Did you know that there is a giant spacecraft that has been hovering around the Earth’s orbit since November 1998? This magnificent spacecraft is home to the best crew of astronauts and astrophysicists from around the world. It is a unique laboratory equipped with the best-in-class equipment built to study the nature of space, analyze the behavior of the human body when exposed to prolonged stays in space, and research various phenomena occurring in and around our planet. It orbits the Earth at a whopping speed of 17,500 mph, at that speed, it takes only 90 minutes to orbit the entire planet.
Origins
In November 1998, the first component of ISS was launched from a Russian Proton rocket from Bikonur Cosmodrome in Kazakhstan. With the combined efforts of the best astrophysicists and scientists from around the globe, the ISS was assembled over the next two years with increased precision and attention to detail. The first crew made it to the space station on November 2, 2000, and the initial stages of the research began in full swing. Eventually, NASA continued to add different sections to the space station with the help of Russia, Japan, and Europe, thereby completing the construction in 2011.
What Is In The ISS?
Weighing close to one million pounds under the Earth’s gravity, ISS can support a crew of six astronauts and a few visitors from Earth. It is a large facility that covers the size of a football field with five separate sectors for astronauts from Russia, Japan, United States, and Europe.
ISS consists of labs that enable astronauts to conduct scientific research, modules that are home to systems that enable the space station to function, living areas for the crew, and nodes (modules) that connect parts of the space station with each other. It also consists of solar arrays or solar panels on its sides that collect energy from the sun in order to enable optimal functioning.
Also, robotic arms are mounted outside the space station enabling radiators to control the temperature. These arms also aid astronauts to perform routine maintenance procedures of the space station in hard-to-reach areas. They also move astronauts around when they are out for spacewalks outside.
ISS is also equipped with an airlock sector that is open to the outside enabling astronauts to go on spacewalks with ease. It is an airtight room with two entrances that opens without letting air out of the spacecraft. It also acts as a docking port for new visitors to enter and receive supplies for the crew from Earth.
Why Is ISS Important?
ISS has enabled humans to live in space and explore various aspects of how the human body behaves when exposed to microgravity (the condition of being weightless). For over 20 years, astronauts have been living in space laboratories and performing in-depth research on aspects that cannot be done on Earth. The behavior of liquids, and gases under microgravity, have been clearly analyzed. It allows scientists to understand the mechanism of spacecraft when on a long-term space journey. This station has provided a perfect platform to prepare astronauts for long-term space travel and is currently being used to study the travel from Earth to Mars. It enables humans to reach the farthest points in space than ever before.
I am sure that there has been a time in your life when you looked up at the stars in the night sky and thought to yourself. Hmm, I wonder what makes them shine so brightly? There must be some secret behind it. Well, it’s no secret; it’s science! For centuries, stars have been used widely in poetry, essay, children’s rhymes, and lullabies. We have always gazed up at the night sky and tried to identify the constellations. Oftentimes, we are able to identify some prominent stars which are closer to Earth as they usually shine brighter. Let us now delve deeper into the cosmos and understand how these wonderful twinklers get their shine.
How are Stars Born, and what are they made of?
Stars are massive gas giants, not the ones like Jupiter but the ones which are way more massive than Jupiter. Did you know that it requires the mass of 70 Jupiter-sized planets to form the smallest star? 70 Jupiter-sized planets are the smallest amount of material that is enough to trigger nuclear fusion to qualify as a star. This type of star is known as a red dwarf. To understand the principle of star formation, we first need to understand the key concepts of nuclear fusion [1], nebula, and the influence of gases like Hydrogen, Helium, and oxygen.
Nebula
A nebula is a large accumulation of gas and dust in the fabric of space. Gravity influences this nebula, and the gas and dust begin to shrink and divide into small balls which look like swirling clumps. When each clump becomes ball-shaped, they continue to shrink the material, which begins getting hotter. Once the temperature reaches 10 million degrees centigrade (1 crore), an explosion would occur, thereby resulting in a nuclear fusion. When this fission starts consequently, and at a large scale, a new star is born. There are other ways how a star can be born; one such way is through a supernova explosion (which will be covered in this article), where the death of a massive star gives rise to a new high-density star known as a neutron star.
The Life of a Star
Learning the life of a star would be quite interesting as it delves into various aspects which could broaden the perspective that you have about our universe. It will also help you see our Sun in a new light and understand how its life was and will come to be in the distant future. The life span of a medium-sized star such as our Sun is around 5 billion (500 crores) years. Larger stars would have shorter lifespans; this is because their energy would burn out quicker. Similarly, stars that are smaller than our Sun tend to last longer. Have you ever wondered why stars don’t seem to change at all? A star would look the same to you now just as how you had observed it when you were five years old. This is because your lifespan would be like a second to that of the lifespan of a star.
The Birth of a Star
Not all stars follow the same path; their path would depend on the mass of the star or how much gas was collected and collapsed to form that star. This gas would serve as fuel for the star. In a nebula, when nuclei of an atom collide with enough energy, there would be a large electromagnetic repulsion between them. The strong nuclear force would take over, and the nuclei would fuse, with a small fraction of their mass converting into energy. Only when nuclei collide and fuse into the core of a star will they release enough energy to counteract the gravity crushing inward. The matter that forms a star determines the amount of fuel. With a variety of other factors, the lifetime of a star can be determined.
As we now know that any star begins from a large cloud of gas and dust; this material needs to be at least a few lightyears across. During the earliest era of star formation, this material would exclusively be Hydrogen and Helium. This was what existed in the brief 17 minutes after the big bang nucleosynthesis [2]. Hydrogen and Helium collect due to gravity and push inwards as it contracts. In this process, immense heat is generated, resulting in a nuclear fusion. This entire process is not immediate as it occurs over a few million years. A yellow or red main sequence star will be born in the process of the fusion reaction, and the glow will be the result of this reaction happening in a nearly endless cycle.
The Red Giant Phase
As long as there is hydrogen to fuel the nuclear fusion reaction, the star will continue to shine over a few billion years, depending on the mass of the star. Once the hydrogen fuel begins to deplete, the core of the star will slowly begin shrinking. When the core starts to shrink, it will become much hotter, resulting in the hydrogen fuel burning faster. The fast-burning fuel will result in extra energy released by the reaction, which radiates outwards, resulting in the outer layers of the star being pushed away from the core. This process would result in the star’s outer layers expanding, making it appear like a red giant. When the outer layer cools, the star becomes red. The star will continue to expand until most of the residual fuel is burnt. A star like our Sun will reach this stage of the life cycle around 5 billion years from now. At present, our Sun has already lived 50% of its life. A star will typically stay a red giant for around a billion years.
