The Sun’s atmosphere can be as hot as 1 million degrees Celsius. This increase in temperature, despite the increased distance from the Sun’s primary energy source, has been observed in most stars. In 1942, Swedish scientist Hannes Alfvén hypothesized that the magnetizing waves of plasma could carry large amounts of energy along the Sun’s magnetic field from the interior to the corona, passing through the photosphere. before exploding with heat in the upper atmosphere of the Sun. This hypothesis has been tentatively accepted, but there is no evidence that these waves exist. Recent research by scientists finally confirms Alfvén’s nearly 80-year-old hypothesis and brings us one step closer to harnessing this high-energy phenomenon on Earth. The sun is made up almost entirely of plasma Halo problems have been around since the late 1930s, when the Swedish spectrographer Bengt Edlén and the German astrophysicist Walter Grotrian first observed phenomena in the sun’s corona that could only be observed. present if its temperature is a few million degrees Celsius. This represents temperatures up to 1,000 times hotter than the photosphere below it, which is the surface of the Sun that we can see from Earth. Estimating the heat of the photosphere has always been relatively simple: we simply measure the light reaching us from the Sun and compare it with spectral models that predict the temperature of the light source. Through decades of research, the temperature of the photosphere has always been estimated to be around 6,000°C. Edlén and Grotrian’s discovery that the Sun’s corona is much hotter than the photosphere – albeit farther from the core. of the Sun, its supreme source of energy – has given the scientific community a headache. Scientists looked at the properties of the Sun to explain this difference. The sun is made up almost entirely of plasma, which is a highly ionized gas that carries an electrical charge. The movement of this plasma in the convection zone – the upper part of the sun – generates enormous electric currents and strong magnetic fields. These magnetic fields are then pulled up from the Sun’s interior by convection, and enter its visible surface in the form of sunspots, which are clusters of magnetic fields that can form a variety of magnetic structures. differences in the Sun’s atmosphere. Alfvén reasoned that within the Sun’s magnetized plasma, any large movement of charged particles would perturb the magnetic field, creating waves that could carry enormous amounts of energy across vast distances. (from the surface of the Sun to its atmosphere). Heat travels along what is known as a flux tube from the sun before bursting into the corona, creating its high temperature. Measure the temperature of the Sun with an imaging spectrometer These magnetic plasma waves are now known as Alfvén waves, and the explanation for the heating of the circle led to Alfvén being awarded the 1970 Nobel Prize in Physics. The Interferometric Bidimetric Urban Spectrometer (IBIS) for imaging spectroscopy, installed at the Dunn Solar Telescope in the US state of New Mexico. This instrument has allowed researchers to make more detailed observations and measurements of the Sun. Combined with good observational conditions, advanced computer simulations, and the efforts of an international team of scientists from seven research institutions, they used IBIS to confirm the existence of waves for the first time. Alfvén in flux tubes from the sun. The researchers also expect more solar discoveries soon, thanks to new, groundbreaking missions and tools. The European Space Agency’s Solar Orbiter satellite is currently in orbit around the Sun, providing images and making measurements of the star’s unexplored polar regions. The launch of the new high-performance Solar telescope is also expected to enhance our observation of the Sun from Earth.

