It creates an infinitely curved region of space-time, from which nothing can escape, not even light. Do black holes rotate? This is an interesting but not so simple question that I received in one of my recent lectures. To answer it completely and accurately, we need a clear understanding of the very verifiable properties of black holes as well as about the nature of rotation. To date, the concept of rotating black holes is not new. In fact, every object in the universe, once having a mass large enough to be spherical, will also have a rotation. Since mass exerts gravity, every object tends to compress itself – because its parts attract each other. For small masses, this gravitational compressive force – commonly known as centripetal gravity – is so small that it cannot exert any effect on the object, because it is simply an intermolecular force of cohesion. substance – especially solids – is much larger than it is. But with very large masses, on the other hand, the force of gravity is so great that matter will rearrange until it becomes spherical. That is, the state in which the force of gravity directed at the center of the object from all directions is equal to each other. That’s how every object as large as a planet or a star gets its spherical shape. At the same time, when there is such a large mass, another problem arises, and also related to gravity. Since no single star or planet is perfectly uniform, in fact the gravitational forces in their different regions are unequal. This difference is the main reason they oscillate, and hence the rotation. Thus, all large objects in the universe rotate because of their own gravity. What about black holes? The most common types of black holes known to scientists today are stellar-mass black holes. It is formed from the late-life contraction of the cores of massive stars. These stars are usually at least 8 to 10 times the mass of the Sun. Towards the end of their lives, their cores shrink very rapidly because the fusion reaction no longer produces enough energy to resist the contraction of that enormous mass. This sudden contraction causes an explosion that is considered one of the most violent events in the universe” supernova explosion. This explosion tore apart the stellar shell that was previously in the state of a red supergiant. The remaining core of the star shrinks and collapses to become a black hole. All stars rotate on their own axis (our Sun, for example, has a rotation period of more than 25 days). It is not difficult to speculate that something formed from a rotating stellar core would also have to rotate, because that momentum is simply still there. The same is probably true of supermassive black holes – black holes with masses ranging from hundreds of thousands to billions of times the Sun, located at the center of most galaxies ever observed. In fact, when the first image of a black hole was released in 2019, scientists were able to see the spirals of the accretion disk surrounding the black hole. It shows that the giant accretion disk is rotating, not fixed. Just like the fact that all the stars in each galaxy are constantly moving around the center of the galaxy (for example, our Sun takes about 230 million years to complete one full circle around the center of the Milky Way). Two things need to be clarified before concluding that the black hole rotates on its own The entire initial mass of the black hole – in theory – is packed into an extremely small singularity. It is so small that it can mathematically be considered sizeless. That singularity has a certain radius (Schwarzchild radius) known as the black hole’s event horizon, but it is just a region of pure space-time, not an object like it has a surface. like a star or a planet. As such, it is difficult to consider something with no dimensions, or a boundary without a surface, to be rotating, since there is simply no alternate motion of points to a particular surface. No radiation comes out from within the event horizon, which also means that all information inside a black hole is unknown. If matter were indeed crushed and completely collapsed into a single point, the space within the event horizon could itself be a place of absolute uniformity, i.e. no rotation would occur due to the difference. interesting. With these two points in mind, don’t forget that what we see spinning is itself just the accretion disk surrounding the black hole. Of course, one can also calculate the rotational speed of an accretion disk based on its mass when taking into account as well as when not taking into account the presence of a black hole at the center, from which to compare and predict. It looks like the black holes in those places are spinning very fast. Even so, given that we don’t know anything about what lies within the event horizon, or even something specific happening at its very edge, concluding that black holes are indeed rotate or not and how fast they rotate is still too early. Likewise, the charge of a black hole is also a purely theoretical concept and is calculated from solving Einstein’s equations. There is no way for us to verify if an electric charge really exists after being swept inside the black hole’s event horizon. In the future, to know more about this information, we will need to look forward to new generations of telescopes and new methods to image and track more black holes with much greater detail. compared to what there are today.