A Red Giant
White Dwarf- The Death of a Star
Yes, even stars die out eventually, but they would have lived a glorious life of 10 billion years (1000 crore) before they die out (This is for a medium-sized star such as our Sun). After all the reserve hydrogen fuel in the star depletes, the core begins to get even smaller and even hotter. This results in a helium flash phase. Wherein the star becomes so hot that it begins fusing heavier helium nuclei into larger nuclei through a process known as triple alpha. This means that the star has a whole new fuel other than the one that it burns for billions of years. This results in the star starting to pulsate as it runs to the final energy fuel. At this point, the star starts to contract and becomes smaller, hotter, and appears blue as most of the Helium has fused into larger nuclei. The core then becomes mostly carbon and oxygen, with a shell of Helium and hydrogen around it.
At this phase, the star has very little material left to burn, and the core will collapse. This results in the star expanding to a red giant once again until its last bursts of energy eject the outer shell. Once the outer layer of the star dissipates, only the core, which is roughly the size of our Earth, will remain. This core will gradually cool due to a lack of fuel to burn as it is not hot enough to fuse carbon or oxygen nuclei. This results in the core contracting further until the star appears to be white, earning the name “white dwarf.” This white dwarf phase would last for 10s or 100 billion years until eventually further cooling and becoming a black dwarf. At present, there are around 8 white dwarf stars discovered among hundred-star systems that are closest to our Sun. There are no known black dwarfs in our universe, as it would take trillions of years for a white dwarf to reach that stage, and our universe is just 13.8 billion years old.
A white dwarf
Planetary Nebula- The Circle of Life
Now that we have covered the life cycle of a star let us understand a few things that influence the birth and death of stars. During the red giant phase of a dying star, the shell that ejects from the core is known as a planetary nebula. The name could be misleading as it didn’t appear from a planet; it was because there was confusion during its discovery. A planetary nebula comprises large gas and dust particles, which are nothing but the remnants of a dead star. This gas and dust will become available to join another nebula in the vast universe and form yet another star.
Planetary nebula
What Happens to Larger Stars?
A star that is over 15 times the mass of our Sun is known as a high-mass star. These stars have much shorter lifespans ranging between 100 million years to even 10 million years. As mentioned before, the larger the star, the shorter its lifespan. High-mass stars usually die out with a bang, which is known as a supernova. Larger stars are formed by larger gas clouds contributing to more mass, which implies more gravity. In these starts, the force pushing inward will be much stronger, resulting in the star being much hotter. This results in faster fusion, generating a great outer pressure to counteract the inward pull of gravity. This type of star is known as the main sequence star, which appears big bright, and blue.
During the last stage of the main sequence star, the fuel runs out, and the core contracts and heats. This results in the star becoming a giant star, as in the case of low and medium-sized stars. However, when the core of a high-mass star begins to compress, it becomes much hotter than a star the size of our Sun. When the core compresses, it forms not only Helium, Carbon, and Oxygen but also Neon and Silicon. These layers are separate and pushed down on the super-hot core, which turns the core into iron. Each layer performs a particular type of fusion until no fuel remains.
A Supernova Explosion Occurs
The core of the star comprises iron nuclei which are so stable that further fusion would release no more energy. When this occurs, gravity wins the fight as there is no longer enough fusion reaction to counteract the force of gravity. All of the outer layers bounce off the core in a single second, resulting in a large massive explosion ejecting all the heavy nuclei and the remaining fuel into outer space. This explosion is what is known as a supernova. Here is a better way to understand it, if you compress an object like a small iron ball or marble using a hydraulic press, the marble ball would eventually explode due to the pressure leaving dust and debris. This is the force of compression at a small level, but the compression that triggers a supernova explosion is much higher.
Artist’s depiction of a supernova
A supernova explosion is known to be the most violent and energetic phenomenon in the universe. The explosion would be brighter than the entire galaxy that they belong to. It is so bright that its glow would be visible through the naked eye even if you are hundreds of lightyears[3] away from the explosion.
The explosion of a supernova does not leave behind a white dwarf star, unlike low-density stars. If the core of the star before the explosion was between 1.4 or 3 solar masses, the core would not be able to support itself against gravity and will collapse. This collapse will be so powerful that all the electrons will squeeze into protons such that they combine to form neutrons. The shockwave from this event is the supernova. The remnants would be a ball of neutrons bunched up together, which make a large atomic nucleus the size of 20 km in diameter. This resulting core would be so dense that a teaspoon from it would weigh a whopping 10 million (1 crore) tonnes. This core is what is known as a neutron star.
If the core of the resulting neutron star from the supernova is above 3 solar masses, the outward pressure of neutrons pressing against each other (neutron degeneracy pressure) will result in neutrons being crushed together to a single point of infinite density. This single point of density is what is known as a black hole.
Conclusion
Now that we have learned the lifecycle of a star and the birth and death of stars, I will be covering the types of stars in my upcoming articles. Scientists are still on the road to researching different types of stars and are on the verge of discovering new principles that would influence future events in our galaxy. We are still in the infancy stage, and there is a lot more to understand about stars. Now you can gaze at the night sky, knowing how these wonderful twinklers came to life and how they would die. It’s all a circle of life; when one star dies, its remnants (planetary nebula) will influence the birth of another beautiful star.
Glossary
[1] Nuclear fusion– Nuclear fusion occurs when two large nuclei in an atom merge together to form a larger, heavier nucleus. In this process, a lot of energy is released as the overall mass of the resulting nucleus is less than that of the two original nuclei. This leftover mass translates into energy.
[2] Nucleosynthesis- The creation of atomic nuclei at the center of atoms which comprise protons and neutrons. This process occurred within the first few minutes of the big bang.
[3] Lightyear- Distance traveled by light in one year
Jayshree was on her way back from work after a long shift. As she was walking back home, she looked up at the sky and noticed a jet aircraft speeding upward leaving a long stream of smoke in the process. She went into deep thought and wondered how aircraft and rockets are able to produce enough energy that enables them to soar high into the sky and leave the Earth’s atmosphere. She pulled out her smartphone, opened YouTube, and began watching videos explaining rocket propulsion. However, to her dismay, none of those videos seem to explain the concept clearly. That’s when it struck her, what’s better than to ask her boyfriend, Rupesh, who worked at the ISRO space station at Sriharikota as a senior engineer.
