Category Archives: Physics

How Many Multiverses Are There? | Cosmology | Documentary

How many multiverses are there? The universe we can observe is not unique, but there are billions of others. In other words, the universe would be part of a larger “multiverse.” As a result, some well-known scientists have spoken of a super-Copernican revolution. According to this idea, not only is the Earth just one planet among many, but the universe itself is insignificant on a cosmic scale, one among countless other universes governed by their own laws.

Video: How Many Multiverses Are There

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The term multiverse has several meanings. We can explore the space surrounding us to a distance of about 42 billion light-years, which is the distance light has traveled since the Big Bang if cosmic expansion is taken into account.

However, there is no reason to assume that the universe ends at this cosmological horizon. It could continue indefinitely beyond that, through a succession of zones similar to our observable region. The distribution of matter would differ from one region to the next, but the physical laws would be identical.

Almost all cosmologists accept this multiverse view as a collection of similar regions. Max Tegmark, a cosmologist from Sweden, has called it a “level 1 multiverse.”

An infinity of different universes

Some go even further. They imagine an infinity of different universes, subject to different physical laws, with different histories, and even spaces that do not have the same number of dimensions. Most would be barren, but some would be teeming with life. One of the main proponents of this “Stage 2” multiverse is the Russian cosmologist Alexander Vilenkin, who paints a dramatic picture of an infinite set of universes containing an infinite number of galaxies, an infinite number of planets, and an infinite number of people who are your doubles reading this article.

Such representations are not new and are found in many cultures throughout history. What is new is the idea that the multiverse is a scientific theory, with all that implies in terms of logical rigor and confrontation with experience. This idea makes me skeptical. I do not believe that the existence of these other universes has been or can ever be proven. In my opinion, the proponents of the multiverse not only expand our understanding of physical reality but implicitly redefine what is meant by “science”.

Proponents of the stage 2 multiverse hypothesis have no shortage of ideas to explain or highlight this proliferation of universes. These universes could, for example, be in very distant regions of space that have not expanded at the same rate as ours, as predicted by the perpetual inflation model of Alan Guth, Andrei Linda, and others. These universes could have existed before ours, as suggested by the cyclic model of Paul Steinhardt and Neil Turok. Or they could exist in parallel, as other realizations of the quantum states of the universe, as David Deutsch and Michael Lockwood argue. These universes could also be completely decoupled from our spacetime, as suggested by Mr. Tegmark and Dennis Sciama.

Two Scientists Are Building a Real Star Trek Impulse Engine | Impulse Space Propulsion

Real Star Trek Impulse Engine: Using conventional fuel rockets, it would take 16,000 years to reach the nearest star. Interstellar travel cannot be achieved with conventional rockets. While space may be the final frontier, rocket fuel won’t get us very far. The “impulse engine” from Star Trek might one day become a reality thanks to two scientists who are working on a device.

Video: Impulse Space Propulsion – Two Scientists Are Building a Real Star Trek Impulse Engine. Made By Bloomberg Quicktake, 2022. Nasa scientists Dr. Hal Fearn and Dr. Jim Woodward are attempting to build an “impulse engine”.

How does the Star Trek impulse engine work?

The impulse engine is a fictional type of thruster in the Star Trek universe. It is used by shuttles and spaceships for limited movement or in situations where more powerful warp engines cannot be used or are not available.

As with rocket engines today, the impulse engines of Star Trek are based on Newton’s third law (for every action there is an equally powerful and opposite reaction).

Main Components

There is an impulse reaction chamber, a generator/accelerator, a vectored exhaust jet director, and a motor coil assembly in each engine. In addition to the impulse engine, a fusion space-time compaction motor coil is required to accelerate larger starships. It wouldn’t work with just a Newtonian reaction motor.

Operation

In the pulse reaction chamber (a sphere with a diameter of 6 meters), deuterium is introduced and a standard fusion reaction occurs. Following a velocity increase, the plasma passes from the pulse reaction chamber into the drive coil assembly. Through the vectorized exhaust jet controller, exhaust gas is ejected from the drive coil assembly. Through this, the impulse engines can be controlled in which direction to propel the ship.