But many Covid-19 tests can give results within hours without sending the sample to a lab, and most of these tests use an approach called microfluidics. What are microfluidics? A microfluidics system is any device that handles small amounts of liquid. Fluid moves through channels thinner than a hair, and tiny valves can turn the flow on and off. These channels are made of materials such as glass, polymers, paper or gel. One of the ways to move liquids is to use a mechanical pump; another way is to use the surface charge of certain materials; and one more way is to use so called capillary action – commonly known as wick. One thing is clear, every nook and cranny of the human body is microfluidic. We could not be born or function without complex blood capillaries that carry food, oxygen, and signaling molecules to every cell. Like microelectronics, size is a key factor in microfluids. As components get smaller, devices can rely on the exotic properties of liquids on a small scale, can work faster, more efficiently, and have cheaper manufacturing costs. The microfluidics revolution has been quietly shouldering microelectronics technology. Another major benefit of microfluidic devices is that they require only a very small amount of liquid and can therefore be very small in size. NASA has been considering using microfluidic analyzers for their long Mars missions. The analysis of precious liquids – such as human blood – also benefits from the ability to use small samples. Example: A glucose meter is a super liquid instrument that requires only one drop of blood to measure a diabetic’s blood sugar. Chances are you have been using microfluidics quite often in your life. Inkjet printers shoot out tiny droplets of ink. The 3D printer extrudes the molten polymer through a microfluidic nozzle. A nebulizer for asthma patients will spray out tiny droplets of medicine. The pregnancy test relies on the flow of urine in a microfluidic strip of paper. In scientific research, microfluids can direct drugs, nutrients or any liquid to very specific parts of an organism to more accurately simulate biological processes. The future of microfluidics Microfluidics will be key to bringing medicine into a new, fast-paced, affordable era. Wearables that measure substances in sweat to track fitness progress and implantable devices that help deliver cancer drugs locally to a patient’s tumor are some of the next frontiers in microbiology. biomedical liquid. Researchers are developing complex, fascinating microfluidic systems called organs on a chip that aim to simulate different aspects of human physiology. In laboratories around the world, teams are developing tumor-on-chip platforms to test more effective cancer drugs. These patient-representative chips will allow scientists to test new treatments in a way that doesn’t entail the cost, suffering, and ethical issues associated with animal or human testing. Imagine going to the doctor, taking a biopsy sample and, in less than a week, using the scientists’ microfluidic device, the doctor can figure out which drug is most effective to remove the mass. your u. While that is still in the future, what we do know is that microfluidic will be an integral part of the future.