When Jayshree reached home, she took a bath and prepared Dosa and Kadai mutton gravy. She finished dinner and decided to call Rupesh and ask him about the question which has been eating her head for the past few hours. She opened Google Keep on her tab to take notes and called her boyfriend.
“Hi babe, how was your day sweetie? I hope all is going well.”
“Everything is going just fine babe, it has been a rough day at work today, as the Chief of Defence visited the ISRO station. We had to keep everything in check and ensure that they were all in order.”
“Oh I see, I hope you are less stressed out now, cause I really need you to explain to me about the science of rocket propulsion.”
“Wow Jayshree, I thought you were not much into the stuff that I do. Anyways, I am all fine and am ready to explain to you, babe.”
Rupesh was quite excited to see that his girlfriend had gained a sudden interest in his line of work and most importantly, was eager to know about rocket propulsion.
What is Rocket Propulsion?
Rupesh cleared his throat and began the lesson, “Just like how you light up a firework during Diwali, rockets work in a similar mechanism to that but with a lot more changes with regards to fuel, combustion method, and other related principles. Let us delve into these concepts step by step.”
“Newton’s third law of motion plays a pivotal role in understanding the principle of rocket propulsion. This states that force exists in pairs. Let’s say an object A exerts force FA on another object which is B. Then B simultaneously exerts a force FB on A, with two forces being equal and opposite. FA= -FB. There are three key factors which contribute to the rocket’s acceleration which are, the rocket’s mass, the exhaust velocity, and the rate at which the exhaust is ejected.”
“In order for a rocket to escape Earth’s gravity, the exhaust velocity needs to be proportional to the gravity of Earth. In other words, the velocity and force exerted by the exhaust need to be powerful enough to counter the gravity of Earth. The force used by the rocket is driven by the fuel which is combusted and forcefully ejected from the exhaust that an equal and opposite reaction occurs.”
“Hmm, I see so that’s how the theory of rocket propulsion plays in. Now can you please elaborate on the components of a rocket?” Asked Jayshree.
Rocket Propellent and its Types
“Jayashree, there are two main types of rocket propellants used in rockets. One is the liquid propellant and the other is a solid propellant. A rocket that is powered by a liquid propellant contains liquid fuel such as liquid oxygen, liquid nitrogen, and an oxidizer. The liquid oxidizer is present on top, with the fuel tank below it, and the pumps, which are below that. The pumps are responsible to carry the fuel and the oxidizer to the combustion chamber, which is right below the exhaust. Since there is no oxygen in outer space, rockets need a liquid oxidizer to ensure combustion as fire cannot burn without oxygen. Liquid propellant-powered rockets are mainly used on space shuttles and unmanned missiles to place satellites in orbit.”
“You have explained it so clearly Rupesh, can you tell me about solid propellant rockets?”
“Of course, Jayshree, you see, solid propellant rockets mainly comprise of two components, which are the solid oxidizer and the solid fuel. The solid fuel oxidizer is a mixture of ammonium nitrate and ammonium dinitramide, which is present in a cylindrical hole in the middle of the rocket. The igniter is used to combust the propellant surface and the hole in the middle acts as the combustion chamber. These rockets comprise a hot exhaust choke which is also found in automobiles. This hot exhaust is choked and the exhaust is expelled from the exit.”
Rocket propulsion types
Rupesh continued, “Now that you have learned about the principle of rocket propulsion and the types of rockets, you need to understand what are the factors which influence the rocket’s acceleration Jayashree. You see, the acceleration of the rocket will be greater with the exhaust velocity of the gases being greater than the rocket. Also, the acceleration is greater if the fuel in the rocket burns faster. As the mass of the rocket decreases, the acceleration will be greater, that’s why rockets tend to go faster as they reach the outer layers of the Earth’s atmosphere. This is because half of the fuel would have got burnt, thereby reducing the mass of the rocket.”
Conclusion
“Thanks, Rupesh, you are such a charmer, no wonder I fell for a rocket enthusiast like you. I am so glad that you took the time to explain this, you made complex rocket science seem like a walk in the park.”
“The pleasure is mine babe, I would love for you to visit Sriharikota sometime, I would give you a full-on tour of the place.”
“That would be awesome babe, now that my newfound interest is about science, I would love to visit ISRO soon. Let our next date be amongst large rockets ready to leave the Earth.”
“Absolutely Jayashree, I would love that. And also, always remember, there is always a lot of research going on in the field of rocket science. Did you know that scientists like us are working towards finding different propulsion systems and nuclear-powered rockets? Fossil fuels are going to go extinct in a couple of decades and we need to find new ways to reach outer space.”
The law of conservation of energy is one of Newton’s primary laws, which states that energy can neither be created nor destroyed. Schrodinger’s equation plays the role of Newton’s laws and conservation of energy by predicting the future behavior of a dynamic system. It clears the air and clarifies the crux of the conservation of energy aspect. The equation is a wave function that predicts the probability of events or outcomes. The detailed outcome is not strictly determined; however, Schrodinger’s equation is widely used to predict the distribution of results.
Who is Schrodinger?
Erwin Schrodinger was an Austrian theoretical physicist who contributed to the wave theory of matter and other aspects of quantum mechanics. For his wide array of contributions, he was awarded the Nobel prize for his contributions in 1933, which was shared by another British physicist.
Schrodinger obtained his doctorate from the University of Vienna in 1906, which helped him to accept a research post at the university’s second physics institute. He served the military in World War one and went to the University of Zurich in 1921. He was such a determined person that he published papers that paved the foundations of quantum wave mechanics well past his retirement. In his work, he described the partial differential equation that has a relationship between the equation of quantum mechanics and mechanics of the atom.
A Quick Brush up
Through the work of Albert Einstein and Max Plank, we have learnt that energy is quantized, and light exhibits wave-particle duality. Quantized energy means that the system can have only certain energies and not a continuum of energies. For instance, only certain speeds at which a car can travel due to its kinetic energy could be having only certain values. Physicist Louis de Broglie extended this duality to include matter, which is that all matter possesses a wavelength. Regardless of it being a tiny electron, a whole body, or a huge star.