Description

The impulse drive consists of three main components: a fuel tank, a nuclear reactor, and a space-time coil. The fuel tank contains the reagents used by the engine. Starfleet uses Deuterium as fuel. Although it is less efficient than a mixture of Deuterium and Tritium, it is easier to produce. Especially if using only one type of fuel, there is no need to build additional tanks for the other type of fuel.

After the fuel leaves the tank, it undergoes cooling. During this process, the Deuterium turns into ice balls of varying diameters. These balls are sent to the reactor, where the nuclear reaction begins and continues as long as the fuel is in the reactor. The deuterium atoms join together. In the process, part of the fuel is converted into energy. The maximum efficiency of such an engine is 0.08533%. The efficiency may be different for different types of pulse engines.

The GALAXY class starships use the standard impulse engine reactor. It is a sphere with a diameter of 6 meters. A pulse engine typically uses multiple reactors that transfer energy and fuel to each other in a chain. Each of the eight impulse engines of a GALAXY-class starship has three nuclear reactors.


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What Is the Future of the Universe?

In the past, it was assumed that the universe would expand to a maximum in the future and then retreat again with the same gravity. However, the latest research, studies, and theories say that not only does it not stop expanding, but it actually expands faster and faster, so that the final goal seems to be total entropy.

What will happen when this maximum entropy is reached? Many thousands of years will pass. The future of the cosmos will probably be very different from what we know today. If we look at our closest zone of influence, the Sun will die in about 5000 years, after becoming a red giant, going supernova, and becoming a black hole or neutron star. At that time, the Earth will have long ceased to exist, having previously become a barren, burned-out planet.

Later, our galaxy, the Milky Way, will collide with the neighboring Andromeda Galaxy, which is also in the galactic neighborhood known as the Local Group. Many millions of years remain, but the effects will be brutal and are inevitable.

Future of the Universe

Although before that, if people on Earth are still here in a few thousand years, they will be able to see the star Betelgeuse explode. This red giant in the constellation Orion is very massive and is about to go supernova.

If we humans are still on Earth in 250 million years, we will have to say goodbye to the Moon. The moon moves a little further away from our planet every year until it can no longer exert enough gravitational pull on it to stay by our side.

Our journey takes us billions of years into the future, at the end of time. Then, we will be able to learn what the next step might be for our planet and our universe.

More details about the possible the universe’s future

There are many other possibilities that scientists are working on. For example, it could be that the outer planets of the solar system change their orbits into irregular paths so that Jupiter could approach the Sun and destroy everything in its path.

There is also the possibility of the Earth’s core cooling, a phenomenon that is already a reality. There are many years ahead, but that seems to be the future of this rocky planet, as well as many others.

And, as a final hypothesis, before the universe reaches full entropy and the stars and galaxies are far apart, it could be that the expansion caused by dark energy becomes so strong and powerful that it destroys the entire universe because it is unable to withstand so much force. Will this be the moment when a big bang occurs and a new universe is created?


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Was The Universe Born From Nothing?

The universe was born from nothing? At the beginning of everything, there was no matter and it appeared as a consequence of the evolution of the cosmos. Something we are still trying to understand.

Even though matter didn’t always exist in the universe, it must have been created very early on. I’m amazed by this, so naturally, my first question is: Where did it come from? What was the process? We are not talking about anything philosophical or religious, but simply about pure physics.


Video: Was The Universe Born From Nothing?

To try to understand this we must focus on one of the most surprising discoveries of modern cosmology: the acceleration of the expansion of the universe. To try to understand this we must focus on one of the most surprising discoveries of modern cosmology: the acceleration of the expansion of the universe. The projection of this result is that the expansion is forever and with a uniform velocity. But for this to happen, a critical density is necessary. This is the density that the universe must-have for the expansion to be effectively uniform and with constant velocity, which is currently about 14 hydrogen atoms per cubic meter.

Therefore, we must consider the following relationship: if the energy density in the universe is just enough for it to expand at a constant velocity, then the energy associated with that motion is equal to the energy associated with the distances between particles. In other words, the kinetic energy is equal to the potential energy. Now, since the energy of a material system is the sum of these two energies, then the total energy must be exactly zero. In other words, “the universe is born from nothing.” Amazing, isn’t it?

This result is not only one of the solutions of Einstein’s equations but also the one preferred by theoretical and observational astrophysicists. This is because all observational and theoretical evidence points in that direction.

