The Symmetry of Space and Time

You are in 9th grade, your mind completely relaxed and oblivious to the harrowing journey it is about to be taken on. Your first physics class starts, and the teacher spews some jargon. Two words catch your attention: ‘position’ and ‘time’. It turns out that for the next two years of physics, these two words become extremely common. Most physics turns out to be described in terms of position and time, and these become the two variables you find most commonly in your numerical calculations.

You are now in 11th grade. Position and time take on a whole different meaning. Position is now an abstract mathematical quantity referred to as a vector, and it is usually expressed as a function of time. For the rest of your high school career as a student interested in physics, things you had learned before take on a more rigorous form, integrating a deep mathematical structure with a physical understanding of the world. Earlier, you only thought of space as the place outside the atmosphere. Now you realise space is where your position vectors live and evolve as time goes on independently. You learn that physics is written in the language of differential equations, and you learn how to solve these equations. All of this is extremely exciting, and you can’t wait to learn more when you go off to university. If only you knew…


What you just read is not my life story. This is how millions of students have been introduced to physics, and it’s not a bad place to start. But our understanding of physics has evolved so far beyond just some vectors and functions.
The first great leap in our understanding of physics happened over a century ago, in 1905, also known to some people as Einstein’s annus mirabilis – his year of miracles. That year, he published four papers that changed the entire face of physics, but for this discussion, I am interested in only one – “On the Electrodynamics of Moving Bodies.”


(The original paper was in German, but let’s stick to English. Mein Deutsch ist nicht so gut.) This paper addressed the discrepancies in Maxwell’s calculations of the speed of light, which seemed to be frame independent and questioned our understanding of Galilean relativity and came to a revolutionary conclusion. Speed of light is invariant with the change of frame of reference. Time is not. This changed how we viewed our universe as a three-dimensional vector space parameterised by time as an independent variable; time also changed with speed, same as position! This gave rise to the almighty “Covariant Derivative”, which treated space and time on equal footing with only minor differences in constants. Our space was no longer Euclidean space; it was Minkowskian. Vector calculus was no longer enough to study physics; tensor calculus was needed.


Ten years after Einstein shook the very foundation of our understanding, he came back again with General Relativity which further solidified the views of unified space-time. Bodies of high mass and energy warping the space and time coordinates in their vicinity and mathematics so complicated that it took nearly ten years to formulate.


All this progress presented a problem. Since contemporary ways of calculating conserved quantities were no longer valid, could we consider them as conserved anymore? Enter the saviour, Emmy Noether, who proved that conserved quantities were a product of the symmetries of nature, such as momentum was conserved because of continuous space symmetry, and energy was conserved because of conserved time symmetry. As if we needed more proof of the underlying deeper meanings to space-time….


Today, these subjects are widely studied and even more widely known among physicists and other scientists alike. In fact, when the next big thing came along, aka Quantum Mechanics, physicists were not happy till they found a covariant way of doing quantum mechanics which held space and time of equivalent footing and was invariant under Lorentz transformations. Even modern theories such as String theory and Quantum Loop Gravity are often held to the test of covariance. Tensor calculus (the way Einstein re-invented it) has become the norm of writing physics expressions.

You might be thinking, what if what we’re studying right now isn’t deep enough? Maybe there is a more elegant formulation of physics? You wouldn’t be wrong since there is already some research going on in probing the base postulates of quantum mechanics and the nature of our reality. But it might be a while before we get the next big idea in physics. After all, it took nearly 250 years since Newton to get Special Relativity.

– Shobuj Paul

Header image from here.

Humanity’s Fascination with Mars

Mars, the Red Planet. Our cosmic planetary neighbour. In February 2021, UAE joined an elite group of countries who have successfully reached Mars, India having achieved this feat in 2014. Sending a probe to Mars is one of the brightest feathers in the cap of any space agency.

No other planet has captured the imagination of humanity like Mars has, and none probably will, at least for a very long time. When one looks at it objectively, it can actually be hard to imagine why that is the case. Neither is it the closest planet to Earth (Venus gets closest to Earth, and on an average it is Mercury that is closest to Earth), nor is it extremely interesting to look at, nor does it have conditions suitable for life. For starters, its average temperature is -60 degrees celsius. Its atmosphere is so thin that a human’s blood would boil if they stand on the Martian surface without a protective suit. It does not contain any appreciable amount of water, except what is frozen at its poles.