Many facial sunscreens are formulated to reduce oiliness and are often more expensive than body products. “But the higher price doesn’t mean it offers better protection,” says Kimberly Jerdan, a board-certified dermatologist in the US. Here’s her advice on how to choose the right sunscreen for your face. Use a broad spectrum sunscreen When buying any sunscreen, there are two main signs to look for. Make sure the bottle says “broad spectrum”. Also, choose one with at least SPF 30. Choose a sunscreen that says “broad spectrum”. Photo: UChicago Medicine. Broad spectrum means the sunscreen protects the skin from both UVA and UVB rays. UVA rays cause premature aging, wrinkles and dark spots, they penetrate deeply and can damage the skin’s collagen. Meanwhile, UVB rays mainly damage the surface of the skin and cause sunburn. Both UVA and UVB can cause skin cancer. SPF (Sun Protection Factor) is an indicator of how much UVB radiation a sunscreen can filter out. SPF 30 sunscreen blocks 97% of the sun’s UVB rays. A higher SPF provides only a small amount of additional protection and needs to be applied frequently – every two hours. SPF does not measure protection from UVA rays. That’s why you need to make sure your sunscreen has a broad spectrum label to get protection from both. “Higher SPF sunscreens tend to be a bit more expensive. So I’d recommend saving money and just getting into the habit of reapplying every two hours,” says Jerdan. Based on how oily or dry your skin is Finding the right sunscreen can take some trial and error because everyone’s skin is different. If you have oily or acne-prone skin, Joyce Park, a dermatologist in the Bay Area (California, USA) recommends looking for creams labeled “non-comedogenic”. Because they will not clog pores, reducing the risk of acne. Pay attention to choose the right ingredients for your skin type. Photo: Tsww. Park also recommends sunscreens that contain niacinamide. This is a B vitamin that improves the appearance of the skin and reduces sebum production. For dry skin, she recommends looking for moisturizing ingredients like ceramides, hyaluronic acid, or glycerin. Apply sunscreen before makeup Currently, foundation creams also include SPF 30. However, they are often not applied much when wearing makeup. This limits sun protection. “Studies show that people don’t wear enough SPF makeup to get skin protection benefits,” says Dr. Park. So we recommend applying sunscreen to your face before applying makeup. Facial sunscreens are formulated to create different foundations – mist, matte or tinted. So it’s guaranteed to fit into any makeup routine.” Apply sunscreen before applying makeup for full protection. Photo: girlstyle.com Physical sunscreen for sensitive facial skin There are two main types of sunscreens, physical and chemical. Both protect the skin from UV radiation, they just contain different ingredients. It is these different ingredients that will help you choose the right sunscreen for your face. Physical sunscreens are formulated with zinc oxide or titanium dioxide. These are great options for people with sensitive skin because they are hypoallergenic. Another reason mineral sunscreens are ideal for the face is that they reduce the risk of hyperpigmentation and melasma. Jerdan says chemical sunscreens absorb the sun’s rays, so they can warm the face. Therefore, for those who are prone to tanning, it is best to avoid them. “Physical sunscreens can sometimes leave a thick layer of powder on the skin,” says Park. “But over the years, products have improved a lot and that’s no longer the case.” People with sensitive skin should use physical sunscreen. Photo: NBC. Chemical sunscreen Chemical sunscreens absorb the sun’s rays instead of reflecting them back. Jerdan advises patients with sensitive skin to “say no to benzones”. Avobenzone and oxybenzone commonly found in chemical sunscreens can cause allergic reactions. However, not all chemical sunscreens are based on these ingredients. The product still works fine if you are not allergic to it. Chemical sunscreen ingredients are also controversial due to a recent study conducted by the US Food and Drug Administration (FDA). Results showed that these compounds were absorbed into the skin and detected in the blood at levels above the FDA recommended threshold. However, this does not mean that chemical sunscreens are unsafe, researchers and dermatologists stress. Chemical sunscreen will still work as long as you’re not allergic to it. Photo: Freepik.