The universe was born from nothing

This result is not only one of the solutions of Einstein’s equations but also the one preferred by theoretical and observational astrophysicists. This is because all observational and theoretical evidence points in that direction.

If we now go into detail, there are three possible solutions to Einstein’s equations. The first option says that if the density of the universe is greater than the critical density, everything would (eventually) collapse into a black hole and we would decay into elementary particles. The second says that if the density is less than the critical density, everything would move away from everything and we would no longer see stars and galaxies in the sky, i.e. darkness. The third – the most popular at present – says that the universe has a critical density and total energy of zero. Don’t you find it incredible that the total energy of the universe is zero and here we are?

Much of the astrophysical activity of the last 20 years has focused on testing all of these points. All kinds of experiments and observations have been developed, huge telescopes and extremely sophisticated instruments have been built to measure the density of the universe. Very sophisticated methods have even been used; some use the kinematics or motion of galaxies, others the properties of background radiation or the remnant of the Big Bang, others large-scale structure, etc. All of these results agree that the density of the universe is the critical density, which means that the total energy of the universe is zero. This is not trivial to accept!


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Gravitational Force Definition

What is Gravity? Gravitational force is the force that large bodies, such as planets, exert on smaller objects. Gravitational force attracts objects thrown toward the Earth and also keeps the Moon in its orbit. The term Gravitational force is used to describe this force, which has a number of implications for air and space travel. Sir Isaac Newton developed the Universal Law of Gravity, with which he created an equation that can be used to find out about the gravitational force of celestial bodies.


Gravitational Force Definition

1. Gravity

Gravity is one of the basic forces that everyone is used to; For most of us, gravity is an almost unnoticed part of everyday life. Our earth’s gravitational force causes an object to return or be thrown and fall to the ground. In addition, many of Earth’s man-made and natural satellites are held in orbit by gravity. Sir Isaac Newton is credited with discovering a method of calculating gravity based on a number of factors including the size and mass of a celestial body.

2. Law of Universal Gravitation

The law of universal gravitation is used to determine the energy of the gravitational force exerted by a planet or a star. The equation takes into account the masses of the two objects under study, the distance between them, the gravitational force, and the universal gravitational constant. This equation was used by Newton to postulate that an object moves around the Earth at the proper speed to constantly orbit the planet. The Global Positioning System (GPS) and other man-made satellites rely on Newton’s discovery in their design.

3. Solar System

The solar system exists because of the gravitational pull of a star. Dust, dirt, and other objects in space are pulled into orbit around the star and form planets through collisions. Earth was formed about 4.5 billion years ago by the gravitational pull of the star at the center of the solar system, the Sun. The Sun supports all the planets that orbit it by the same principles that cause the Moon to orbit the Earth.

4. Considerations

Space missions rely on knowledge of gravity to successfully launch things like Voyager 1 and Voyager 2. Telescopes, satellites, space stations, missions, and all other extraterrestrial activities take into account the gravity exerted by Earth and other planets when planning missions. This is because the gravity of a planet could throw a spacecraft off course. In addition, Earth’s gravity is the most critical factor in the design and construction of the craft.

5. Impact

Newton’s law of universal gravitation played a central role in the development and understanding of Einstein’s theory of relativity. According to Professor Bangalore Sathyaprakash of the School of Physics and Astronomy at Cardiff University, the theory of relativity had to be modified due to conflicts between the statements of the law of universal gravitation and the way Einstein had established the theory of relativity. The idea of general relativity came about as a result of these conflicting ideas.


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What is Radiation

What is radiation? Radiation is various types of energy in the form of particles or electromagnetic waves that travel through space. The radiation has different compositions and origins.

Radiation is a physical process of emission (output) and propagation (displacement) of energy by moving particles or electromagnetic waves. This process can occur in a material medium or in space (vacuum).

The following are examples of well known and commented upon radiations:

  • Alpha
  • Beta
  • Gamma
  • X-rays
  • Ultraviolet
  • Visible light
  • Radio waves
  • Infrared
  • Microwaves, etc

Classification of radiation

According to their origin, radiations are classified as natural or artificial.

Natural

These are radiations that originate from a source not generated by human technology and occur spontaneously. An example is nuclear radiation, which emanates from inside the atomic nucleus of a chemical element.

