"The Sun" <i>We all see the sun everyday,</i> <i>but no one knows its origins.</i> <i>You...</i> <i>I'll make you a star!</i> "The Sun": I'm sun, the star of the solar system. "Earth": Since I've met sun, and he's an energy source for all of us, he has good vibes, he's nice, decent, and respectable. "Mercury": He's a huge star whom we all love, he's full of warmth and kindness, and he considers me the closest! But I had a request, I wanted to change my place, and I never got a response.
And as you see, I'm melting. <i>Who do you think are this generation's stars?</i> "The Sun": They are a lot, there are many stars in this generation, Bruno...Mars, Star...set, Mohamed Moon-ir, such a star, God bless him.
The moon is passing by... "Earth": He just shy-eclipses sometimes... No one looks, guys.
A dream...of course being international is a dream, everyday, I stand in front of the mirror and ask myself, I'm the center of the galaxy now, why don't I go bigger? Why not the center of the universe? or head of the Musicians' Syndicate? Why not? Why not? Hello my dear viewers, Welcome to another episode of ElDaheeh. The human history is filled with weird and awful years, and since you're a good follower of ElDaheeh, so you know some of them Like 2008 and the Global Financial Crisis, or 2020 when ElDaheeh stopped airing, and there was a flu or something going around, and all over the world, called Coven or Covid, something like that.
Continuing the series of these unfortunate years, I want to introduce you to the year 1054. In his book, "Uyūn ul-Anba fī Tabaqat al-Atibba" the Syrian doctor and historian, Ibn Abi Usaybiaa, writes on a tough period that the region witnessed. "The destruction of Iraq, Mosul, and Peninsula, and the disorder in Diyarbakır, Diyar Rabi'a, Diyar Mudar, Fars, Kerman, Morocco, Yemen, Fustat, and the Levant. The kings of the world's affairs were in disturbance, and the abundance of wars, inflation, and epidemics." That's besides his writings on the Nile flood that filled Egypt. And the epidemics that spread in Constantinople, and killed huge numbers of people, till all the graves are full.
Imagine having waiting lists on graves. All that on one hand, and what I'm about to say is a on a whole other hand. You might wonder, what more could happen, Abo Hmeed? In a night on 4th July 1054, suddenly without any warnings, some bright spots appear in the sky, glowing with light.
This light was brighter than the moon's, and the people saw it even in daylight when the sun was up, for around 23 days. This was seen by many people in different parts of the world, not in just one place. What's happening, people?! This event was so unique and weird, that Ibn Abi Usaybiaa called it the "Trail Planet". Despite all the problems and epidemics in that year, it was actually remembered by the appearance of this plant in Gemini in the sky. Actually, Ibn Abi Usaybiaa wasn't the first or the only to write on this phenomenon.
Similar events had happened in the sky millions of years ago in different locations. They were documented by Arab, Asian, and European scientists and historians. The Chinese in particular called it the "Guest Star", because it always appeared unannounced and then disappeared again. The oldest records documenting this phenomenon, go back to more than 4000 years BC, in Burzahom in India. and we have historical records by people like Ibn Sina, Ali ibn Ridwan, and Ibn Al-Diba'i.
He was with them? He asked for you. By the way, Ibn Al-Diba'i wrote an accurate description of a similar event that he witnessed in 1006 and said; "It was middle of Rajab, 396 AH, on the night of the 15th, a star appeared from the east four times bigger than Venus half an hour after sunset, and it wasn't round but oval, and its edges had branches like fingers, it had a great motion as if it's swimming in water, and rays like the sun's, it came out in Libra from Scorpio, and remained that way till the night of the 15th of Ramadan, then its light fainted till it's gone." Of course, you're now wondering, what's a trail planet and a guest star? Is there a star other than you? Anyway, this stellar phenomenon remained a mystery for many centuries.
Because there wasn't any tools or scientific systems that would explain it to people and assure them. Some cultures saw them as prophecies to natural disasters or a ruler's death. Other cultures saw it as a good omen. But in reality, as you realized for sure, that this phenomenon wasn't a sign of apocalypse or good news.