Why then, has humanity attempted to send missions to Mars a whopping 49 times?

See reference below

An analysis shows that Mars is by far the most explored planet of the Solar System, well apart from our own planet Earth of course. Considering how expensive interplanetary missions are, why are we pumping this amount into Mars exploration?

The reasons are several, but one of the very first would have to be the long-debunked idea that Mars is home to aliens. In the 1800s, observatories with larger and larger telescopes were built around the world. In 1877, Giovanni Virginio Schiaparelli (1835-1910), director of the Brera Observatory in Milan, began mapping and naming areas on Mars. He named the Martian “seas” and “continents” (dark and light areas) with names from historic and mythological sources. He saw channels on Mars and called them “canali.” Canali means channels, but it was mistranslated into “canals” implying intelligent life on Mars. Because of the then recent completion of the Suez Canal in 1869 (the engineering wonder of the era), the misinterpretation was taken to mean that large-scale artificial structures had been discovered on Mars. This myth was later debunked, and it was realized that these observations were due to human tendency of finding patterns where none exist.

The notion of bright red Martians landing on and invading Earth is the content of several sci-fi flicks of the 20th century, the beginning of which was HG Wells’ ‘War of the Worlds’ in 1898. In 1938, a radio broadcast of the novel was presented as a series of news bulletins, which led to panic as people mistook them for actual news of a Martian attack.

In 1965, Mariner 4 performed a flyby of Mars, leading humanity to witness close-up images of the red planet for the very first time. However, the data of the probe made it clear that Mars was inhospitable; it has very low atmospheric pressure and temperature.

Somehow though, it is this early interest in Mars that led to more missions being sent to the planet, and led us to study its atmosphere and surface features in great detail. Modern interest in the planet stems from the fact that Mars could have been hospitable to live millions of years ago, and it is a mystery how Mars lost most of its atmosphere and water. There is evidence of river canyons, channels and gullies all over the surface, indicating possible liquid water flow. Subsequent missions have found water under the Martian surface, as well as several sedimentary rock formations which strongly indicate that the surface of the now-barren planet was once covered with water. 

The final and the most recent reason for humanity’s deep interest in Mars is the exciting possibility of the red planet being humanity’s second home. Colonization of Mars is being seriously considered. Mars has enough gravity to be adaptable for human bodies. Reasons for colonizing Mars include pure curiosity, the potential for humans to conduct more in-depth observational research than unmanned rovers, economic interest in its resources, and the possibility that the settlement on other planets could decrease the likelihood of human extinction. Perhaps, sending a human to Mars will be the next big achievement of our species, and one that might even happen in our lifetimes. Until then, we wave hello to Mars right here from Earth!

References:

https://www.scientificamerican.com/article/which-planets-do-space-scientists-love-most-mdash-and-least1/

Udbhav Sinha

The God Particle

Log Entry 3… 100?

It really takes a toll on you, spending hours and days floating around in space. The mind wanders and reminisces, thinking back to all the mundane days. I remember, it was a very cold day and I could barely get out of my bed that morning. With a lot of effort, I finally pulled myself out of the bed. I felt so weighed down and suddenly thought, how did so much of mass come into existence. I was weaving the story in my head and I saw the book kept on the desk, The God Particle: If the Universe Is the Answer, What Is the Question? I quickly turned the pages and suddenly my attention went on the word Higgs boson. Higgs boson, also called Higgs particle, particle that is the carrier particle, or boson, of the Higgs field, a field that permeates space and endows all elementary subatomic particles with mass through its interactions with them.

Higgs, it intrigued my attention. I quickly sat and started scrolling about its existence. I found that in an event recorded in 2012 by the Compact Muon Solenoid detector at the Large Hadron Collider in proton-proton collisions at a centre of mass energy of 8 teraelectron volts. In this event there was a pair of Z bosons, one of which decayed into a pair of electrons while the other Z boson decayed into a pair of muons. The combined mass of the two electrons and the two muons was close to 126 GeV. This implies that a particle of mass 126 GeV was being produced and subsequently decaying to two Z bosons, exactly as expected if the observed particle were the Higgs boson. I was bamboozled it was a breath-taking discovery. I was very curious to know more about it.