Naturally radiating elements are found, for example, in rocks or sediments. Another example of natural radiation is cosmic radiation:

  • Protons
  • Electrons
  • Neutrons
  • Mesons
  • Neutrinos
  • Atomic nuclei
  • Gamma rays, which comes from solar and stellar events

Artificial

These are radiations produced by electrical devices in which particles, e.g. electrons, are accelerated. This is the case with X-ray tubes used in radiodiagnosis.

There are also radiations produced by non-electrical devices, i.e. chemical elements irradiated by the acceleration of particles.

Nuclear

These are radiations coming from inside the nucleus of an unstable atom. The nucleus is unstable if the atom has 84 or more protons in it on average. There are only three nuclear radiations: Alpha (α), Beta (β) and Gamma (γ).

Types of radiation

Depending on their ability to interact with matter, radiations are classified as ionizing, non-ionizing and electromagnetic.

Ionizing

These are radiations that, upon contact with atoms, promote the escape of electrons from their orbits and transform the atom into a cation, i.e., an electron-deficient atom.

These radiations can cause ionization and excitation of atoms and molecules, changing the structure of the molecules (at least temporarily). The most important damage is that which occurs in DNA.

The most important examples of ionizing radiation include:

  • Alpha radiation: it consists of two protons and two neutrons and has low penetrating power.
  • Beta radiation: It consists of one electron and has a higher penetrating power than alpha, gamma and X-rays.
  • Gamma radiation and X-rays are electromagnetic radiations that differ only in their origin (gamma radiation is nuclear and X-rays are artificial) and have a high penetrating power.

Non-ionizing

These are radiations that are unable to remove electrons from the orbitals (electrospheres) of their atoms. Thus, they remain stable atoms. These radiations cannot cause ionization and excitation of atoms and molecules. Thus, they do not cause any (at least temporary) change in the molecular structure. Among the most important examples of this type of radiation are:

  • Infrared: radiation that is below red in the energy diagram and has a wavelength between 700 nm and 50000 nm.
  • Microwaves: are radiations produced by electronic systems through oscillators and have a higher frequency than radio waves. They are used in home to heat food and can transmit television signals or electronic communications.
  • visible light: has a frequency between 4.6 x 1014 Hz and 6.7 x 1014 Hz, with a wavelength of 450 nm to 700 nm. It is capable of sensitizing our vision.
  • Ultraviolet: radiation emitted by some atoms when they are excited, associated with the emission of light. It has a wavelength between 10 nm and 700 nm. Example: mercury vapor lamps (Hg).
  • Radio waves: are low frequency radiations, about 108 Hz, with a wavelength from 1 cm to 10000 nm. They are used for radio transmissions.

Electromagnetic

These are waves with a magnetic field and an electric field that propagate in air or in vacuum at a speed of 300,000 km/s. These radiations (gamma radiation, X-rays, ultraviolet, infrared, microwaves) are distinguished according to their wavelengths, as can be seen in the figure of the electromagnetic spectrum below:

Image of the Electromagnetic spectrum radiation.
The Electromagnetic Spectrum. What is Radiation.

Radiation Risks

Animals, plants, soil, water, and air can all be affected by radiation, each in their own way. In fact, soil, water, and air, when contaminated by radioactive substances, become carriers of radiation that is transmitted to living things.

In living things, radiation has two main effects:

  1. Genetic mutations: Exposure to radiation can alter the DNA of the cell so that a cell loses its function or performs a new function. Example: Genetic mutations can lead to the formation of new tissue, or cause a cell to perform a new function, leading to the development of a tumor.
  2. DNA breaks: Radiation can break DNA molecules and hinder the process of cell reproduction. This process can mean that cells are unable to pass on their genetic inheritance as they multiply. Cell function may be impaired, but it does not have to be.
Radiation Changes Your DNA.
Radiation Changes Your DNA.

It is worth noting that the extent of damage caused by radiation depends on two very important factors: the dose (amount of radiation that the body received) and the exposure time.

Short-term side effects

  • Nausea
  • Vomiting
  • Diarrhea
  • Fever
  • Headache
  • Burns
  • Alteration in blood production
  • Platelet breakdown
  • Decrease in immune resistance

Long-term damage

  • Skin, lung and other cancers
  • Presence of radiation in the entire food chain
  • Decreased fertility

Utilization of radiation

Regardless of the type (ionizing or non-ionizing) and origin (nuclear or non-nuclear), radiation has various uses. Among them we can highlight:

  • Sterilization of surgical material (medical or dental);
  • Sterilization of industrial food;

Note: Sterilization is performed to kill microorganisms such as fungi and bacteria.