Illustration. To protect your eyes from sunlight: Sunglasses should be large enough to protect your eyes from the harsh sun. To reduce glare: Polarized glasses help reduce glare and help your eyes see better, especially when on the road. To prevent cataracts: A pair of sunglasses with UV protection is exactly what ophthalmologists specialize in at all times of the year. Let people…don’t recognize you: Sunglasses are often an integral part of Hollywood stars, it makes them look completely different, whenever they want to be quiet or relax on the street and don’t want others to notice. You may not be a star, but there will definitely be times when you want to be alone and not want anyone to notice. To hide the…you cried: Do not want others to notice your red eyes because you just cried, you can wear a pair of dark-colored sunglasses. Very effective. For a more “cool” look: Sunglasses come in a variety of styles and colors, and you can easily pair them with different outfits. It looks very “cool”. To avoid wind and dust: Sunglasses work best in case you are riding a motorbike. To protect your eyes while playing sports: It may sound strange, but a pair of anti-collision sunglasses can protect your eyes very effectively when playing sports. To highlight the face: Sunglasses can very well overcome some disadvantages of the face. And whether your face is round, square, or oval, there’s the right type of sunglasses for you. To look stylish: For many people, this is the primary (and sometimes only) use of sunglasses. Which color should I choose? Our skin color and eye color are also important in blocking UV rays. The darker the skin color, the better the UV filter. As for sunglasses, the UV filterability depends on the color of the glass and the material of the glass. Glass made of polycarbonate, CR39 has the ability to filter about 50% of UV rays. Amber yellow and light black are said to be the best UV filters. Blue light or groups of high-energy rays in the visible spectrum have been implicated in macular degeneration. Copper-colored, sepia glass is said to filter out blue light better than other colors. If you are in doubt, consult a spectrophotometer who will tell you exactly if your glasses are 100% UV protected. Gray is the most popular color among Americans. Gray glasses are used to be suitable for all normal activities while ensuring good vision, true colors. Brown is preferred by golfers and skiers. Orange should be used for shooters, red is suitable for places that are too sunny. Yellow should be used when driving and going to the beach. Indispensable beauty accessories Just like shoes, bags, sunglasses are also people’s favorite fashion items. The discreet, famous people who do not want to be scrutinized by the public also often wear large-framed sunglasses. Sunglasses are also cosmetic tools for people with eye disabilities. They can cover the deformities, increase their own aesthetics. More options when using sunglasses Sunglasses can be mirror-coated to prevent glare. New forms of materials are considered good scratch resistant, but quite expensive. Anti-glare glasses for drivers, people working with strong light sources. Anti-condensation glasses, polarized glasses are new products in the glass market. People have known about polarizers since 1939. However, the technology to produce glasses and consume them is only in the last 20 years. Polarized glasses are considered the best anti-glare. Therefore, it is very suitable for driving, working or playing outdoor sports, fishing, going to the beach. Some special forms are made to work with liquid crystal displays – LCDs, watching 3D movies. Glasses are quite expensive from a few hundred thousand to several million dong a pair.

Insulation film is one of the commonly found equipment on cars today, it is very useful on hot days What is car window film? Automotive insulation film is a type of film composed of many layers of different materials (also known as multi-layer coating) forming a filter plate of spectral ranges. Currently, there are 4 popular insulation film coating technologies, including: Nano Ceramic, Sputted Film, Metalized Coating Film, and Dyed Film. Insulation film gives the user and the vehicle a lot of different benefits The benefits of car window tinting Car window film has the main effect of insulating the outside environment, does not make the environment inside the car warm, stays cool and helps the car interior equipment not be damaged by the sun. heat, ensuring durability and quality when using. According to research, the heat in the sun will be radiated from 3 main sources: 57% from infrared rays, 5% from ultraviolet rays and 38% from visible light. Car window films can eliminate more than 80% – 90% of infrared and ultraviolet rays, but still have transparency, high light transmission, ensuring visibility while driving. The current car insulation films have the ability to insulate up to 50% – 65%. In addition, the film has an effective anti-glare function, while ensuring a clear and effective vision, making you safer and more comfortable. Insulation film helps reduce the temperature in the car, limiting the hot sun nắng The effect of sun protection, temperature reduction One of the most important effects that an insulating film brings to your car is the ability to resist hot sun, reduce temperature and high performance. This will help you always feel comfortable and cool when driving and sitting in the car even when it is hot outside. The film will also ensure no heat leakage, prevent heat from escaping to the outside, and maintain a stable temperature inside the vehicle. Your eyes and skin will also be maximally protected under the effects of the sun Maximum body protection Another equally important effect of insulating film is that it can provide maximum protection for the driver’s eyes and skin in the car. Insulation film has the ability to block most sources of UV rays (the cause of skin damage, potentially causing skin cancer) from 99% or more. This will give your skin maximum protection from darkening, aging and cancer, keeping you safe and comfortable when using a car. The interior of the car will also avoid maximum aging Protect car interior accessories Car window film is effective in protecting accessories and interior equipment in the car to the maximum, avoiding interior aging and fading caused by direct sunlight. damage during use. In the event of a sudden accident that breaks the glass, the shards will not be thrown to hurt the occupants of the vehicle Protect the occupants of the car when the glass is broken Insulation film does not work to prevent car glass from breaking. However, thanks to the insulating film, the glass will not be broken. Instead, the film holds the broken pieces of glass in place so they don’t splash and injure occupants. Sticking black insulation film also helps to ensure privacy inside the car Create privacy For those who want a sense of privacy when sitting inside the car, dark tinted film is the ideal solution. This type of film helps outsiders to not be able to see inside the car while occupants can still see outside.