Physicists Observe Higgs Boson, the Elusive 'God Particle' | US News

Over the decades, particle physicists had developed an elegant theoretical model that gave a framework for the understanding of the fundamental particles and forces of nature. One major ingredient in this model is a hypothetical, ubiquitous quantum field that is supposed to be responsible for giving particles their masses. This field would answer the basic question of why particles have the masses. This field is called the Higgs field. As a consequence of wave-particle duality, all quantum fields have a fundamental particle associated with them. The particle associated with the Higgs field is called the Higgs boson. Because the Higgs field would be responsible for mass, the very fact that the fundamental particles do have mass is regarded by many physicists as an indication of the existence of the Higgs field. We can even take all our data on particle physics data and interpret them in terms of the mass of a hypothetical Higgs boson. In other words, if we assume that the Higgs boson exists, we can infer its mass based on the effect it would have on the properties of other particles and fields.

This was one of the most iconic Nobel discovery of 21st century. I hadn’t realised that my coffee is no longer hot but my mind surely was with the extremely unique particle. Coffee, I miss coffee. The designers of my vessel didn’t think to add something like an ISSpresso. Sigh, I wonder what got me thinking of home and the God Particle, maybe it’s me hoping for a miracle.

Received by Harshit

AI in Space Tech

With the advent of commercial space exploration companies like SpaceX and Blue Origin and increasing expenditure of governments worldwide into space technology, it is only a matter of time before mankind becomes an extra-terrestrial species. In fact, many believe this to be the only logical next step for man, considering how our home planet has finite resources and an infinitely growing population. While this will require immense effort in the fields of rocket engineering, another slightly unexpected aspect of this space race interests me. The increasing use and future potential of Artificially Intelligent systems in space.

Machine learning has two broad applications in space:

  1. Analysis and Prediction:

            While “Big Data” has only recently become a buzzword in the tech circles due to the rapid and widespread use of the internet, this is not the case for space exploration. Be it a large radio telescope array gathering information about a distant galaxy, or a satellite orbiting Jupiter and transmitting these readings 24/7 to an operator on earth, Space exploration has always involved massive amounts of data. As an example, NASA collects approximately 2GB of data every 15 seconds from all its satellites. However, only a fraction of this data is analysed due to limitations in time, manpower and resources. Thanks to AI, this can be done much quicker, and to a decent level of accuracy. NASA annually conducts Frontier Development Lab (FDL) sessions for 8 weeks every summer where technology and space innovators are brought together to brainstorm and come up with code to solve a variety of problems. FDL also partners with big tech companies who provide the scientists with an advanced tech repository of sorts in the form of hardware, algorithms, super-computer resources, funding, facilities and subject-matter experts. Recently a team of scientists came up with a model to analyse the massive data generated by the Kepler mission to search for habitable exoplanets by analysing the emission spectrum of these systems. Since there have been thousands of exoplanets discovered so far, making quick decisions about which of them are the most likely to harbour life can help us narrow down candidates for further detailed (and costly!) exploration. Another interesting outcome of FDL was an algorithm that used radar data from nearby asteroids to model the important parameters like their shapes, sizes, and spin rates which are critical in NASA’s efforts to detect and deflect threatening asteroids from Earth. While traditional methods could take up to 3 months to model a single asteroid, this ML model can complete the task in just 4 days! Another great example of the use of ML was the development of a “virtual sensor” which could fill in missing data gathered from sensors aboard the Solar Dynamics Observatory (SDO) by analysing historical trends.

In the future, the predictive power of AI could be extensively used for tasks ranging from charting out interstellar travel courses to helping us analyse distant star systems with high accuracy

2. Real-Time Decision Making:

So far, we have seen how ML can be used to predict or analyse large volumes of data. This field of AI is often termed as “supervised learning”. However, there’s another area of ML termed as “reinforcement learning” that has great potential as well. Essentially, reinforcement learning aims to mimic biological learning by making a robot repeatedly try a certain task. If the robot succeeds, we reward it with a “cookie” else if it fails we “punish” it. Thus with time, the system learns how to execute a particular task.

