aliencatadventures

[aliencatadventures]

Beaver supermoon.

(November 15, 2024)

[aliencatadventures]

Sunspot formation | john.purvis on Flickr

[aliencatadventures]

The Mysteries of our Sun. Part 3

Part 1 is here; and part 2 is here.

Before diving into the Sun's magnetic fields, let's first understand magnetic fields in general.

Many celestial objects in the Universe have magnetic fields. But what are they, and where do they come from? What does it mean to "have a magnetic field"? Earth, for example, has a magnetic field; we’ve known this since childhood. We also know that a compass needle will automatically align itself to point north because invisible magnetic field lines are everywhere, guiding the needle to turn in the correct direction.

And if you place a magnet and sprinkle iron filings around it, the filings will align themselves along the magnetic field lines.

So, what is a magnetic field?

Let’s start with something simpler: the electric field. It’s pretty straightforward. For example, take a negative charge, like an electron, and a positive charge, like an ion. If you place them near each other, they will attract. If you place particles with the same charge, like two electrons or two ions, they will repel. This "something" that causes attraction or repulsion is called an electric field.

An electric field forms when there’s a concentration of charges somewhere, creating a force that pushes or pulls other charges nearby. The field always points from one charge to another or between groups of charges.

The organized movement of charged particles in an electric field is called an electric current, and these currents always move in the direction of the electric field.

An electric field, like a gravitational field, diminishes with distance. At a great enough distance, particles might simply not affect each other and continue moving on their own, following the path they were already on.

However, when electric charges sense each other, an electric field forms. If there is a conductor that allows the charges to move, they begin to flow in the direction of the electric field, i.e., either toward each other or in the opposite direction, depending on their charges. This movement brings with it a mysterious companion of the electric field—the magnetic field. Have you seen how sci-fi movies depict a ship passing through a portal, with waves radiating outward in circles around it? Similarly, "rings" of magnetic field form around the charges as they move toward one another.

So, when an electric current flows, for example, moving in a straight line through a metal conductive wire, a magnetic field begins to circulate around the wire.

The direction of the magnetic field can easily be determined using the right-hand rule. Give a "thumbs up" to the current—if your thumb points in the direction of the current in a conductor, your other four fingers will curl in the direction of the magnetic field around the wire.

Let’s repeat and remember this—it’s very important: a magnetic field arises as a result of the organized movement of charged particles under the influence of an electric field. For example, in a simple school experiment, if we place a positive charge on one metal plate and a negative charge on another plate nearby, an electric field will form, but no magnetic field will appear. Why? Because the charges are present, but they are not moving.

However, if we connect these plates with a wire, for a fraction of a second, a current will flow from one plate to the other as the charges rush toward each other. It is at that moment that a magnetic field will form around the wire—also for just a fraction of a second.

You might already be wondering—why am I telling you all this, and what does it have to do with the Sun and planets? It does! Bear with me a little longer, and we’ll trace this path to the Sun, Earth, and other stars and planets.

So, a magnetic field forms around a wire carrying current. But what happens if we place several wires next to each other and run current through them in the same direction? Will each wire still have its own magnetic field? Yes, but the individual fields will combine, creating a single magnetic field that surrounds the entire bundle of wires. As a result, the wires will attract each other. On the other hand, if the currents in the wires flow in opposite directions, the wires will repel each other.

And what happens if we wind the wire into a coil and connect its ends to a battery? Current will flow through the wire, and a magnetic field will form both inside and outside the coil. Let’s recall the "thumbs-up" rule we used for current, but now, if the direction of your four fingers follows the current in the coil (solenoid), your thumb will point to the direction of the magnetic field inside the solenoid.

This solenoid will now act like a real magnet, capable of attracting all sorts of iron objects to itself.

Wait a minute, what currents exist in a magnet? Are there really currents in there? The trick is that currents do indeed exist in a magnet, flowing inside and along its surface as if a long wire were coiled around it. This is why the magnetic field in a magnet is arranged just like in a coil, with distinct north and south magnetic poles.

But why are there currents in a magnet? Because magnetic materials have a unique property: the motion of their electrons within the crystalline lattice is highly organized. This creates an effect similar to currents flowing along the surface of the magnet, generating the magnetic field.