An object’s wavelength is inversely proportional to its mass, which means that macroscopic objects have very tiny wavelengths. However, since an electron is so small, its wavelength becomes relevant, which is being around the size of an atom. Therefore, we can conclude that electrons can behave like waves and particles.
Wave-nature of an Electron
An electron can be regarded as a standing wave but not a linear wave. It is a circular standing wave that surrounds the nucleus. This helps us understand why the quantization of the energy of the electron is clear. This is because any circular standing wave can only have an integer number of wavelengths. With the increasing number of wavelengths, more energy will be carried by the wave. An electron in an atom can only have a discreet number set of energy levels.
When an electron strikes a proton of a particular energy, this energy is absorbed, promoting the electron to a higher energy state and increasing the number of wavelengths—contained within the standing wave.
Here, the constructive equivalence of standing waves results in covalent bonding through orbital overlap. When it was realized that electrons exhibit wave behavior, physicists were keen on finding a mathematical model that describes this behavior. In 1925, Erwin Schrodinger achieved this goal with his signature equation.
The Schrodinger’s Equation
Schrodinger’s equation is a differential equation that is hard to decipher and cannot be explained in this article as it contains arithmetic. However, let us look into the conceptual aspect of this equation. Just like how Newton’s second law states that force equals mass into acceleration, the Schrodinger equation is applicable to quantum systems by describing a system’s three-dimensional wave function, which is represented by psi.
H represents the Hamiltonian operator, a set of operations that describe all interactions that impact the system’s state. This refers to the total energy of a particle. Although this calculates the wave function, it doesn’t describe what the wave function is. Physicist Max Born proposed that the wave function has to be interpreted as a probability amplitude. The symbol Ψ tells the probability of an electron found in a particular spot.
In the double-slit experiment, the diffraction pattern illustrates the wave of probability clearly. This pattern illustrates the probability of an electron arriving at any given spot. Bear in mind that the exact location of where an electron will land cannot be predicted; only the probability of arrival at a location can be deciphered. If many electrons arrive, it is apparent that their distribution obeys the wave function.
Schrodinger’s equation computes the wave function deterministically, but the information it contains is probabilistic. This concept of the probabilistic nature of computation was a lot to handle for the scientific community to handle and still continues to be. Just like how sound waves are oscillations in an electromagnetic field, and sound waves are mechanical waves, an electron can be considered as clouds of probability density.
Interpretations of Quantum Mechanics
Schrodinger conceived this equation that helped in interpreting some concepts in quantum mechanics. There were many other physicists who interpreted quantum mechanics, some of which include Copenhagen Interpretation, many-worlds interpretation, Quantum decoherence, and Bohmian Mechanics. These interpretations are different ways of relating the wave function to experimental results and the fundamental beliefs about nature.
Conclusion
The development of quantum mechanics has surely come a long way since Schrodinger’s time, and the recent developments have made a big change in today’s scientific community. Schrodinger’s equation has paved the way for physicists to delve deeper into quantum mechanics and particle physics. Scientists can decipher the interactions of various types of particle matter and compound elements through extensive research.
Have you ever wondered how the continents in our world took shape? Did you know that over 250 million years ago, the world was comprised of only one large landmass surrounded by a massive ocean? The first-ever landmasses took hundreds of millions of years to form. This was after the Earth cooled and the atmosphere was formed, over 3 billion years ago.
Our Earth has been through hell, taken a severe beating from various external forces, and sacrificed a lot to make life possible for millions of species that thrive today! The movement of tectonic plates is the reason why we see the continents that are present today. Tectonic plates comprise the Earth’s uppermost mantle and comprise oceanic and continental crusts. Earthquakes typically occur around mid-ocean ridges and large faults that mark the edge of plates.
Tectonic plates constantly move even today; that’s the reason why tsunamis and earthquakes occur. The continents which we see today are the result of a 250-million-year-old journey of plate movement. Come, let’s dive into understanding how the movement of plate tectonics have shaped the continents we see today.
Super Continent Pangea
Around 300 to 275 million years ago, a supercontinent called Pangea existed, which was known to be the first-ever landmass to exist. This amazing supercontinent was surrounded by a massive ocean called Panthalassa. Pangea existed during early the Permian period when the first multi-cellular organisms thrived on Earth. Plants, insects, vertebrate animals and early marine life lived during the Permian period.
After studying the geological composition of Earth in 1912, Alfred Wegner, a German meteorologist, proposed the existence of Pangea as a part of his theory of continental drift. Later, geologists further delved into this theory, studied the composition of the Earth’s crust and the movement of plates to confirm the existence of this supercontinent. Pangea in Greek means “all the Earth.”
Continental Plates
The continents we see today are the product of over 250 million years of tectonic plate activity. Pangea began to break apart around 200 years ago during the Early Jurassic Epoch. This supercontinent broke and drifted apart in different directions. Each continent is placed on a specific plate. Some important plates include South American Plate, Eurasian Plate, Indo-Australian plate, North American Plate, Caribbean plate, and Antarctica plate.
Formation of Continents
When Pangea first broke apart, each continental plate broke apart, and the respective plates began moving in different directions according to the movement of the tectonic plates. Another important point to note is that in some cases, the movement of the tectonic plates were accelerated by strong oceanic currents.
The North American plate was the first to break apart and moved in the north-western direction. Another large chunk of landmass at the bottom of Pangea broke off and moved southwards to form Antarctica. The Indo-Australian Plate, stuck to the Antarctic plate, broke apart and moved eastwards with a slight tilt towards the north. The Eurasian plate began moving in the North-East direction. The South American plate began moving towards the west, and the African Plate began moving towards northwards, eventually touching the Eurasian Plate. All these continents moved to their current location over 200 million years.
Formation of the Himalayas
Now that we have seen how the movement of plate tectonics has shaped the continents we see today. You might be wondering, isn’t there something that I have missed out on? Yes, how could one forget about the Indian sub-continent? Well, the best has been saved for the last.
Around 200 million years ago, the tectonic plate that holds the Indian Subcontinent was located in the southernmost region of Pangea right above Antarctica. This plate was sandwiched between the African plate and the Indo-Australian plate. Initially, the African and the Indo-Australian plates broke apart. After another 10 million years, the Indian Subcontinent broke away from the Antarctic Subcontinent and began moving northwards towards Asia.