We don't sell nonsense. But among the first people who analyzed it scientifically and modernly, was the Danish astronomer Tycho Brahe, who said that as he was contemplating the sky at night as usual he saw a star brighter than the others, but it wasn't there before. He expected it was new type of stars, and was seconded by the German astronomer Johannes Kepler, who in his book "De Stella Nova" drew the location of a star, with the same descriptions written by Brahe. But the matter still remained a mystery. We still considered it a new type of stars that we didn't have enough data on, and it appears and disappears randomly with variant levels of brightness, but strong at the same time. Till the thirties of the last century, when the truth of this phenomenon started to emerge, when the German and Swiss astronomers, Walter Baade and Fritz Zwicky started researching this type of stars, with advanced technologies and methods that weren't available to previous scientists.
Like using a 2.5 meter-long reflecting telescope, which was a relatively new method in studying light emitting from stars, called Astronomical Spectroscopy. It's a hard one.
It's analyzing the light emitting from the star, into its component spectrum. And through this analysis, we find out the chemical elements of this star. This exacts star. What does this mean? Let's take the closes star to us, the sun, let's take it as an example. "Light Source-White light-Prism" The sun emits a white light, when we analyze this white light into its component colors, the spectrum, and see the amount of each color in sunlight, we find that the sun emits green light more than the red light, Really? And emits purple light more than green light. So we call this the sun's stellar spectra.
You might ask me, why does this stellar spectra change from a star to another? They're all star anyway. Actually, my friend, the different amounts of light emitting from stars depend mainly on the chemical elements composing the star itself. When we analyze the light spectrum, and see the amount of each color; yellow, red, green, we can deduce that a star like the sun has Hydrogen as its main component. Of course there are other elements, but Hydrogen is the most important.
All this is short for many details, but that's just the broad image. That through analyzing the light you receive from a star, you can know the star... without getting to know it. This is very serious, my friend, all what you need now is analyzing the light coming from a star and know its components.
And for the first time in the history of humanity, we can solve the mystery of the essence of the stars that we couldn't solve for thousands of years. We can determine stars' essence while being on earth, millions of light years away! You'll tell me, Okay Abo Hmeed let's take this Astronomical Prosocpy and analyze this Guest Star. It's called Astronomical Spectroscopy, you idiot. You're not just saying it wrong, my friend, but it's also an old idea. Scientists Fritz Zwicky and Walter Baade, studied these guest stars, after Walter wasn't a Baade person anymore. They discovered that they aren't exactly stars...
Fake ones, Abo Hmeed? but actually a huge explosion cloud that happens at the end of a star's life. They called this phenomenon, Supernova. Stars are just like us, my friend, they are born...they age, live and die. In its life, it can meet other stars, sometimes they can be attracted to each other, and rotate around each other for thousands of years in close orbits, and if they liked each other and got too close, they merge and become one star.
But that's not always the case. Each star has its own life story, and evolve according to the time and location of its birth. Before we go back to our guest star that turned out to be a star's explosion, and ask him about his life story, let me tell you about an important physics law that we'll need, and it's the Universal law Gravitation. The Secret, Abo Hmeed? No. This law was established by Issac Newton in his book "The Mathematical Principles of Natural Philosophy" in 1687.
This law simply states that there's gravitational force between any two bodies with mass. And you can calculate this force using this simple equation. We won't dive into the equation's details, but the general idea is that any two bodies with mass will attract each other. The more the mass of each or both bodies increases, the more the attraction force between them increases. And the less the distance between them gets the more the attraction force increases. This force is what makes the stars.
The star starts its life as a huge cloud in space, called the stellar cloud, just a random cloud in the vast space, made up of gases, hydrogen, dust, and plasma. Plasma is also gas but with electric charge. All these are the raw materials of which the star would be made. These elements aren't found in a uniform way in the cloud, they're a mix, some more gases here.... more spice there, it's a mix. It's a random distribution of all the elements, that will form our star.