Wireless electricity does not emit radiation. This picture seems impossible at first glance but is being realized gradually through an idea called “wireless electricity”. From the Tesla coil From 2021, Powerco, New Zealand’s second largest electricity distributor, will work with start-up Emrod to bring wireless electrical technology to life. It all stems from the ambitious dream of the Serbian engineer, Nikola Tesla. Back in 1899, in the city of Colorado Srpings, USA, Nikola Tesla created a 50m high coil with a current of 12 million volts, called the “Tesla coil”. The coil has an activation switch. Just flip the switch, a flash will flash from the coil, carrying wireless current to light up 200 nearby bulbs. During the test, no one was injured. This experiment hypothesizes that the Earth can conduct electricity by itself without the need for a transmission device. And the technology of transmitting electricity in the air can be quite safe for humans or other living things. After that, Nikola Tesla continued to experiment with electromagnetic induction, discovered by scientist Michael Faraday from the 1820s. According to this experiment, around the electromagnet has a changing magnetic field, creating an electric current in a wire is nearby. Electric currents in a wire create electrical energy in the air, which can exist as a magnetic field. From his experiments, he modified and perfected the Tesla coil, the first system to wirelessly transmit electricity. The Tesla coil consists of two parts: a primary coil and a secondary coil. Each coil carries its own capacitor. The two coils and capacitors are connected by an ignition slot and can produce a spark. In general, the Tesla coil is two open circuits connected to an ignition slot. It needs a source of high voltage messages, passed through a transformer to produce thousands of volts. First, the primary coil will be connected to a power source. It will absorb electrical charges like a absorbent sponge. The primary coil is usually made of copper, a material that conducts electricity well, as it must be able to withstand very large charges and many electric waves. When the primary coil’s capacitor has accumulated a lot of charge, it will escape and create a magnetic field. Magnetic energy induces an electric current in the secondary coil. The compressed voltage through the air between the two coils creates a spark in the air. When the charged charge in the capacitor of the secondary coil rises, it will escape in the form of an electric arc. When this happens, an energy is enveloped between the two coils. The high frequency voltage can light fluorescent bulbs a few feet away without the need for a transmitter. Wireless power network infrastructure Inspired by Nikola Tesla’s invention, New Zealand-based Greg Kushnir founded the Emrod Energy Company. The company plans to deploy wireless power infrastructure. To do this, Emrod uses a system consisting of a power source, a special antenna capable of converting radio waves into electricity, called “rectenna,” the base stations. The transmitting antenna converts electricity into microwave particles. In the area using wireless electricity, Emrod installs base stations fitted with square pads. The microwave particles transmitted to the receiver will be gathered into a beam, leading to the rectenna in the area. The rectenna’s job is to convert the microwaves back into electricity. The reason that the receiver is square is because it needs a large surface area, which helps to collect all microwaves passing through. “We have developed a long-range wireless transmission technology,” said Greg Kushimir. The technology itself has been around for a while. Our project is a continuation of Tesla’s achievements ”. However, Kushimir commented that Tesla can generate alternating current from the Tesla coil but he cannot control the electric beam at a long distance. In contrast, Emrod can keep the electric beams tightly connected, stable transmission thanks to two technologies. First, it must be mentioned is the technology related to transmission lines. The microwaves passing through the collimator are converted into a parallel beam of light. Next, Emrod used metamaterials designed in microscopic samples, highly efficient in microwave reception. The Rectenna acts like an invisible cable. Their job is to transmit electricity to the people. By eliminating the traditional wiring, Emrod can bring electricity to areas with difficult terrain, difficult to access because the infrastructure here does not support electricity networks. This technology also has a positive impact on the environment as people do not have to depend on generators that run on gasoline or oil. Power generation stations can also be quickly installed after a natural disaster. Thus, bad weather does not affect the wireless power transmission system. However, Kushimir expressed the challenge now is communication and public orientation. Like the advent of 5G, many people may oppose this idea due to concerns about the negative effects of radiation. But Kushimir asserted, the wave beam transmitted in the new technology does not emit radiation harmful to humans.

You have probably experienced cases of cooking oil splattering when you fry it with food. The reason is that your food is too watery. The temperature difference between the water and the boiling oil causes the oil to splash out. Therefore, you need to drain the food before frying.

When placing food in the pan, be very gentle and careful to avoid boiling the oil on yourself.

Select the pan used for frying

To limit the oil splashes out during the frying process, use high-walled, deep-walled pans with moderate surface charge. This will help reduce the oil splashes and save on cooking oil if you need to deep-fry the food.

Illustration.

Add salt to the oil pan

Putting a few grains of salt in the saucepan of boiling oil will help prevent the oil from spattering.

In addition, placing the anise petals in the pan also helps to limit the oil splashes and gives the dish an attractive scent.

Use lemons

Take a slice of lemon and rub it all over the pan before adding the grease. This will help reduce grease spatter during cooking.

Use ginger

Place the pan on the stove and light. Wait for the pan to heat and use chopsticks to gently press while rubbing the slice of ginger all over the bottom of the pan. Do this for about 2 minutes and remove the ginger slice. Continue adding oil and frying as usual.

Preheat pan before adding oil

Make sure your pan is heated and free from water before adding the oil. This prevents the oil from splashing out when cooking and the food never gets close to the pan.

Use screens

Buy an oil screen that matches the size of the pan. They will prevent the oil from splattering out during frying and won’t get the food wet like the lid on the pot.