And take note: the image of the coil and the magnet (above) closely resembles the depiction of Earth and its magnetic field (on the very first image in this post). This means that currents flow not only in magnets and coils with current but also inside our Earth, the Sun, and many other stars and planets. These currents flow as if a coil of wire were wrapped along the Earth's axis.

Inside the Sun, the picture is very similar, but only when the Sun is "calm," as we say—like a freshly made coil straight from the factory. However, when the Sun is "active," its magnetic field looks as if playful kittens had been toying with that coil—chaotic loops of magnetic fields now stick out in all directions.

But I’ll tell you more about that in the next episode.

[aliencatadventures]

The Mysteries of the Sun. Part 2

Credit to #NASA

The Mysteries of the Sun. Part 1

So, any small star, like our Sun, consists mainly of hydrogen and helium, gradually converting one into the other. These are gases in a plasma state, meaning the gas molecules have broken down into nuclei (positively charged ions) and negatively charged electrons. Near the Sun's visible surface, the atmosphere is very sparse, and the deeper you go, the denser it becomes. Initially, the gas takes on a texture similar to liquid, then this liquid becomes thicker, resembling Earth's magma. At the very core of the star, the pressure and density are so immense that the environment is akin to a hot, dense core, where atoms can no longer move relative to each other.

And if the Sun's surface rotates in that strange way we mentioned—where the equatorial part completes a rotation every 27 days—scientists have recently discovered that the core rotates even faster, completing one rotation in about a week. What's more, the core is slightly offset from the Sun's center.

As I mentioned in our previous conversation, convection cells form on the Sun's surface due to the flow of hot and cold matter: hot masses rise to the surface, while cooler ones sink. This happens both in the thin atmospheric layers, where these cells are small, and deeper within the star. The deeper you go, the larger and more global these flows become. The most significant process carries matter from the dense core of the star toward the equatorial region.

Imagine a ballerina spinning with her skirt flaring outward—something similar happens inside the star. Masses of solar material rise in the equator area from the depth toward the surface under the influence of centrifugal force. However, gravity pulls them back, preventing them from escaping too far. As a result, streams of solar matter spread across the surface from the equator toward the poles—north and south—cooling as they move.

But despite all the complexity of the Sun's activity, this is actually the simplest part of its fascinating internal dynamics. Next time, we'll dive into the even more intriguing topic of magnetic fields and electromagnetic processes.

The next part 3 is here

[aliencatadventures]

The Mysteries of the Sun. Part 1

image: credit to #NASA

Can there be order in chaos? Is it possible to poke a hole in the atmosphere? Can one part of a celestial body rotate at one speed while another part rotates at a different speed? These might seem like foolish questions, wouldn’t they? But it turns out they aren’t. Such fascinating phenomena are found not just anywhere, but right in our own neighborhood, near our star—the Sun.

You surely know that the Sun rotates around its axis, just like many other celestial bodies. Some rotate faster, others slower. Some spin very slowly. The Sun also rotates, but in a very peculiar way. The equatorial part of the Sun spins at one speed, while the polar regions spin at another. Let's note, for example, a point on the solar equator... Wait, how is this possible? The Sun is a giant boiling cauldron, its surface composed not even of hot gas, but of hot plasma. There is fiery chaos on the Sun. How can you stick a pole into it somewhere on the equator or at high latitudes to track when this pole disappears from view and when it comes back into view to determine the speed at which the Sun rotates around its axis? Where is that stable object, fixed in place, that you can observe to determine the rotation speed?

Image: credit to #NASA

The temperature of the Sun, like that of any star, is extremely high. It is believed that deep within the Sun, it reaches many millions of degrees Celsius, while on the surface it is only about 6000 degrees. However, in science, temperature is measured in Kelvin, and on this scale, the surface temperature of the Sun is also around 6000 degrees. The exact number isn't important here. What matters is that the temperature is so high that the gas atoms making up the Sun's atmosphere cannot remain intact and disintegrate into their components: electrons jump off their orbits, leaving the atomic nuclei to move separately.