The plate that held the Indian Subcontinent moved relatively fast. Most of the crust below the Indian Subcontinent came off due to the movement of the oceanic plate, thereby making the landmass much lighter. With excess weight shed off, the Indian Subcontinent travelled relatively faster over millions of years from the region close to Antarctica to Asia. During the initial stage of the journey, a small landmass in the western side of the Indian Subcontinent broke apart and moved along the African plate. This landmass is what is now known as Madagascar.
The Indian Subcontinent made contact with the Eurasian plate around 50 million years ago. The impact of this collision is what caused the formation of the Himalayas. When the Subcontinent collided, the oceanic plate that was attached to the North-East portion of the landmass made contact with the Eurasian plate. This collision lifted the plates to form the Himalayas. Even today, the Indian Subcontinent continues to move Northward by a small margin, causing earthquakes in Nepal and parts of Tibet.
Conclusion
Tectonic plates are constantly moving, and in a few million years into the future, the continents we see today will eventually drift further away. Who knows?? Maybe 200 million years into the future, all continents may even converge together and form a new landmass.
How did the universe begin? This question has been a matter of debate between scientists and religious leaders from time immemorial. The creationists would go on to argue that an almighty supernatural force called “God” was the reason why this universe exists. Well, that is absolute humbug, as any rational person with an iota of logic would look for a scientific explanation with proof and observation of how the universe formed.
Telescopes, rockets, and modern science have now improved to a great extent, enabling scientists to decipher the mysteries of the universe and gain a better understanding of them. This is bad news for religious leaders as they would find it harder to convince believers due to concrete evidence that contradicts their teachings. Besides, with modern science advancing at a rapid pace, why follow a 2000 year old religious book that is currently obselete.
Scientists have been racking their brains on how the universe began for centuries. Until the 20th century, they thought that the universe was infinite and ageless. However, with the advent of Einstein’s theory of relativity and the launch of the Hubble Space Telescope, we are able to understand the nature of gravity and that galaxies are moving apart from one another.
The Big-Bang Theory
In 1964, scientists discovered cosmic background radiation, which is like a relic of the early universe. This discovery and other observational evidence made the big bang theory the most acceptable theory in science. The Hubble space telescope gave a clear view of the structure of the cosmos, with recent theories suggesting that the universe is continuously expanding.
13.8 billion years ago, the big bang occurred. During the big bang, the physics laws we know would make no sense, and time would behave haphazardly. To further understand this, there has to be a theory that unifies Einstein’s theory of relativity and quantum mechanics, which countless scientists are working on. Scientists to this day have no proof of what triggered the big bang or whether it occurred naturally. They also don’t know whether the big bang was a result of the death of another universe after the big crunch, which resulted in the birth of a new universe.
The Explosion
The big bang theory states that an extremely dense point in space exploded in an unmeasurable force that resulted in space stretching everywhere all at once. The universe did not expand into anything, but space was expanding into itself. This is because the universe cannot expand into anything as it lacks borders. There is no such thing as outside the universe, as the universe is all there is.
During the expansion of space, the early universe comprised a hot dense environment that was uninhabitable. Here, energy manifested itself in tiny particles that existed for a very small point in time. Quark is an elementary particle that forms the fundamental constituent of matter. Gluons are also elementary particles that act as a strong exchange particle for the strong force between quarks. A pair of Quarks was created from Gluons, which destroyed one another or even gave off more gluons. These Gluons found other short-lived Quarks to interact with, thereby forming new quark pairs and gluons. Here, matter and energy were not equivalent as the temperatures were so hot that both were the same stuff.
Natural Laws Came into Play
Matter won over anti-matter in a battle. This is why the universe is now filled with matter. Instead of one strong force that monopolized the entire universe, several refined versions of it began acting under separate rules. The prime forces being strong nuclear force, electromagnetic force, weak nuclear force, and gravity.
With the universe stretching to a billion kilometres in diameter, the temperature decreased to a great extent. Now, the cycle of quarks that were born and being converted back to energy broke apart. Quarks began forming particles like protons, electrons, and hadrons, with several combinations of quarks forming into all types of hadrons. However, only a few remained stable for any length of time. Due to the universe cooling down considerably, neutrons decayed into protons to form the first atom, Hydrogen.
Formation of Stars and Galaxies
The universe was now around ten billion degrees Celsius, full of countless particles and energy. Atoms formed out of hadrons and electrons, giving rise to an electrically neutral environment. This period was known as the dark age due to the presence of no stars. Hydrogen gas did not allow visible light to move around, causing it to clump together. After millions of years, gravity began pulling it under great pressure, with stars and galaxies beginning to form. Due to the radiation, stable hydrogen gas dissolved into plasma that permeates the universe today, allowing light to pass. This whole process resulted in the universe that we see and experience today.
What would happen if a star with over 10 to 25 times the mass of our Sun goes supernova? There are two probabilities due to the resulting supernova explosion; one would lead to forming a black hole, and the other leading to the formation of Neutron stars. With the most powerful gravitational field and magnetic force, Neutron stars are spinning balls of collapsed stars that illuminate the night sky. Astronomers have discovered nearly 2000 Neutron stars in the milky way and theorize that there could be over 1 million in our neighbouring galaxies.
How is a Neutron Star Formed?
In our universe, new stars are formed from the remnants of collapsed stars. The same is true in the case of a Neutron star. Before understanding how Neutron stars were formed, we need to know a little about stars and the cause of a gravitational collapse. Stars comprise millions and billions of hot plasma that is being pushed into the core due to gravity that nuclei fuse. Hydrogen fuses into Helium, thereby releasing energy that pushes against gravity and tries to escape. Stars are quite stable as long as this balance exists. However, over a few billion years, this Helium will get depleted and result in the star growing into a red giant. Medium-sized stars like our Sun will burn Helium into Carbon and Oxygen during the end of their life, swelling into a red giant. These medium-sized stars will turn into white dwarfs.
Gravitational Collapse Resulting in a Supernova
However, for stars that are 10 to 25 times the mass of our Sun, the internal reaction would be far different once the Helium gets exhausted. The balance of pressure and radiation collapses, and gravity will squeeze the star tighter, and the core would burn hotter and faster, resulting in the star swelling hundreds of times. At this stage, heavier elements will begin to fuse; carbon burns to neon in a few centuries. Neon burns to Oxygen in a few months, Oxygen burns to Silicon in months, and Silicon burns to Iron. This Iron ball is nuclear ash with no energy to give and therefore cannot be fused. Without the outward pressure from fusion, the core gets crushed due to the enormous weight around it.