Tiny bacteria on Earth have bitten these plant remains with specialized enzymes. But because the hungry microorganisms process a large amount of carbon in the soil, even taking in some elements into their cells, the bacteria cannot do the full job, so there are pieces of carbon that are not broken down. dishwashing bacteria. Moreover, they also have carbon in their bodies, so when the bacteria die, the carbon goes back to the ground. It’s a cycle, where there’s always carbon left over. These small pieces accumulate over time. Illustration. Such tiny pieces are the humus material, which accumulates year after year. And bacteria’s carbon storage has given the earth its dirty brown color, because carbon absorbs most of the colors in the solar spectrum, except for the brown light it reflects back. However, not all land on earth is brown. Some deserts seem to have only white sand. The soil in Hawaii, rich in iron, is reddish in color. Dig deep into the ground in some areas that are dirty brown, you’ll see other colors underneath. If there wasn’t too much carbon in the ground, the ground would be yellow, red, and gray. They depend on the color of the dominant mineral there. The Mysteries of the Earth 1. Does anyone know what the structure of the middle layer of the Earth is? According to research by seismologists, we already know that the internal structure of the Earth includes: The inner core is solid. The outer core layer is molten lava. The intermediate layer, called the mantle or mantle, lies at a depth of 30 to 2,900 km. The rock crust can slide away freely. But what the mantle is made of is still a mystery to researchers because we haven’t been able to dig down to this layer or have any evidence of its composition. Until now, the deepest hole that humans can dig is the Kola Drilling Hole in Russia, only 12.3 km deep. 2. Earth’s two poles are interchangeable Scientists have proven that the two magnetic poles of the Earth can change positions and reverse directions. This phenomenon has happened many times in Earth’s history. The last time the Earth changed polarity was 10 million years ago, and it is likely that this will happen again in the future. Until now, scientists did not know how this phenomenon could happen. 3. Earth used to have two moons Scientists confirm that, 4.6 million years ago, Earth had two natural satellites. The second satellite exists in the same orbit as the Moon and has a diameter of about 1,200 km. After a few million years, these two satellites collided. This may explain why the two halves of the Moon are so different today. 4. The Earth actually rotates very fast The Earth, including the atmosphere and everything on the planet’s surface, rotates at a tremendous speed of more than 1,600 km/h, while the Earth’s rotation speed around the Sun is 108,000 km/h. Humans can live and function normally while standing on the ground because we, everything around and the Earth are rotating at the same speed. We can feel this movement thanks to the wind, but since the entire atmosphere is moving at the same speed as us, we don’t feel anything. If the Earth suddenly stopped rotating, we could feel this movement. But it will not be pleasant at all, everything on Earth will be swept away at more than 1,600km/h. 5. Time on Earth is “getting longer” every day 620 million years ago, a day on Earth lasted only about 21.9 hours. But the Earth is spinning more and more slowly, so in the future, our day will be 25 hours long. Scientists have shown that after every century, the Earth’s rotation slows down by about 1.8 milliseconds, which means that a day will be only 2 milliseconds longer. So we have to wait another 200 million years for a day on Earth to have 25 hours. 6. Gravity on Earth is not the same everywhere The Earth is not a perfect sphere, so Earth’s gravity is not uniform, there will be areas of weak gravity and regions of different strong gravity, even places where there is almost no gravity. Hudson Bay in Canada is known as a place of near zero gravity due to the low density of rock here, caused by the rapid melting of glaciers. 7. In primitive times, the Earth used to be purple In ancient times, plants used retinal instead of chlorophyll to absorb light. This substance causes them to reflect red and blue light. This is the reason why ancient plants were red, not green like today’s plants. This led scientists to hypothesize that the original Earth was once purple because it was covered with ancient plants. 8. The ocean hidden in the ground Scientists believe that there is a giant ocean, and the amount of water contained in it is estimated to be three times greater than that of all the oceans on the Earth’s surface. In early 2014, researchers discovered “ringwoodite,” a material located in the transition zone (between 410 km and 660 km deep), as proof that a giant sea of ​​water exists. exist below the surface of the Earth. According to scientists, this underground ocean is about 2.7 million years old, under tremendous pressure.