Do you remember from your school courses the three main states of matter? The first is solid, where atoms are arranged in a lattice, standing in neat rows. The second is liquid, where atoms are heated and escape from the lattice, moving freely but still maintaining bonds with each other. The third is gaseous, where with even more heating, atoms completely lose their bonds and disperse as a gas. Plasma is the fourth state of matter, where with further heating, the atoms themselves disintegrate into their constituent parts: atomic nuclei, which have a positive charge, now fly separately from their electrons, which are negatively charged. So, we have not just a gas, but a charged gas that responds to electric and magnetic fields.

Image: credit to #firefly.adobe

So, the Sun is extremely hot. It’s like a large boiling pot, heated from below by a burner reaching several million degrees. You might think that at such temperatures, the Sun would be a scene of complete chaos and nothing else! But no — even in the most bubbling, boiling pot, there is an internal order, strange as it may sound. Boiling, despite all its apparent chaos, is not entirely chaotic. This was noticed by a scientist who began observing oil in a hot frying pan. He saw that even with perfectly even heating, the hotter and thus lighter oil in some places rises from the depths to the surface, where it spreads out and cools, while in other places, the cooler and thus heavier oil sinks downward. This creates stable convection structures that were named Bénard cells after the scientist. Another name for them is Rayleigh-Bénard cells, including the name of another scientist who also studied processes in heated mediums. And this is what it looks like:

Image: Credit to https://instructional-resources.physics.uiowa.edu

The process of heating and cooling in the Sun's atmosphere, as well as in other stars, follows a similar pattern. In the Sun's upper atmosphere, this phenomenon closely resembles the behavior of Bénard cells. These temperature-exchange cells can vary in size, and within the Sun and other stars, large-scale heat exchange is organized into even bigger cells, encompassing massive, complex processes.

Image: Credit to https://physicsworld.com

The heated masses from the Sun's interior flow from the poles toward the equator, where they rise to the surface. Once at the surface, these masses flow toward the poles, cooling as they travel. In the polar regions, the cooled solar plasma begins to sink back toward the Sun's core, completing the cycle as it flows back toward the equator.

Credit: Mystery of solar cycle illuminated

This process is not unique to stars—it also occurs in Earth's oceans, where water heated at lower latitudes is carried by currents to cooler regions, creating stable flows. Similarly, within the Earth, hot magma follows comparable patterns, gradually driving the movement of continents. Wherever there is a heat source on one side and cooling on the other, these processes emerge. Even in a simple room with a heater, air forms currents that circulate along specific paths. Warm air rises as it heats, then sinks as it cools, naturally forming stable currents, provided there are no significant obstacles to disrupt the flow. This process is called convection. In the case of large masses of air, water, or other media moving in a horizontal plane, it is called advection. Here, we are not dealing with small (comparatively) cells where heat exchange occurs, but with global flows comparable in scale to the size of a planet or a star.

And how all these processes manifest on the Sun will be explained in the next talk. Stay tuned!

[aliencatadventures]

Black Hole and Cosmic Lensing

Once in my early youth, I watched a sci-fi movie about space travel that supposedly featured a black hole. It resembled a galaxy, which I found quite amusing—how can you see a black hole if no light can escape from it? Much later, I realized that although the depiction in the movie wasn't accurate, and yes, we certainly can't see the black hole itself, there are still many fascinating phenomena around it that can be observed. So, what exactly can we observe?

First, imagine Saturn with its majestic rings. Then, imagine this Saturn turning black, becoming invisible—and you'll get the picture. There are luminous rings rotating around something that, in reality, we cannot see. But it's definitely there. These rings, or more accurately, the matter drawn in by the black hole, spin at tremendous speeds and are located in the equatorial plane—just as in any galaxy formed around any massive celestial body. Unlike the tranquil, icy rings leisurely circling our native gas giant Saturn, this matter is accelerated to nearly the speed of light. It may be dense and heated near this celestial body and becomes more sparse and slower farther away. Another way to visualize it is like a whirlpool, only much faster.

But in the picture (below), it doesn't quite resemble rings. It looks more like a strange, faceless smiley wearing a hat, reminiscent of what some viewers might have seen in the movie 'Interstellar.' The reason is that space is distorted so much, so what lies behind this celestial body appears partially above and partially below it. The image seems almost turned inside out. Thus, the depiction is akin to Saturn's rings, if they were reflected in a curved mirror, or more accurately, viewed through a powerful lens.