  • Use in radiotherapy (alternative cancer treatment);
  • Medical imaging examinations (mammography, radiography and computed tomography);
  • Use in quality control in the manufacture of metal parts, mainly for aircraft;
  • Dating of fossils and historical artifacts using carbon-14;
  • Study of plant growth;
  • Study of insect behavior.

Concept of Time | Physical Quantity | THEORETICAL PHYSICS

In physical terms, time is what clocks measure. This may sound unsatisfactory, but this definition corresponds not only to our everyday understanding, but also to Einstein’s theory of relativity. Einstein, after all, said that time is relative, and by that he meant that clocks moving through space at different speeds tick at different speeds.

This has also been proven: If you let a high-precision clock fly once around the earth in an airplane, then this clock goes slower than if it had stayed in place. And it does not go slower because it would have been braked in the airplane by something, but because the time really passes slower in fast moving bodies, relative to a static observation point.

Types of atomic clocks: CESIUM, HYDROGEN, RUBIDIUM AND STRONTIUM.
Types of atomic clocks.

So time in this sense is really what clocks measure. The unit of time, the second, is also defined only in this way. Except that the “clock” in this case is a cesium atom: A cesium atom “oscillates” about 9 trillion times a second, and therefore physics simply says: We define the approximately 9.192 trillion times this period of oscillation as a “second”.

This is the pragmatic definition – but how can we describe the deeper essence of time?

The question is: Should we think of time as something that is always “flowing”? Contemporary physics knows this: on the one hand, time – like space – is not something that simply exists independently of everything else. We often think of time as a grid between the past and the future that is “there” and then something “happens” in it. Einstein has shown that this is not the case.

Both space and time are created by matter and energy in the universe. At the supposed beginning of the universe, at the so-called big bang, these physical laws fail and it is not at all clear whether there was a time before the big bang or whether the time as such began to exist only with the big bang.

Also the question “What was before?” would not make sense any more, because if there is no time, there is also no “before” and “after”. Another phenomenon of time is that it is possibly “quantized” on a small scale. That is, metaphorically speaking, time does not flow evenly, but breaks down into small periods of time, which are of course much shorter than we can perceive.

One fundamental difference between time and space is that you can’t move backwards in time, right?

Video: The Arrow of Time

That is another characteristic: the so-called arrow of time. In our perception, time has only one direction. We can’t stop time, we can’t turn it back, it flows from the past into the future and separates cause and effect. The past is what has happened and cannot be changed, the future is up for grabs. This is amazing because in classical physics – and even for Einstein – time has no direction.

The laws of motion apply forward as well as backward. If I film a billiard ball as it rolls on the billiard table, I could also run the film backwards without it being noticeable. It’s different when I’m filming a sheet of glass breaking – here I can see immediately when the film is running backwards, when the pieces of glass reassemble to form the sheet. This is due to so-called entropy: events develop in such a way that the world as a whole tends to become more disorderly.

And if it does become more orderly somewhere – for example when we do the dishes – then this is only possible because we create disorder elsewhere – in this case in the wastewater. It is this increase in disorder that physically gives time a direction. Conversely, this means, the energy of the universe must have been extremely “ordered” at the beginning – otherwise the possibility of things getting more and more disordered wouldn’t exist at all.

Albert Einstein and His Top Five Discoveries

Einstein is considered the greatest of theorists, alongside Isaac Newton, the father of classical mechanics. His name has become synonymous with genius.

To commemorate him, we have compiled this list of his main contributions to physics:

1. Brownian motion:
This discovery, made in 1905, explains how the thermal motion of individual atoms can form a fluid.

2. The photoelectric effect:
Also discovered in 1905, it explains the appearance of electric currents in certain materials, when they are illuminated by electromagnetic radiation.

3. Special relativity:
This is another contribution made in 1905. It shows that the speed of light is constant, while position and time depend on the speed of the body.

4. Mass-energy equivalence:
1905 was arguably one of his best years. Yes, the discovery of this equation (‘E=mc²’) also occurred in that year. It shows how a particle of mass has an energy at rest, different from kinetic and potential energy. It is used to explain how nuclear energy is produced.