Over time, which is millions of years, this cloud starts to have clusters and collections, the dust and gas start to cluster together and group, and suddenly the cloud starts to have areas of more mass than other areas. What happens then, my friend? We start to see the effect of Newton's Gravitational law, so this clustering starts to attract the clusters of dust and gas that are lighter in the rest of the cloud, and step by step, the cluster inside starts to engulf and get bigger. It gets heavier and heavier in a process called Accretion. Then after a few million years, the cloud turns into a huge ball still of gas, dust, and plasma, or known as, a Protostar. Not a star yet, my friend, just a protostar.
It's still a star-to-be, not a star. All titles preserved. This star-to-be has huge amounts of the simplest element in the universe, Hydrogen; just one proton with one electron around it.
It doesn't get simpler. But over long periods, millions of years, we're talking big numbers, this protostar contains huge amounts of hydrogen, whose mass is massive, and mass equals gravity, so the mass starts pushing against itself due to its own gravity! Imagine a massive ball of hydrogen, the gravity of its center would attract its edges, so after all this pushing and squeezing, you would find hydrogen merging with the one next to it, and pressured into another hydrogen. and if that force is strong enough, it leads to Nuclear Fusion. This fusion produces two things, the second simplest element in the universe, Helium, and immense amount of energy. As you know, for this process to occur it needs massive force, to pressure a hydrogen atom and force it to merge with another, but as we said, the star has to reach the suitable size and mass, for the gravitational force to be enough to start this fusion process.
The first place where this process occurs, is the center of the star, because that's where the gravitational force power resides, and once the fusion starts the protostar becomes a star. and the star-to-be is a star. "Fresh graduate Star" Thank you all, now I really need a job. The star now started its new phase in life, and started using up its hydrogen in the process of nuclear fusion, it takes two hydrogen atoms and.... This hydrogen fusion produces huge amounts of helium and energy, and this energy is released in the form of light and heat.
Our sun remained in that state looking like a cloud, for almost 50 million years before reaching the nuclear fusion phase, which is the phase it's in now. Doesn't it emit light and heat? Then it's totally in fusion. It's in party mode. And it should remain fusing its hydrogen into helium and energy for 10 billion years, before its hydrogen is consumed. So enjoy your youth, sun. Today, we love the sun and what not but honestly we want to focus on a specific type of stars.
Its mass is at least 8 times more than the sun's. This type is a very cool one, and although it doesn't live long like our sun, just a few million years which is young in star-years, but because it's huge and greatly heavy, its gravitational force is enormous. It can merge three helium atoms together and form carbon! and take helium and merge it with carbon and produce oxygen! And oxygen with carbon producing silicon! Slow down, star, you're not John Cena. That's in addition to all the merges you can think of. Can you imagine the magnitude of such a star's gravitational force? It can merge chemical elements together and produce new chemical elements, only with the gravitational force! A gigantic and colossal force! You'll tell me, then what Abo Hmeed? For how long will we combine these elements? This massive star we're talking about will continue merging these different elements, until it produces iron atoms in the center of the star, and the iron element is known to be one of the hardest elements to be merged with another element, and it needs immense energy to fuse with another atom.
The problem is that the star's gigantic gravitational force, can't produce enough energy for iron to fuse with another atom. The iron produced is pressured more and more, so the center of the star, nucleus, starts getting hotter and hotter, until the iron cluster in the star's nucleus, reaches 1.4 of the sun's mass, or what's known as, the Chandrasekar Limit. God save us... It's really bad.
The nucleus then doesn't endure the pressure and extreme temperature, that can be up to a million degrees Celsius. My friend, the surface of the sun is only 6000 degrees, but the other star's center is a million! The nucleus then starts to collapse on itself, and explode in a massive and final burst of light and energy. This is the supernova, my friend.
The star is now dead. This is what Ibn Abi Usaybaa and Ibn Al-Diba'i saw...That's it. "The fresh graduate star's son": Thank you all...He was boiling. The huge explosion of the star, as we said, produces immense amounts of light and energy, and we can see it in broad daylight giving how strong it is, and it remains seen in the sky for days or even weeks, and at night could be brighter than some galaxies in the sky.