I highly recommend clicking on the link on the video (below) to see it in action - it's absolutely spectacular!

Also, if you haven't seen the movie 'Interstellar,' I strongly suggest watching it. A group of scientists, including Kip Thorne, participated in its production. Thorne even wrote a book titled 'The Science of Interstellar' with scientific explanations. He explains how the film crew aimed to create images and visualizations as close as possible to what is actually known in science, or at least to use real scientific hypotheses. For the visualization of the black hole, they employed real scientific models, and the visuals were based on the latest scientific understanding. This approach was validated by the recent actual photograph of a black hole.

In this visualization (below), it’s easy to observe dynamically why the rings around a black hole take on such a peculiar shape. The image displays a computer model showing how a black hole would appear if it passed in front of a distant galaxy. Note that the galaxy itself remains unaffected; it is far away, and nothing is happening to it. It's just the image of the galaxy that changes - it resembles what you would see if you took a thick, convex lens and moved it across the backdrop of that same galaxy or a simple geometric pattern. If you have such a lens or a glass sphere, try this experiment. It’s a straightforward way to help understand this phenomenon

So, the biggest difficulty in understanding is that the picture appears static to us. As soon as you see it in motion, there's a moment of recognition of the phenomenon, and then it's no longer a problem to understand why you see rings both around the shadow of the black hole and above and below it.

Furthermore, the ability to view images dynamically also facilitates the discovery of new black holes. When astronomers notice that an entire sector of a previously familiar scene begins behaving strangely — with stars moving erratically or stretching into curved lines, and the image becoming blurred — it strongly indicates the presence of an invisible object traveling between us and this background scene, distorting the image. But we'll discuss this in more detail next time. Stay tuned!

[aliencatadventures]

Fluid Acrylic Cosmos. Real Artwork

[aliencatadventures]

The Big Bang Theory and the Art of Packing. Part 4

Hello again, my friends! Get ready to dig into more of the Universe's secrets. We've been having atom-splitting adventures in Part 1, Part 2, and Part 3, and now we're diving into the mighty power of atoms.

First, scientists tell us that inside a star, a process occurs that’s somewhat like a cosmic magic trick called inverse beta decay. You might remember that in the direct beta decay, a neutron turns into a proton, an electron, and something extra. But in inverse beta decay, the script is flipped: a proton and an electron crash into each other so hard that they merge to become a neutron.

Now, try to picture this: If the gap between an electron and a proton were as big as a giant Ferris wheel, and the proton was just a grape sitting at the center, imagine the incredible amount of space that gets "squashed" when they combine. It's like fitting the Ferris wheel into the grape—that’s the kind of cosmic compression we're talking about inside a star!

Think about this: a star, perhaps as heavy as dozens of suns and stretching across millions of miles. But then, something incredible happens – it collapses, turning into a neutron star. Surprisingly, its mass doesn't change much, apart from some material that shoots away into space during this cosmic transformation. But here's the real twist: this newly transformed star isn't huge anymore. Its diameter doesn't measure in millions or even thousands of miles. It shrinks down to a mere 12 miles across. That's roughly the distance that an average city dweller probably covers every day, commuting from home to work and back.

But this is still not the limit of compression. Because at one point, the boundaries between particles might collapse, and the star might compress into a quark star, which means it becomes even smaller in size.

Do you think we've hit the limit? Not at all.

We're aware of black holes—cosmic entities where stars, some weighing tens to millions more than our Sun, cram themselves in. It's hard to imagine just how much an atom has to shrink, getting compressed into a minuscule particle, so that there's absolutely no millimeter of empty space left among these proto-particles. Not a micrometer, not a nanometer, not even a pico-, femto-, atto-, zepto-, or yoctometer—no space whatsoever. Nothing. Zero. We've hit the atom's ultimate limit of being divided. We've witnessed what I'd call 'proto-sand' that filled up a 'proto-sandbox.' This forms a cosmic body that, despite its massive weight, has practically no size we can measure. Pretty wild "nothing," right? But what kind of "nothing" is it if it's as massive as a colossal star with the mass of a million suns? And what if several such black holes merged?

Or picture if the entire Universe squeezed into an object like this… Can you imagine that— the mass of the Universe compacted into "nothing"?