5. General relativity:
Published between 1915 and 1916, it describes acceleration and gravity as different aspects of the same reality. This theory, one of the best known and most applauded, postulated the basis for the study of cosmology and the understanding of the essential characteristics of the universe.

Highest and Lowest Temperature in the Universe?

We will start by explaining the physical phenomenon on which the temperature that something can have depends.

When the particles of an object move a lot, they generate heat, and the entity has a higher temperature. When particles move less, there is less heat, and the thing is colder. We can imagine a point where it is so cold that the atoms and their subatomic particles do not move. This point is called absolute zero (and in degrees, it represents −273.15 °C). At this temperature, the internal energy level is the lowest possible in this universe. The particles, according to classical mechanics, lack any movement or vibration.

Can an Absolute Zero Be Reached?

However, we have never been able to demonstrate this theory because we have never reached absolute zero. But we have been close, we have come very close. A piece of rhodium has been cooled to one ten billionth above absolute zero.

However, according to quantum mechanics, absolute zero must have a residual energy, the so-called zero point energy, in order to fulfill Heisenberg’s uncertainty principle. Fine, but we’re not going to stop here.

According to the third law of thermodynamics then, absolute zero is therefore an unattainable theoretical limit.

What Is the Coldest Place in Our Solar System?

All right, having said that, do you know which is the coldest place in the solar system? Pluto already lost its coldness status years ago, and its successor is neither Uranus or Neptune, but a little rock just around the corner.

Yes, you guess right. It is the moon. Incredible, but true. It was confirmed as hosting the coldest place in the solar system (that we know of), in 2009. Inside its deepest craters, where sunlight cannot access, a temperature of -248 degrees Celsius (-415 degrees Fahrenheit) was measured by NASA’s Lunar Reconnaissance Orbiter.

What Is the Coldest Place in the Universe?

But the coldest place in the known universe is The Boomerang Nebula, which is about 5,000 light years distant from Earth. Its temperature in some places is a staggering -272 ºC. Only one degree warmer than the lowest limit for all temperatures, absolute zero.

Well, let’s recall once again why it is not possible to cool an object infinitely. Temperature is a measure of how fast the particles that make up the object move. When we cool it down, its particles move more and more slowly, until they stop. That’s absolute zero. As the particles cannot move slower than “not at all”, it is not possible to cool it further.

Unless you have infinite time and resources, you cannot get to absolute zero temperature. Thus, reaching absolute zero is an impossible task, since there is always at least some type of vibration.

Now we know that there is a lower limit of temperature. Put another way, things can get very cold, but only up to a point – absolute zero. But, is there a limit on the other side?

Can Infinite Temperature Be Reached?

When a material is very hot, its particles have a large amount of thermal energy, and they move and vibrate a lot. That is, the opposite of when they are cold.

Solids melt and liquids vaporize, because their thermal energy exceeds the forces that unite atoms or molecules. At even higher temperatures, atoms dissociate into electrons and ion plasma (another state of matter). The more energy is injected into a system, the more its temperature rises But, high temperatures also have their limits.

The fundamental temperature on any scale is 100º, which marks the boiling point of water (but as we can suppose, this is very little).

What Is the Hottest Planet in the Solar System?

The hottest planet in the solar system is not Mercury as one might expect being the closest to the sun, but Venus. On this planet average temperatures reach 471 °C (880 °F). This record is due to its thick atmosphere that retains heat.

In 2017, a planet was discovered that is estimated to reach 4,300 degrees Celsius (7,770 degrees Fahrenheit). The funny thing is that the distance that separates it from its star is 650 times the distance that separates us from the Sun. Even so, it still reaches that staggering temperature. The explanation is that it always faces its star. Let’s move on to something substantially hotter than that.

Extreme Temperatures of Stars

A star like our sun has an average temperature of about 5,500 degrees Celsius (10,000 Fahrenheit) on its surface. At its core it can reach 15 million degrees (27,000 Fahrenheit).

Obviously, the larger the size of a star, the hotter the plasma inside it will be. There are stars larger than the sun, which can reach temperatures of over 200 million degrees inside. But in reality, that is also nothing when compared to other starry phenomena.