But in reality, there are other things that rapidly happen in the rest of the star, and they're all very extreme. In seconds after the explosion, the gigantic gravity in that star's nucleus, starts to compress it into a ball with a radius of 11km. Can you imagine this, my friend? A 2.8 million billion kg star
compressed in a ball with a radius of 11km! Shorter than the distance between Al-Zamalek and Heliopolis! With this mass ratio, you can compress the entire humanity to a size of a sugar cube. You would be taking a tablespoon of sugar for your tea, and its mass would be equal the mass of humanity! This tablespoon of sugar! Of course this gigantic density and the immense gravitational pressure, wouldn't just go by easily. The protons and electrons in the element's atoms are compressed in a tiny space...
What happens between them? Exactly, my friend! There will also be fusion! Just like the hydrogen. But this time, this fusion produces neutrons. And again this is only a nutshell. The idea is that what happens here is that protons and electrons fuse and produce neutrons.
And this births what's known as, the Neutron Star. A star made up of only neutrons, an extreme star, and add that it spins around itself in a greatly accelerated speed, and when I say great speed and extreme, then it's insanely fast! Because this neutron star spins around itself 38,000 times! One would tell me, So what, Abo Hmeed? 38,000 times in one year? In a day? Any Tanoura dancer would do it. Come here, you naive, it's 38,000 spins in one minute. -In what, Abo Hmeed? -In one minute.
-What, Abo Hmeed? -In one minute! I think it's hard for your Tanoura dancer. Don't be hasty, when I ask you something, it's a trap. In addition to that, these neutron stars feature having a magnetic field. And the least thing to say about this field that it's vigorous and powerful.
Because the weakest neutron star has a magnetic field bigger than the earth's! -How big, my friend? -I won't say, Abo Hmeed. Bravo. It's a 100 million times bigger.
Imagine the strength of the field! This magnetic field is strong enough to attract and accelerate particles that has electric charge and passing by. {\an5}"Magnetic field lines- Axis of rotation- Magnetic axis" and have them produce electromagnetic radiation, like the radio's. You know what revealed the neutron star? It wasn't known, but we discovered it through these radio-like waves. We're talking about a star of a diameter of 22km, and it's far in the sky, I can't see it. But when I find many radio waves coming, these are what made us discover the star.
Because again, it's too small compared to the other stars, we can't see it. After the supernova, it doesn't emit enough light to be seen. So the chance of seeing it in the sky is slim to none, almost impossible.
Despite that -I'm proud of the scientists-, the theoretical physicists predicted this neutron star since 1934! when Walter Baade and Fritz Zwicky, explained the supernova for the first time as we said. But the experimental astronomers discovered it more than 30 years later, when the colleague, Jocelyn Bell Burnell who was a PhD student in University of Cambridge in 1967, as she was in her office researching, she started noticing uniform, specific, and pulse-like radio waves, coming from somewhere in the sky. Of course, my friend, if you received radio waves and in the form of pulses, coming from outer space, having no explanation as a student, so she joked about it and said, that it's definitely from aliens, and called them little green men.
But after she directed the telescope to another area in the sky, she found the same uniform radio waves. Then she found another. Is there a party up there, guys? Anyway, after some research she published, along with her PhD mentor Antony Hewish, a research paper in January 1968 where they declare the discovery of the Pulsars, and the news started going around. Other astronomers started looking for these pulsars in other parts of the sky, and expected that these pulsars are the same as neutron stars created after the supernova. And that these radio waves, are the electromagnetic radiation it produces, due to the reaction of its strong magnetic field with the electric charged particles in space.
But because the star spins around itself these waves seem to us as pulses. And actually, if these pulses are simulated into sound waves, we'll hear this... It's as if you're standing on the beach in front of the sea at night and a lighthouse, the lighthouse's light doesn't turn off, but it keeps spinning around itself, so if you're standing far away and looking at the lighthouse, it'll seem as if it's turning on and off, that's why the star's radiation looks like pulses. The dear colleague, the Italian astronomer Franco Pacini, predicted a pulsing neutron star, in the location of the explosion of 1054's trail planet, that we talked about at the beginning. What's remaining of this great explosion now, is what's known as Crab Nebula.