And if this 'nothing' were to explode one day, if there could be some observers around (which is not quite possible), they would witness a new Big Bang, giving rise to new stars and galaxies. And then, the entire cycle would start anew…

Do you want some more cosmic adventures? You welcome! We are going to explore the Universe. Ask your questions, my brave young friends, and you'll get your answers!

[aliencatadventures]

The Big Bang Theory and the Art of Packing. Part 3

Welcome back, cosmic adventurers! Get ready to plunge into the universe's mysteries as we journey deeper, unveiling even more mind-bending cosmic secrets!

Before we continue our journey (please see the Part 1 and Part 2), let's take a little journey deeper into the world of particles.

Those protons and neutrons that initially appeared to be the indivisible building blocks turned out to be quite divisible themselves. They are composed of particles known as quarks. Each neutron and proton consists of three of these particles. Quarks come in various types, and scientists wrestled with naming them, assigning colors, and defining other characteristics for quite some time. But that's not our focus right now. What's important is that protons and neutrons are now made up of these quarks and some empty space in between. And it's entirely possible that this might not be the limit of their division.

Okay, let's take a breather. Now we know that the supposedly indivisible atom can actually be divided into many parts.

Now, picture this: somewhere in the Universe, particles or atoms are drifting about. They move close to each other, and this mutual proximity causes them to be drawn together. Slowly accumulating into a massive cloud, they exert gravitational pull on other particles and atoms, resulting in an ever-increasing congregation. The larger the assembly grows, the stronger its gravitational attraction becomes. And so, this process continues. As time elapses, a hazy cloud forms, gradually coalescing into a celestial body, primarily composed of hydrogen atoms and their constituents: protons and electrons. It's evident that within this celestial body, the densest region resides at its core. This central space becomes exceedingly cramped as everything else compresses towards it. Similar to how ocean pressure rises with depth, the same principle applies to gaseous formations. The higher you ascend, the thinner the atmosphere, akin to Earth. Conversely, as you descend deeper, it becomes denser.

Now, let's imagine what occurs deep within the Mariana Trench on Earth. The pressure there is so immense that it could crush a submarine like an eggshell. Surprisingly, an ordinary atom in the Mariana Trench manages to feel quite at ease.

Now, picture this: the unfathomable depths of the Sun or another star. At these extreme depths, even these atoms start to feel uncomfortable. What if it's a star several tens or hundreds of times the mass of our Sun? The atoms deep within these celestial bodies begin to feel incredibly unwell. They can barely withstand the tremendous weight pressing down on them from above.

And one day, the atoms in these depths can't endure it any longer! They cave in!

But this new twist we are going to discuss in the new chapter! Stay tuned!

[aliencatadventures]

The Big Bang Theory and the Art of Packing, Part 2

Welcome back, cosmic explorers! If you're ready to dive deeper into the wonders of the universe, buckle up because we're about to embark on another exciting journey --- of these tiny things we discussed earlier.

You might recall that scientists found out that the world is made up of protons, electrons, and empty space. Protons, with their positive charge, reside at the center of the atom, called the nucleus, while electrons dance around them. But then something intriguing happened: scientists realized that the number of protons in the nucleus determines the properties of matter. A single proton in the nucleus creates hydrogen gas, two protons form heavier helium gas, and three protons result in the creation of metallic lithium! This discovery revealed that the characteristics of substances change significantly based on this number. So, scientists created a table of elements based on the number of protons in the atom's nucleus.

Then people found ways to measure the weight of the atomic nucleus and realized that there were not enough protons for the mass they observed. So, the scientific minds concluded that besides protons in the nucleus, there must be something else with mass but no charge. And that's precisely what they found. They discovered a particle with a mass roughly similar to that of a proton but electrically neutral. They called it a neutron, to keep things simple. Besides, there were many other intriguing things inside the nucleus, but we'll discuss that another time.

In the process, it was also discovered that a proton is a very stable particle, one of the fundamental building blocks of the Universe. Some of the protons inside our bodies or our planet have existed since the time of the Big Bang — billions of years. Can you feel it? Can you grasp it? Quite astonishing!

But what about neutrons? Well, they have a tendency to fall apart. This process is called beta decay, where a neutron splits into a proton and an electron. And a little something else, but we'll leave that for now. Inside the nucleus of each element, protons and neutrons coexist quite harmoniously, holding on tightly to each other and not eager to break their embrace. And electrons (which also turned out to be very stable particles) zoom around at a distance we've already discussed.