Choosing for yourself the “true” skincare products for the skin is not easy. Sometimes, in the process of building a list of skincare products, you can completely choose the wrong one. Importantly, women need to identify products that are not suitable for their skin to pause at the right time, to avoid wasting time and effort and causing damage to their skin. The following are signs that you have chosen the wrong skincare product, refer to it now to never make your skin worse! 1. Brown spots appear on the face The ugly brown spots that appear on the skin are mainly caused by prolonged exposure to the sun. But besides that, this is also one of the important proofs that the sunscreen you are using is not effective. That sunscreen bottle may not protect your skin from both UVA and UVB rays, or it’s easy to “cheat” the sun protection index, or the sun protection index is not high enough to protect the skin. When choosing a sunscreen, you should prioritize products from reputable brands, have a broad-spectrum note (broad spectrum, protect against both UVA and UVB rays) and have an SPF of 30 or higher. 2. Skin feels uncomfortable Although some active ingredients, or acne-fighting ingredients like benzoyl oxide can cause some uncomfortable symptoms to the skin such as itching, stinging, and redness, if the condition persists after a few days, day, without improvement, that skincare may not be right for you. If the first time you use a product, your skin feels tight and hot, famous Singapore-based doctor Vanessa Phua warns that your skin may be irritated by some of the product’s ingredients such as fragrances or fragrances. preservative: “Usually you will notice redness and sometimes swelling. In this case, you need to stop using the product immediately, then wash your face with water and then apply a moisturizer to soothe the irritation.” . 3. Acne-prone skin Many people will go through a period of getting used to new products and in the first 2-3 weeks of using the product, your skin will have a few acne spots. However, if acne flares up too much, then the product is not suitable for you. In addition, when shopping for skincare products, you should choose product formulas that are non-comedogenic, or have a light gel texture. 4. Skin secretes too much oil If you find that your skin is producing more oil than usual, you may have used a harsh cleanser; Or an equally common case is applying a product with a texture that is too dense, making the skin sticky and tight. At this point, you need to switch to a gentle cleanser, or stick with a light texture cream that doesn’t contain mineral oil or clog pores so that the skin is still moisturized, but not clogged.

See through smoke and fog, map a person’s blood vessels while monitoring heart rate – without skin contact; look through the silicon wafers to check the quality and composition of the electronic board. Those are some of the many functions of infrared camera new, developed by a team of researchers led by electrical engineers at the University of California San Diego. The camera detects a part of the infrared spectrum known as shortwave infrared light (wavelengths between 1000 and 1400 nanometers), which lies just outside the visible spectrum (400 to 700 nanometers). Shortwave infrared imaging, unlike thermal imaging, detects much longer infrared wavelengths emitted by the body. The camera works by shining short-wave infrared light at an object or area of ​​interest, then converting the reflected low-energy infrared light back to the device into shorter, high-energy wavelengths. than the human eye can see. “It makes invisible light visible,” said Tina Ng, professor of electrical and computer engineering at UC San Diego Jacobs School of Engineering. When technology Infrared imaging has been around for decades, where most systems are expensive, cumbersome, and complex, often requiring a separate camera and monitor. They are also often made with inorganic semiconductors, which are expensive, hard, and contain toxic elements such as arsenic and lead. The infrared camera that Ng’s team has developed overcomes these problems. It combines sensors and display into a slim, compact and simple device. It is made of organic semiconductors, so it is low cost, flexible and safe for use in biomedical applications. It