Due to the collapsing weight of the star, the electrons and protons fuse into neutrons and further gets squeezed together. This is known as a gradual gravitational collapse. Here, an iron ball the size of the Earth gets crushed into a small ball the size of a city. This will result in the whole star imploding with gravity, pulling the outer layers of the star at 25% the speed of light. This implosion bounces off the iron core, producing a massive shockwave with the remnants of the star spewed into space. This is known as a supernova explosion, which is so bright that it could outshine galaxies. After the explosion, what remains is a Neutron star with the mass of over a million Earths but compressed to an object which is nearly 25 km wide.
The Nature of a Neutron Star
A Neutron Star’s gravity is the second strongest in the universe, first to black holes. If a Neutron star gets denser, it could even become a black hole. Even light gets bent around it, so you can only see the front and parts of the back. They are massively hot as they burn at a million-degree Celsius. Just like planets, Neutron stars also comprise an atmosphere, crust, and core. The crust is very hard as the outermost layers comprise iron leftover from the supernova explosion. On the crust, there are enormous nuclei with millions of protons and neutrons shaped like spaghetti. Physicists call this nuclear pasta which is known to be one of the densest and strongest materials in the universe. Nobody knows what the core of a neutron star might comprise due to its dense nature. Physicists theorize that protons and neutrons might dissolve into an ocean of quarks known as the Quark-Gluon plasma.
Celestial Ballerinas
Have you ever seen a ballerina spinning by pulling her arms in? When Neutron stars collapse, they begin spinning very fast, several times per second. PSR J1748-2446ad is one of the fastest spinning neutron stars in our universe, spinning at 716 times a second, which is nearly 25% the speed of light.
The spin of Neutron stars creates radio pulses that can be detected. These are known as radio pulsars, which are the best-known type of neutron stars. These fast-spinning celestial ballerinas are known as magnetars until they calm down. Magnetars are 1000 times stronger than regular neutron stars, with a magnetic field that is 100 million times stronger than the most powerful man-made magnets.
The Collision of Two Neutron Stars Forms a Black Hole
The best types of Neutron stars are friends with other neutron stars. While radiating energy like gravitational waves and ripples in space-time, two Neutron stars would collide as their orbits decay. Their collision would result in both stars getting destroyed in a killonova explosion, forming a black hole. The remnants of the explosion and debris of a killonova explosion will mix back into the galaxy. Some of them end up in a cloud that gravity pulls together, leading to the formation of stars and planets. This process would repeat as a cycle.
Even our solar system is the product of the remains of collapsed Neutron stars. In fact, all the elements in our technological world are built out of the elements Neutron stars made billions of years ago.
Monica was an inquisitive fifteen-year-old girl who was always in the pursuit of learning more and experimenting with various concepts. She was a very bold teen who never backed down to a challenge and always questioned age-old beliefs and primitive religious ideologies. On a fine Saturday afternoon, Monica finished her assignment that encompassed the core concepts of Einstein’s theory of relativity. She was fascinated by the theory of interstellar travel through Einstein’s Rosen Bridge, popularly known as wormholes. She wanted to know more about this concept, so she turned to her father for an explanation.
Monica’s father, Richard, was a theoretical astrophysics and cosmologist who often kindled Monica’s interest in Physics and Astronomy. He always made it a point to address his daughter’s queries patiently despite his busy schedule.
What are Wormholes?
Monica asked, “Hey dad, I have been looking into the concept of Einstein’s Rosen Bridge but couldn’t make heads or tails of it! Can you please explain?”
Richard replied with a sparkle of excitement in his eyes, “Wow, Monica, I am so glad that you are interested to learn more about this wonderful theory. It would be a pleasure for me to explain this to you.”
He continued, “Monica, to understand the theory about wormholes, you need first to know Einstein’s theory of general relativity and its relevance to the Rosen Bridge. Since general relativity states that the region of space and time can be bent and is not static, Einstein and physicist Nathan Rosan further elaborated on the idea. They proposed the existence of space-time through bridges that connect two different points in space-time. This bridge was coined as the Einstein Rosen bridge.”
“I understood the concept of the bridge, dad. Can you elaborate on the use of this bridge?” Asked Monica.
“Sure honey, since these bridges connect two different points in space-time, it could reduce the travel time drastically. If you are looking to travel to a place that is several lightyears away, wormholes can make your journey much faster.”
Monica asked, “But dad, don’t the laws of physics state that no object of mass can travel at or faster than the speed of light?”
“Yes, that’s right, dear, but when it comes to the concept of wormholes, it establishes a portal that directly ships you to another point in space-time in an instant. It is kind of like taking a shortcut to your favourite fast-food place.”
Are there White Holes?
“Wow, dad, that was quite insightful. Can you please tell me more about the principle of how wormholes function?” asked Monica.
The Einstein Rosen bridge theory was further expanded where massive blackholes play a vital role in linking two areas of space. Richard explained, “as we have seen from Einstein’s theory of relativity about black holes, matter and light that gets sucked into the black hole is spat out through a white hole in another region of space or even another dimension, perhaps even a multiverse.”
Monica said, “sounds so cool, dad. Does that mean that white holes exist?”
“No honey, the existence of white holes and wormholes are only on paper; they haven’t been proven. No telescope has spotted a region in space where matter and light are being emitted. Also, there is no proof that black holes are portals to other regions in space or another universe; it is all just speculation.”
The Scope of Wormholes
“Oh, I see,” said Monica with a disappointed expression on her face. “So, let’s assume that wormholes are real; if so, what are they useful for?”
Richard replied, “sweetheart, if wormholes are real, they can be used for a wide variety of interstellar travel and travel between galaxies in a zap.” They would be like shortcuts to destinations that would normally take hundreds of years to reach, that is assuming that we could travel at the speed of light. Even though an object would travel slower than light inside the wormhole, it would reach a destination before light itself, as the region inside a wormhole is like taking a very easy shortcut to a location.
“Oh my god, that is so amazing, dad! Hey, tell me what expert scientists have to say about wormholes? Monica said with her eyes filled with excitement.”