And it should be mentioned that they orbit in specific orbits. Each electron has a personal orbit, and these orbits never intersect. They are arranged like layers or nested dolls, with significant empty space between them. No electron can occupy an orbit already inhabited by another electron. It's not allowed, following Dr. Pauli's rule, or rather, the Pauli exclusion principle. It's forbidden, absolutely not allowed. And the electrons obey Dr. Pauli. Well, most of the time. But there comes a moment when…

Eager for more cosmic revelations? Stay tuned for our upcoming cosmic odyssey!

[aliencatadventures]

The Big Bang Theory and the Art of Packing. Part 1

Terry Pratchett once said, "In the beginning, there was nothing, which exploded." That's kind of how many people imagine the Big Bang. But there's a big difference between the "nothing" in our heads and the real-deal "Nothing" that went kaboom. And that's what we're diving into now. What exploded and why? What was there that, when it exploded, gave rise to the entire Universe? And how did it get packed into that teeny-tiny point?

Let’s begin.

Remember those atoms we learned about in school? They're like the tiny building blocks of everything around us. A long, long time ago, a couple of smart folks from ancient Greece, Leucippus and Democritus, were doing something as ordinary as watching linen dry. But they realized something weird – water seems to disappear when it's spread thin. Now, other people probably noticed this too, especially the women who put out the linen to dry, but it was these two who decided to put on their thinking caps. They said that water consists of very small things, and they gradually disappear. They gave a cool name to these tiny things that make up stuff – "atoms." They thought these atoms couldn't be split any further. Funny thing is, they were wrong about that, but they had no clue. They happily believed they'd figured out the secrets of the universe.

So, they said, the world consists of little atoms and empty space.

Time rolled on, and once upon a time, people found out that the world isn't as simple as they thought. Those "can't-be-divided" atoms actually can be taken apart. First, scientists divided the atom into two main things – a proton and an electron. The proton is positively charged and proudly sits in the center of the atom, while the electron is negatively charged and orbits around. And scientists decided that these are now the indivisible parts. A proton is a big thing, and an electron is small, about 1,000 times lighter. They were often depicted as one big ball in the center and another one orbiting. However, this was just the simplest hydrogen atom, which has only one proton and one electron. Other atoms turned out to be a bit more complex - they had several protons in the center, and several electrons orbiting, but still, it was a beautiful and clear picture, so scientists calmed down:

The world consists of protons, electrons, and empty space.

However, it turns out there's a surprising amount of emptiness. Picture the simplest hydrogen atom as large as a giant Ferris wheel. Now, imagine the proton at its center, it's as small as a grape or a bead. And the electron? It's something much tinier, whirling around the wheel. Everything else? Well, it's just empty space.

But if there are several protons at the center of the atom, called the nucleus, then there are many more electrons orbiting around. Each one is on a different orbit, and these orbits are located farther and farther away from that same nucleus. We're talking several times the radius of the wheel or even dozens of times.

Curious for more quirky facts? Stay tuned for our next post!

[aliencatadventures]

Scientific Consensus

Let me make it clear: there is no such thing as consensus in science! It is like a unicorn; it does not exist. Well, may be in the perfect future, when people will have all the information about the world discovered, it will be. But not before. Right now, real scientists don't have agreement about any scientific issue: time, matter, particles, climate, black holes, etc. And they shouldn't! Some people still have strong intension to prove Einstein is wrong, and there is nothing wrong with this intension. May be they'll even succeed. But when hundred authors published a book against Einstein, he said that if he is wrong, one would be enough.

There is no democracy in science. Scientific truth cannot be agreed upon by voting. It does not work this way. If we could allow consensus in science, we would still believe that the Earth is the center of the Universe and it is flat. Or we would believe into many other theories science get happily outgrown. But all the scientific discoveries and all the great steps of real science were made by people, who disagreed with scientific community and the set of dominating beliefs and ideas. 

I repeat: there is no consensus in science. If there is consensus, it is not science, it is religion. And even when a huge crowd of best actors, politicians, and their admirers pronounce some statements, it does not make these statements true.