If that explosion was indeed a supernova, then there's supposed to be a neutron star emitting radio waves, that reach us in the form of pulses as said by Jocelyn, and indeed, months after Pacini published his research, we traced uniform pulses of radio waves coming from the Crab Nebula, just like Pacini predicted! And that way, we had experimental evidence that prove the existence of neutron stars. Good job, Pacini. You might be wondering, my friend, why is the neutron star this important? is it your friend? and why is it important to look for the origins of the stars and all these astronomical phenomena? Look, my friend, you asking about why my topic is important means that you don't trust me. And we'll get back to that later. I only talk about important things, but the question is valid, and I'll address it. Humans are always curious to discover the world, and always have the motive to solve universe's mysteries, and their existential ideas.
One of these puzzling ideas, was the idea of time. More than 30,000 years ago, man used to observe the uniform motion of sun, moon, and stars in the sky. and realized things called time and space. Abstract things that you can't grab and put some in your pocket.
However, we can all feel them. We can measure them and know their quantities. For example, we could say that a day is a time period between two sunrises from the East. We could also say that it's a time period between two sunsets from the West. That specific time period could be too long for events that happen in a shorter time frame.
So, let's divide the day into 24 smaller units and call them hours. How do we measure them, Abo Hmeed? The simplest way to do so is by using the sundial. It tells you the time in hours using the moving shadow of a fixed object in direct sunlight.
What do we do at night, Abo Hmeed? There's no sun then. That means we need to make a more advanced clock. For example, we could make an hourglass. It's vessel that contains sand particles regularly flowing through a narrow neck by the force of gravity.
Or we can make a more complicated clock, like the beautiful elephant clock invented by al-Jazari in the 13th century, which doesn't only tell hours, but also minutes, using a complicated mechanism of consistent flowing of water inside the elephant. You might say: "I'm greedy, and I want measure time in units smaller than minutes." Cheeky! Then we could make a pendulum clock, which is operated by the consistent motion of a hanging pendulum.
It swings from right to left, and left to right in a boring and repetitive motion. However, we can use it to measure smaller units like seconds. Have you noticed something? All the devices and clocks we use to measure time depend on a consistent change in something. That consistent change could be moving sunlight, or a swinging pendulum, or dripping water. We even started to invent more accurate clocks using a consistent flow of a certain amount of electricity, like the digital watches we wear. So, in any clock, no matter it's mechanism, depends fundamentally on measuring a consistent change that happens consistently and frequently over time.
When we study the sky, the stars, space and galaxies, we discover that our devices and methods to measure time are not suitable, nor enough, nor accurate. You know what? Same as our methods to measure distance as well. -We are so bad at this, Abo Hmeed. -Yep.
Hey, Abo Hmeed, You keep knocking the fundamentals, It's not a boxing match. How old am I? I'm confused! Wait, my friend, just wait. Because time and space on this astronomical level is considered a single unit called space-time. Life up there is larger and wider than anything anyone could ever imagine. Literally and figuratively. We need more complicated measurement tools and technologies.
The pulsar neutron stars that we talked about are currently considered one of the most accurate ways to measure time. Considering it's very consistent pulsating radiation. That means we can use them as an accurate clock in space. We do need them to measure cosmic distances between celestial bodies. We also need them to measure the expansion of the universe over time.
We need them in research fields, like research for Dark matter, dark energy, and gravity waves. We have a number of astronomical research fields that depend somehow on pulsars. So, it's very important to know more about these stars, and the differences between them.
Because a neutron star in some region can't replace another in a different region. That in and of itself is a big research field astronomers are still working on. For example, which pulsars can we use as cosmic clocks while studying gravity waves? That specific question was answered by the Egyptian astronomer Maryam Haytham Esmat, who classified in her research about pulsar neutron stars in 2021 424 pulsar stars out of 13522 that we can actually use to detect gravity waves, like the LISA space probe. That will hopefully launch in 2034. However, until 2034 is here, you should probe the old episodes, the new ones, look at the sources, and subscribe if you're on YouTube.
subscribe, my friend! That's it. Watch yourself stars. Stop flirting with people in collage, sending messages and stuff. Be straight forward, ok? Unbelievable.
2023-03-02