“Did you know that several scientists have theorized some concepts that could suggest that wormholes could exist? Yeah, Stephen Hawking says that wormholes could be all around us, but they would appear microscopically small. Within every piece of matter, including time itself, there could be very small holes and wrinkles that are smaller than an atom. Due to them being so tiny, there is no possible way to travel between or manipulate them.”
Magnetic Wormholes
Monica said, “This is really fascinating, dad. Are there other types of wormholes?”
Richard said, “the Einstein Rosen bridge is the theory of a gravitational wormhole, whereas another type of wormhole is known as a magnetic wormhole. A magnetic field can be transferred from one place to another through a magnetically non-detectable path in a magnetic wormhole. Hey, did you know that physicists in Spain were able to create a magnetic wormhole in 2015? They created a tunnel that enabled a magnetic field to disappear at one point in space and reappear at another. Using metasurfaces and metamaterials, they constructed a tunnel that was able to achieve this near unimaginable feat.”
“Thanks for this amazing insight dad, you have made the theory of wormholes play like a documentary movie in front of my eyes. I would love to submit an article explaining this concept for my science project.”
“That’s my girl, remember Monica, the field of science is always ever-evolving, who knows, in the future, we could probably stumble into some mind-blowing evidence that could prove things which are far beyond our current knowledge. Always explore, don’t limit the potential of your brain to mere bookish knowledge, and expand your thinking beyond the horizons of humankind.”
Gravity has been one of the most pivotal forces that bind planets, stars, and galaxies. Scientists have been keen on understanding the nature of elements through mathematical calculations and analytical methods. Theoretical physicists were unable to make head or tail for several unanswered questions that have baffled them for decades. That’s when Werner Karl Heisenberg, a German theoretical physicist, did extensive research and arrived at string theory. Understanding this theory and deciphering it was like finding a needle in a haystack. The string theory was a single mathematical picture that described all forces and matter. It aimed at addressing various theoretical conundrums with the principle of how gravity works as its fundamental point.
General relativity proposed by Einstein states that gravity was a reaction of large objects, such as planets, towards the curved regions of space. However, theoretical physicists were not convinced as they thought that gravity had to behave like magnetism. This is because even small particles such as fridge magnets stick as they swap photons with the particles on the fridge’s surface. Physicists understood that gravity lacked this description from the perspective of small particles among the four forces in nature. They could predict the appearance of a gravity particle but were unable to calculate what happens when two gravitons smashed together, as mathematical calculations showed infinite energy was packed into a small space. This meant that the math lacked something; this was when string theory found its place.
The string theory draws a new perspective of the standard description of the universe by replacing all matter and force particles with just a single element. These tiny vibrating strings twist and turn in a complex manner. Although this theory broadens the perspective of our universe, it fails to unify certain aspects in physics as scientists continue to debate on its relevance and scope for improvement today.
What is String Theory?
Strings can collide and rebound cleanly without implying physically impossible infinities. Quantum mechanics and probability principles were enough to explain the composition of our universe. However, many problems bothered scientists and prevented them from having a good night’s sleep. Quantum gravity was one of the prominent problems in modern physics; it had to reconcile general relativity with principles of quantum mechanics. There were large gaps in developing a consistent theory of quantum gravity due to several problems in black holes, atomic nuclei, and the early development of the universe during that time. One possible solution, which theorists borrowed from nuclear physicists in the 1970s, is to eliminate the problematic, point-like graviton particles.
String theory is a concrete framework that addresses these pressing questions and others. Point-like particles of particle physics could be modelled as one-dimensional objects known as strings. The behaviour of these strings and the nature of their interaction through space is string theory. There is only one type of string that resembles a small loop or segment of an ordinary string. Picture tying a small string between two poles and striking it. Observe its vibration; through this, you can notice that the string doesn’t vibrate in a particular manner. This is exactly how the string particles interact in the universe.
All elementary particles are viewed as vibrating strings. Over large distances, the mass, charge and other properties of the string determine the vibrational state of the string. One of the vibrational states of the string gives rise to a quantum mechanical particle graviton; it carries the gravitational force. Therefore, string theory nothing but the theory of quantum gravity.
How Does Modern String Theory Connect Mathematical Dots?
As science advanced and new discoveries came to light, the String theory was also the subject of modification. The modern string theory was reformulated in 1988 by John Schwarz, an American theoretical physicist, and Andre Neveu, a French physicist. The new string theory was in a league of its own as it did not have to remain consistent with special relativity and quantum theory. This modified theory was the superstring theory that stated that the world comprises three spatial dimensions and one temporal dimension. For the universe to remain finite, time had to be curved as this would require a second temporal dimension. String theorists envision that some multi-dimensional compactification of space existed at every point in space.
Duality, an abstract mathematical relationship between two situations, looks different but could be translated. Theoretical physicists used analogous dualities that bridge unrelated branches in math, such as geometry and number theory. Each operates differently, but dualities enable mathematicians to translate from one another. String theory has the potential to illuminate the dark web by linking different areas of math; this is still up for debate among scientists. Leading scientists believe that string theory still continues to evolve and remains a very productive field of research with the potential to solve long-standing mathematical equations.
Conclusion
Several scientists still debate the string theory’s future, as it has failed to live up to its promise of uniting gravity and quantum mechanics. However, it has become one of the most useful sets of tools in science. If we understand the nature of dark matter and dark energy, it could give us a better perspective of the universe and maybe make string theory more relevant. This is because understanding the dark matter will open up a pandora’s box that would help scientists analyze different aspects regarding dimensions and vibrating strings. The string theory is just a theory and could also be disproved in the future due to new discoveries in cosmology, astrophysics, quantum mechanics, astronomy, or even overall science.
Passion is the driving force of successful physicists and engineers in this world. It pushes people to explore their inner potential and achieve unimaginable heights in their respective fields through revolutionary breakthroughs. Richard Phillips Feynman was one of the greatest minds the world has ever seen. He was an American theoretical physicist who revolutionized physics through his contributions to quantum electrodynamics, integral formulation of quantum mechanics, and particle physics. His contributions in the field of astrophysics are like the building blocks of scientists to emulate. Come, let us dive into the life of this genius to understand his journey and valuable contributions to this world.