For example, when a very large star runs out of fuel but does not have enough mass to form a black hole. The supernova with which it ends its life leaves behind a neutron star. At the beginning of their life, these stars can reach temperatures of up to 1 trillion degrees. Although they cool down very quickly, and within seconds their temperature drops to a “refreshing” 100 million degrees.

What Is the Highest Temperature Produced Artificially?

That trillion degrees reached momentarily probably seem outrageous to you. But when the Large Hadron Collider smashes lead ions together, the collisions regularly reach temperatures of 5.5 trillion degrees Celsius. But as incredible as it may seem, nature has outdone us once again.

In 2016 Russian scientists measured the temperature of a quasar called 3C 273 located more than 2 billion light-years from Earth. The result they got defies logic. They revealed that it was hotter than 10 billion degrees!

Is There an Absolute Hot?

Okay, so are quasars the hottest thing you can find in the universe? Can a maximum temperature be reached?

Classical mechanics do not predict any upper temperature limit. In fact, many textbooks gleefully state that the temperature can rise to infinity. However, according to modern physics, it is not possible to reach an arbitrarily high temperature.

Because if there is a limit to the total energy that exists in the universe, there is also a maximum possible temperature.

The highest temperature reached in the history of our universe is the so-called Planck Temperature. Some scientists believe that it occurred just after the Big Bang. This temperature would be equivalent to 1,416 × 10 raised to thirty-two. At these temperatures the energy of the particles is so high that it is not known how matter would behave. From this point, things get pretty confusing for today’s physics.

To give us an idea of this huge figure, the core of our sun would be 10 trillion times colder. So, the maximum temperature limit value is the Planck temperature. It is the highest possible temperature in our universe, and it is the opposite of absolute zero.

Why Are Some Metals Attracted to Magnets and Others Are Not?

To keep it simple, when it comes to magnetism there are three main types of materials:

  1. Ferromagnetic: Which are strongly attracted by magnetic fields, and are mainly alloys of iron, nickel and cobalt; note that these three metals are adjacent in the periodic table.
  1. Paramagnetic: Which are weakly attracted by magnetic fields, such as oxygen.
  1. Diamagnetic: Which are weakly repelled by magnetic fields, for example aluminum.

This characteristic is defined as “magnetic permeability”. The structure of permeable materials allows magnetic-field lines to pass through the material easier than through a vacuum. 

So the high concentration of magnetic-field lines causes the material to be attracted to the magnet. Conversely, when magnetic lines go through a vacuum easier, then the material is repelled.

This is the reason why two magnets of the same polarity repel each other. The magnetic lines of one magnet are prevented from passing through the lines of the second one, so it passes easier through a vacuum, causing equal poles to repel each other.

All substances are affected by the magnetic field, although in most of them the effect is very weak (and can only be detected with precise instruments). Materials attracted by magnets fall into two groups: ferromagnetic materials and ferrimagnetic materials. The other materials not attracted to magnets are classified as paramagnetic, diamagnetic and antiferromagnetic.

At the end of the 19th century, the microscopic causes of the different magnetic behavior of materials began to be investigated. Surprisingly around 1910, it was shown that in the framework of classical statistical mechanics, ferromagnetism was inexplicable within classical physics.

This devastating result became known as the Bohr–van Leeuwen theorem. This was in addition to previous devastating results: the existence of stable atoms was inexplicable within classical mechanics, light behaved as a wave and a particle at the same time. All these problems were related and could only be overcome with the advent and development of quantum mechanics.

Ferromagnetism is, therefore, a phenomenon essentially related to the quantum behavior of electrons within an atom. It turns out that electrons have a special quantum property called spin. This spin is affected by the electromagnetic field and is capable of magnetic attraction (all macroscopic magnetism is due to the presence of this spin in matter). That said, we are in a position to try and explain the difference between ferromagnetic / ferrimagnetic materials and the rest.

It turns out that in this type of material the spins (which can be imagined as vectors that point in different directions) are more or less disordered.

In the presence of a magnetic field these spins are oriented parallel to the magnetic field and together create an angular magnetic moment effective.

It in turn interacts with the original field (as when two wires carrying current are placed next to each other) and the attractive force is produced.

This happens because the structure of ferromagnetic materials includes a partially empty electron shell that allows realignment of spins. In materials that are not attracted by magnets, the outer shells are full and the spins have no possibility of reorienting freely.