also offers better image resolution than some of its inorganic versions. The camera is made up of multiple layers of semiconductors, each hundreds of nanometers thin, stacked on top of each other. Three of these layers, each made of a different organic polymer, are the key elements of the image: the photodetector layer, the organic light-emitting diode (OLED) display layer, and the blocking layer. electrons in the middle. The photodetector layer absorbs shortwave infrared light (low energy photons) and then generates an electric current. This current flows to the OLED display layer, where it is converted into a visible image (high-energy photons). An intermediate layer, called an electron block, keeps the OLED display layer from losing any current. This is what allows the device to produce clearer images. Another special feature is camera effective in providing optical and electronic indicators. “This makes it multifunctional,” says Li. For example, when the researchers shined infrared light on the back of the subject’s hand, the camera provided an image of the subject’s blood vessels while recording the subject’s heart rate. The researchers also used their infrared camera to see through the fog and a silicon wafer. In one test, they placed an “EXIT” patterned photosphere in a small room filled with smog. In another setting, they placed a photorealist patterned “UCSD” behind a silicon wafer. Infrared light penetrates both smog and silicon, making it possible for the imagineer to see the letters in these illustrations. This would be useful for applications such as helping self-driving cars see in bad weather and checking for silicon faults. The researchers are currently working to improve the performance of this type of camera.

You should choose a sunscreen with an SPF above 30. Sunscreen should have an SPF of 30 or higher – this is a measure of the average number of hours a product has, not how much sunscreen it contains. If the sunscreen index is SPF 30, it means that the index 30 filters 95% of UV rays, if the index is SPF 60, it filters out 97% of UV rays, depending on the skin that has the choice of products. the best. Learn more about sunscreens When buying any product, you also need to learn carefully about it, especially cosmetics are very important otherwise it will adversely affect the skin. Regarding sunscreen, you should choose products that are labeled as non-comedogenic, oil-free and choose sunscreens with the words “broad spectrum” (meaning broad spectrum) to protect you against both skin cancer-causing UVA rays and sunburn-causing UVB rays. Use sunscreen in the right order Because you can use many types of cosmetics or lotions at the same time, you need to know when to use sunscreen is appropriate. If not used in the correct order, sunscreen will not be fully effective, but will also cause more sunburn. It is best to apply sunscreen before applying other products so that it can penetrate the skin and get the most effective sun protection. Always apply sunscreen before going out Sunscreen takes about 15-20 minutes to fully absorb into your skin. So there is a rule you must remember to always apply sunscreen 15-20 minutes before going outside. Choose a sunscreen that blocks UVA rays UVA1 rays in the sun are mentioned as the number 1 “enemy” of the skin. This is the ultraviolet ray with the longest wavelength, penetrating deep into the skin, causing breakage of fiber structure, which is the main cause of dark spots, freckles and wrinkles. Because not all products can block UVA1 rays, choosing to buy a sunscreen that blocks UVA1 rays is the first consideration that needs to be considered. Sun protection even when it’s shady or sitting in the office Have you ever intended to buy a tube of cream to apply only on hot days? If it’s shady or working in the office, why should you use sunscreen? As mentioned above, UVA1 rays are extremely dangerous. The “difficulty” of this type of ray is also mentioned by its ability to penetrate clouds, fabrics or glass doors to affect the skin. They also account for 70% of ultraviolet rays in the sun, so they exist anytime, anywhere. Therefore, regardless of whether it’s sunny or rainy, indoors or out, we need to apply sunscreen every day.

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.