A Natural Born Genius
Richard Feynman was born on 11th May 1918 in New York City, USA, to a humble family that migrated from Minsk in Belarus. He was a late talker as he did not speak until his third birthday but later developed a thick New York accent. He was quite close to his younger sister Joan, who shared the curiosity of the world, just like him. He encouraged Joan to pursue her interests in physics, and this led to her choosing a career in astrophysics. Richard’s father was a salesman brought up in a Jewish family. However, despite his religious upbringing, he always encouraged Richard to ask questions to challenge orthodox thinking and religious beliefs. Richard got his sense of humour from his mother, a fun-loving and caring homemaker known for her prominent funny bone.
Ever since he was a child, Richard had a strong liking towards the way things work and was always in the pursuit of knowledge. As a pre-teen, he maintained an experimental laboratory at home and spent a lot of time repairing radios. In high school, he excelled beyond bounds in physics and would always analyze issues theoretically and arrive at the solution. In high school, he was promoted to a higher math class thanks to his proficiency in solving math equations being way higher than his peers. He was such a gem of a genius that he taught himself trigonometry, advanced algebra, integral calculus, and analytical geometry. He also won the New York University math championship during his last year in high school.
An Impressive Student
Feynman joined the Pi Lambda Phi fraternity when he attended the Massachusetts Institute of Technology. Although he majored in math, he switched to electrical engineering and later on changed to physics, which he thought was more accurate for him. He published forces in molecules in his graduate years, which is now known as the Hellman-Feynman therom. In 1942, he received a PhD from Princeton with his thesis being the principle of least action in quantum mechanics.
Feynman analyzed problems in quantum mechanics and applied the principle of stationary action, which paved a platform for the path integral formulation and Feynman diagrams. His supervisor was astonished by his thesis and exclaimed that no physicist on earth could match Feynman’s command over native materials of theoretical science. Feynman had stellar intellect as he was able to decipher the substance behind equations like a walk in the park. He exhibited an enormous amount of dedication and intelligence, just like how Einstein was at his age.
Assisted in Creating the Atom Bomb
In 1941, he got married to his first wife Arline Greenbaum, who passed away due to tuberculosis in 1945. With world war two raging on and the rising tensions between Japan and the United States after the pearl harbour attack, Feynman was recruited by the government to produce enriched uranium for the atomic bomb in the Manhattan Project. He played a major role in this project and developed a formula with leading scientists to create the fission bomb. After a lot of experiments and trials using a miniature nuclear reactor, his team was able to build the weapon of mass destruction. He was able to provide value addition to the team thanks to his prior experience in working with ballistics problems at Frankford Arsenal in Pennsylvania.
Quantom electrodynamics is the study of how light interacts with matter and how charged particles interact with each other. Feynman was known for his contributions in this field. At Cornell University, Feynman worked on a formulation on electrodynamics which was approved by Freeman Dyson, renowned astrophysics at his prime. He proposed a paper on the theory of positrons, which addressed various equations. He also published papers on the mathematical formulation of applications in quantum electrodynamics in 1951, which paved the way for students at the university to aid in the research.
Contributions to Physics and Engineering
At high school, we all would have studied the superfluity of supercooled liquid helium. If you are lucky enough, your school would have also had experiments on exhibiting this quality of helium, where it showcases a lack of viscosity while flowing. Well, guess what? This concept was discovered by Feynman during his investigation at the California Institute of Technology. He proved this through the quantum mechanical explanation of a Russian physicist’s theory of superfluidity.
Feynman was not just the jack of all trades; he was also the master of all. He proved this through his work on the forces like the strong, weak, electromagnetic, and gravity; he established the investigations of all four interactions. This resulted in his success in quantum electrodynamics and quantum gravity. He was a force to be reckoned with in the field of physics as he established a new idea that aided computer engineers. He knew that there was a relationship between physics and computation; he was one of the first scientists to discover the possibility of quantum computers.
Feynman was a person who loved to explore and never had anything called a comfort zone. He was always on the lookout to learn new things, experiment on different aspects, and learn through questioning and reasoning. In 1980, he began working at Thinking Machines Corporation and helped in building parallel supercomputers. He also considered the idea of constructing quantum computers. He proposed the variational perturbation theory that helped in measuring satellite experiments.
A Dedicated Teacher
Feynman was known for his revolutionary teaching methods, which were unorthodox in nature. He often said that students should be made to think in the most open-minded manner like scientists, and teachers have to constantly kindle their creativity and address their doubts with patience. In his lectures, he would give a holistic view of science in the simplest manner that is easily understandable by even a child. He would emphasize the evolution of life and the nature of knowledge transfer of science to the next generation, which is essential as it would enable humans to achieve things in the realm of science fiction.
Feynman often taught concepts in a very engaging manner. Scientists and students who attended his lectures would say that when he teaches a concept, he explains it in a very personal manner that it feels like he is sharing his life experience. He encouraged students and young scientists to constantly question how everything works and, most importantly, what makes everything work. His lecturers were so engaging that people were glued to their seats like toddlers listening to a wonderful tale of the universe and the romantic interaction between subatomic particles.
Nobel Prize-Winning Physicist
Feynman’s achievements in his lifetime are the equivalent of 10 highly intelligent scientists. His dedication and passion for science was immeasurable, and his contributions in astrophysics and particle physics were unachievable by even renowned scientists. He received the Albert Einstein Award and a gold medal for his contribution to physics in 1954. In 1962, he received the Ernest Orlando Lawrence Award, followed by the Nobel Prize in Physics in 1965. He shared the Nobel prize with two other scientists Schwinger, and Tomonaga, for their contributions in quantum electrodynamics and deep ploughing consequences of elementary particle research. He was also elected as a member of the national academy of sciences but resigned after a few years.
In 1978, tragedy struck Feynman when he faced abdominal pain, which was diagnosed with a rare form of cancer. After multiple surgeries to remove the tumour that was the size of a football, his kidney failed due to duodenal ulcer in 1988. He refused to undergo haemodialysis, which could have prolonged his life for a few months. He passed away on 15th February 1988 at 69. His last words being “I hate to die twice. It’s so boring.”
Conclusion
Richard Feynman was truly one of the most remarkable physicists that the world could ever ask for. A Nobel Prize-winning astrophysics who found his work in the minds of several scientists today, he was one of the most magnificent personalities in science. His sense of humour and elegant personality helped him to hit the jackpot with the ladies. He may have passed away, but his work and ideas continue to tingle the minds of young scientists, students, and science lovers. He has proved that passion and curiosity are what drives people to achieve great heights.
Space Age 