressure provides a great acceleration for the celestial bodies. gaseous atoms (mostly hydrogen). They collide strongly with each other at high velocities, breaking the electron shells, separating electrons from the atomic nucleus. At the core of the star is no longer ordinary gas but a state of chaotically moving nuclei and electrons. This state is called plasma. In the plasma state, the hydrogen nuclei have a chance to collide directly with each other at high velocities, which causes what we call fusion reactions, fusing hydrogen nuclei into heavy hydrogen and finally is the helium nucleus. This reaction is known on Earth in hydrogen bombs – bombs capable of releasing thousands of times more energy than atomic bombs of the same mass. The fusion reaction at the core of a star releases a lot of energy in the form of radiation, some of which is visible light. This radiation is transferred to the star’s surface and causes the star to glow. Stars are composed mainly of hydrogen (over 70%), with a large part helium remaining, and an insignificant fraction of heavier gases. The surface temperature of a star is usually in the range of 3,000 to 50,000K, and the temperature at the center is in the range of several million to several tens of millions of K. It can be as high as 100 million K for red giants and several billion K. with red supergiant stars. Star classification Graphic image. By mass, stars are divided into two types, dwarfs and giants. Today, modern division is based on spectral charts. In which, the star with the obtained spectrum of which position on the chart will be determined to belong to which group with specific characteristics of mass and temperature. The most widely used spectrogram today is the Hertzsprung-Russell chart. This graph represents the luminosity, size, and temperature of any star when its spectrum is obtained. According to temperature, the chart is divided into 7 levels with the symbols O, B, A, F, G, K, M respectively. In which, the star closer to O is hotter and closer to M is cold. Each level itself is divided into several sub-levels. Through the chart, it can be seen that most of the stars in the universe are concentrated in the main sequence of the chart. This sequence is a sequence of dwarfs and subgiant stars. Our sun is also on this sequence. It is located in the G group, has the detailed spectral designation G2V (yellow dwarf/Yellow dwarf). Below the sequence are groups of white dwarfs, and above are giants and supergiant, supergiant stars. Star evolution All stars form from large clouds of dust and gas called protostar nebulae. Due to gravity they gather together and shrink until they form a dense mass. As we all know, all objects that carry mass carry gravity. The same object itself also has a force of attraction between different parts of it. However, the gravitational force between small masses is negligible and we hardly notice it. Only significant forces, such as Earth’s gravity acting on people and objects, are enough to be noticed. In stars, gravity is very strong (due to its high mass). When the force of gravity is too great for the atoms to bear, they break the atomic shells and accelerate their nuclei. Hydrogen nuclei (consisting of 1 proton) when collided at high velocity, combine to form heavy hydrogen, and then helium. This reaction releases energy that causes the star to burn brightly. This is a fusion reaction (also known as a nuclear explosion. This reaction is used in the hydrogen bomb (H bomb) – the most destructive destructive weapon that mankind has built). Thanks to the great energy released from nuclear fusion in the star’s core, the gravitational contraction is halted as the released energy balances the gravitational force. The star burns so brightly for several tens, hundreds of millions or billions of years. The lower the mass of the stars, the longer the lifespan. For example, our Sun is a dwarf, medium mass, it can live for about 10 billion years. Meanwhile, stars are much larger, sometimes only living a few hundred or even tens of millions of years because the high mass creates greater pressure towards the center. It causes nuclear fusion to happen faster and the star to deplete energy faster. After burning out all of its hydrogen energy, the star no longer produces energy against centripetal gravity. It will once again shrink. At this time, the helium nuclei combine to form nuclei of heavier elements such as carbon, oxygen and heavier elements up to iron. This process releases an energy that inflates the star’s crust while the star’s core continues to contract. This is the red giant stage. For medium-sized stars (with a mass between 0.5 and 10 times the mass of the Sun), the red giant shell, when inflated sufficiently large, will explode and break up to form a planetary nebula. Meanwhile, high-mass stars have massively inflated stellar shells, becoming red supergiant stars. During this stage, the stellar core continues to contract due to gravity, temperature and pressure both increase many times compared to the previous stage, allowing nuclei of heavier elements to be synthesized (from familiar metals). from copper, silver, and gold to radioactive elements). Up to a certain limit, the energy released from the core creates a large explosion that breaks the outer shell. This is a supervova explosion. After the shell is broken, the star’s core remains for both massive stars as well as light stars. For low- and medium-mass stars like the Sun, the core will stop shrinking, becoming a white dwarf, emitting a very faint light. After billions or tens of billions of years, the generation of radiation ends, stars no longer emit light. It’s called a black dwarf, a dark, dead mass of matter. In fact, the process for a white dwarf to become a black dwarf is so long that so far a black dwarf is only a theoretical prediction. No white dwarf in the universe has been around long enough to become a black dwarf. For massive stars whose core remains after the supervova are at least 1.4 times more massive than the Sun, the mass is so great that they continue to shrink. The nuclei react with each other to form heavy nuclei. The contractions are not over yet, they cause the free electrons to be squeezed tightly against the protons, combining to form neutrons. The star becomes a solid mass of matter, composed entirely of neutrons. Therefore, it has extremely high density and extremely fast rotation speed. This object is called a neutron star. Previously, when this object was first observed, astronomers saw that it emitted a very strong amount of electromagnetic pulses, so they called them pulsars. Even more massive stars with a core mass at least 2 or 3 times that of the Sun, have not stopped after reaching the neutron star stage. They squeeze all matter together to an infinitely large density, concentrated at a location called a singularity. This singularity warps the space around it, a region of space that is bent to an infinite (closed) curvature. The boundary of this space is called the event horizon. Because the space is bent inward, anything that goes in can’t get out, not even light. This entire region of space bounded by the event horizon is called a black hole.