The researchers found that from their first flight, these echolocating mammals somehow knew exactly how long it would take for the sound waves of their calls to echo from their prey. again. An innate reference point related to the speed of sound allows bats to judge distance in units of time, as opposed to spatial units like humans. Unlike humans who rely heavily on sight, various types of bats “see” the world around them with their ears. However, just as our eyes can fool ourselves, bats don’t always decode their echoes correctly. Illustration. For the test, the team housed six newborn bats in normal atmospheric conditions, as well as five newborn bats in helium-enriched air. This will increase the speed of the sound. These two groups were then tested for echolocation in their respective environments. When approaching a food target, helium-enriched airborne bats displayed echolocation patterns and normal airborne bat-like flight behavior. When a bat flies and lands somewhere, it requires precise coordination between its call to attract and its body. As the creature gets closer to its target, the bat’s echolocation speed increases, and when landing slows, it rolls its body, straightening its legs. However, in an environment where the speed of sound travels faster, this all happens much faster, causing the bats to land ahead of their target. Despite many attempts, the bats still managed to approach the target using the normal sound reference speed. The problem is that bats never learn from their mistakes. Even when adult bats were conditioned in a helium-enriched environment for several days, the researchers found that they were unable to change this fixed reference point. This is surprising, since sensory learning is an advantage for many animals, especially those with the ability to change conditions. Little known secrets about bats According to the analysis results of scientists, in the feces of bats there is a lot of potassium nitrate salt, also known as salt pepper. This chemical is the main ingredient in many fertilizers. At the same time, it is also used to make explosives and detonators. In the past, especially during the American Civil War, bat droppings were considered an important resource for both sides. Because from this waste, one can extract salt and pepper (which is quite scarce) to supply the army. When it comes to bats, most of us probably think of animals with a “unique” way of sleeping upside down. According to scientists, this unusual sleeping position of bats actually has its own purpose. Specifically, unlike birds or insects, the leathery wings of bats are not strong enough to easily lift them from the ground to the air. Therefore, when resting, bats always choose an elevated position so that when they need to fly, they just drop down, taking advantage of air resistance to support take-off. However, according to statistics, there are 6 species of bats that do not hang upside down when sleeping. Most of them have suckers on their limbs, allowing them to cling to leaves or other flat surfaces to sleep. In fact, only small bats (suborder Microchiroptera) have poor eyesight and must be located using sonar. Meanwhile, the larger representatives (of the suborder Megachiroptera) possess excellent eyesight. Even the vision of these bats is better than that of humans. However, in exchange for “bright” eyes, members of the suborder Megachiroptera do not know how to use ultrasound waves.

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.

As of mid-December 2020, Forbes It is estimated that the net worth of the group of more than 2,200 billionaires in the world has increased by more than $1.9 trillion. Many of these people are spending a large part of their money on personal pleasures, according to NZ Herald . Recently, Jeff Bezos, the owner of Amazon, bought a yacht so large that it needed a “side boat” to support. The total estimated value of this yacht is up to 500 million USD. That figure is just a fraction of the more than $75 billion in earnings Bezos made last year. The super-rich are “crazy” to buy probes and cruisers. Photo: NZ Herald. Over the past year, superyacht maker Cecil Wright & Partners has sold 354 units, costing $840 million to build. Due to travel restrictions between countries, many have been acquired. The super-rich are also eyeing the Arksen marine exploration ship and luxury cruiser. At around $17 million, they allow owners to explore the wildest places on the planet. “The elite want to know how far they can go when it comes to unexpected adventures,” says Jasper Smith, president of Arksen. Longing to travel Helicopters and electric cars are also favored by Ultra-High Net-Worth Individual (UHNWIs) individuals. They hope to make the most of them once the Covid-19 pandemic is over. “Three times in lockdown and spending most of my time at home has made me hungry to travel and experience,” said Martin Reith, president of Luchford, the media agency for luxury brands. In addition, the super-rich also want to find private resorts. For example, Lopud 1483 in Croatia, a renovated monastery with a rental price of 137,000 USD/week, or Deplar Farm, which offers high-speed heli-skiing and luxury trout fishing in Northern Iceland. Private planes and helicopters are loved by the elite. Photo: Insider. Many other rich people are also interested in electric cars. They love buying a Polestar 2 and riding around the city on Porsche’s new e-bike. Meanwhile, helicopters are more popular than ever in the UK. “Bamfords helicopters are a regular occurrence at the Daylesford Shire. I saw them hovering more and more over the Cotswolds. They come in handy for commuting to London. Owners can go anywhere in minutes,” said Harry Gladwin (from the UK). For others, hunting for land and houses is a prerequisite. Jess Simpson, a real estate agent over $20 million, receives three calls a day. Simpson said his clients are always worried there won’t be enough room for nannies, tutors and grandparents should the government blockade again in the future. “Bahamas is a good choice because of the good tax rates. In Europe, the South of France and the Balearics are attracting great interest. Some have moved to Ibiza permanently to send their children to private schools and enjoy life. Also, Portugal is also very popular, because buying a house there can guarantee EU citizenship,” Simpson said. Currently, the richest people in the UK are focusing on buying more houses. Their obsession with space has brought them to Scotland, where there are sports grounds and castles to relax with friends and family. Real estate investment Beach homes are also selling at a rate not seen since 2007. Many are looking for apartments in Norfolk, Dorset and Cornwall. “Private vineyards are gaining in popularity. Many have even established oak plantations,” adds Simpson. While the middle class is fleeing the capital to find a place to live, the super-rich still see London as “true love”. Others are investing in art and furniture. Baird Allis (40 years old), a lawyer, feels happy to own paintings of the Dutch golden age. Modern swimming pools are favored by the rich. Photo: New York Times. In addition, the upper class also splashed money on basements to create multifunctional spaces for working, relaxing, exercising, eating and playing. “Customers often want a meditation room, a ‘vitamin C shower’, a giant changing room, a golf simulator, and a tennis player in their own home,” said Edoardo Alessandro Mapelli Mozzi (UK), real estate developer. real estate, say. After a year without parties, socializing activities are also a priority for individuals with extremely high net worth. It’s no surprise that London’s most exclusive restaurants cater to only 10 pre-booked diners each evening. According to expert Katrina Kutchinsky, the trend of home restaurant-style dining continues to explode. It is normal for the super-rich to invite famous chefs like Alex Webb, the MasterChef champion, to prepare dinner by the pool. Natural swimming pools are equally popular. The list of works of many furniture companies has stretched to 2022. This leaves the super-rich customers with no choice but to endure a summer of “no” new-style swimming pools.