1. Minimalistic skin care: During the day, our skin faces a high risk of clogging pores. In addition to natural oil secretion, the skin is also exposed to dust, bacteria, and toxic substances from the environment. Less use of skincare products helps the skin not overload when it absorbs nutrients. On the other hand, this also reduces pores to minimize clogging. Image: Yooseung_erica. 2. Protect skin with sunscreen: The agent that causes severe skin aging – UVA rays – is present at any time in daylight. A broad spectrum sunscreen with a minimum SPF of 30 is very important. It helps prevent negative effects from UV rays, wrinkles, brown spots or skin cancer. Image: Romi.fit. 3. Choose a low-foaming cleanser: According to the Byrdie , foaming cleansers often have a high pH (high alkaline content). Skin’s natural pH ranges from 4-6. Skin is slightly acidic, and needs to be maintained at a pH in the upper range for best performance. Cleanses with high pH lead to dry skin, increasing oil production after cleansing. Image: Way Of Will. 4. Do not rub the skin with a towel: Many people use a towel to wipe their face in the morning. Some towels carry rough materials that act as exfoliants. Doing this too often will cause skin irritation and irritation. On the other hand, rubbing your face with a towel for a long time leads to the risk of sagging and wrinkling. Image: Martha Stewart, Better Homes and Gardens. 5. Wear long-sleeved clothing: In addition to the skin of the face, neck skin and hand skin are also very in need of care. The skin on the neck and hands is prone to dryness, as well as gradually weakening under the adverse effects of sunlight. Dull skin indicates that the body is working hard to counteract UV damage. In addition to applying moisturizer and sunscreen to your neck and hands, you should also wear long clothes when traveling outdoors. Image: Pinterest. 6. Wear sunglasses and a wide-brimmed hat: A hat shielding hair from the sun. Hair is also susceptible to damage and fraying if it is regularly exposed to the sun. A wide-brimmed hat and sunglasses keep you from squinting during the day. Squinting too much causes premature wrinkles to form around the eyes and between the eyebrows. Image: Thermo Fisher Scientific. 7. Add more water to the body: During the hot season, the body as well as the skin are susceptible to dehydration. Severe dehydration in addition is damaging to your health and skin. Water enhances hydration, thereby reducing excessive oil secretion on the skin. This will limit acne formation. Image: Forbes. 5 easy-to-do anti-aging skin treatments The earlier you fight aging, the longer you will prolong the appearance of these signs of age.

1. Read the label before you buy: First, you need to consider the SPF factor of your favorite sunscreen. According to the FDA , products with a high SPF make people misunderstand that they completely protect the skin from sunburn and long-term damage. This false feeling makes people confidently that more direct sun exposure leads to aging and skin pigmentation cancer. Image: Style. 2. Check the SPF: “Sunscreen’s SPF 30 will block 97% of the harmful rays from the sun,” said dermatologist Seth Forman from the Institute of Dermatology and Skin Cancer. At the same time, you must pay attention to the PA rating – the more marks + the higher the skin protection. Try to buy a sunscreen that has at least PA +++ protection. Because both SPF and PA work in parallel to protect the skin, preventing sunburn as well as damage from penetrating deeply inside the body. Image: parade. 3. Water resistance: “Water-resistant sunscreens are great for hot days or when playing sports,” says Dr. Forman. “However, these products are sticky and need to be reapplied every 2 hours.” Besides, the sunscreen only remains effective under water for 40-80 minutes. Therefore, you must reapply regularly for best results. Image: freepik. 4. Avoid allergens: Our skin becomes more sensitive each summer comes. Choose products that have no preservatives, strong scents, and the ingredients PABA or oxybenzone. People with allergies and reddened skin conditions should avoid alcohol-based formulations. On the other hand, if your skin has acne, you need to limit greasy, long-lasting creams. Instead, it’s a gel formula, which quickly penetrates the skin. Image: Forbes. 5. Broad spectrum search: SPF is important, but make sure your sunscreen says “Broad Spectrum” to protect against both UVA and UVB rays. UVA rays penetrate the skin deeper causing wrinkles and brown spots. On the other hand, UVB rays cause skin redness, burning and damage to the outer layers, even skin cancer. Image: leisure pro. 6. Consider skin type: Many sunscreens are tailored to each skin type. People with dry skin should look for glycerin, lanolin, oils and silicone-based ingredients. Avoid alcohol-based sprays or gels. Oily skin should look for gentle options like gels with a silica or isododecane component. People with sensitive skin need to invest in a hypoallergenic and fragrance-free sunscreen with a choice of minerals with titanium dioxide or zinc oxide. Image: scmp. 9 easy to forget places when applying sunscreen Some small areas of skin such as the ears, between the fingers … are often not paid attention by people when applying sunscreen.