 Presently there’s a whole host of dangerous operations like spacecraft repairs that astronauts may have to perform in worst-case scenarios. Reinforcement learning algorithms show great promise in these areas. By simulating scenarios artificially in labs, we can “teach” robots to carry out various critical tasks that are otherwise too risky for humans. Apart from this, a combination of RL and supervised ML could also be used to develop systems that help humans carry out mundane or time-consuming tasks which could arise especially in long term space travel. In 2018, the German Aerospace Center (DLR) launched an AI assistant to support its astronauts in their daily tasks onboard the International Space Station. CIMON (Crew Interactive MObile companioN) is fully voice-controlled and can see, speak, hear, understand and even fly! CIMON returned after 14 months, but CIMON-2 arrived in December 2019 to replace it. The Japanese Space Agency (JAXA) has also taken pioneering steps in this field by developing an intelligent system that is currently aboard the International Space Station taking pictures of experiments in the Japanese module, KIBO. JAXA’s Int-Ball operates autonomously and can take pictures and videos. It was developed to promote the autonomy of extra- and intra-vehicular experiments while seeking to acquire the robotics technology necessary for future exploration missions. Scientists believe such robotic systems could also help in interstellar travel to navigate potentially deadly spaces like asteroid belts.

That being said, we still have a long way to go before AI systems like TARS from interstellar are developed. The key issues that are faced by the industry today include:

  1. Expensive nature of space engineering: Before any RL/ML system is deployed there comes the monetary expenditure that could potentially be wasted if the mechanical systems onboard fail to operate as expected.

  2. Unreliable results: Since ultimately any AI is only as good as the data we feed it, there’s a decent chance that the predictions made are inconsistent with our expectations, especially if the input data is noisy. Thus more research needs to be done to develop robust systems capable of generating reliable output to make their use more widespread.

  3. Separation of academia: Traditionally, space has been the domain of engineers and physicists while the fields of AI have been home to computer geeks. Since the two fields are so widely separated, it is very unlikely that intra-disciplinary discoveries are made. With initiatives like FDL, this gap is being bridged steadily.

With cutting edge technology being developed this very instant by some of the largest tech companies on the planet like Google, SpaceX and NASA, I strongly believe that the time when mankind will have settlements on other planets will occur within our lifetimes and no doubt AI would have played a pivotal role in this expansion.

Till then, May the force be with us all!

— Shreyas Bhat

First Man: Damien Chazelle

This fantastic movie is sure to give goosebumps to everyone, especially to those fascinated by space and aspiring astronauts. It depicts the journey of NASA towards the exploration of our very own natural satellite in a tough race with the Soviets. When President Kennedy said, ‘Let’s go to the moon,’ it was simply impossible in the 60s. In eight years, NASA and the 400,000 people working for NASA literally invented the rocket, the spaceship that could land on the moon, the space suits, everything invented from scratch. The mission cost about $20 billion.

Cosmic pioneers, Neil Armstrong, Buzz Aldrin and Michael Collins are all set for their flight aboard the Apollo 11 mission, little knowing that they were on their way to creating history.

FIRST MAN (2018) • Frame Rated

With the death of their daughter, Karen, an emotional roller coaster begins in the lives of Neil and his wife, Janet. To forget the pain and keep himself occupied, he enrolls himself for NASA’s Apollo mission as a trainee astronaut. His wife, Janet, moves to Houston with her husband and their two young sons, Mark and Rick after Neil is accepted into the Gemini program. She is a strong woman and even forces Neil to explain the perils of his mission to his sons, Mark and Rick to mentally prepare them for the worst as she seems to move through her days in anticipation of widowhood.

The first-manned Apollo mission went through a series of trials and errors. Dangers were faced, including the deaths of astronauts Ed White, Gus Grissom and Roger B. Chaffee during the pre-flight testing. Their deaths register mainly as threats to Neil’s safety and the future happiness of his family. Later, NASA redesigned the hatch and enacted other safety measures, which ensured that the Apollo 11 mission wouldn’t face similar obstacles in space.

Neil is constantly disturbed due to his daughter’s death, his colleagues’ deaths, his under-stress marriage, his daring job and the uncertainty of the mission. After rigorous training and a lot of anticipation, comes the most challenging day, July 21, 1969. Neil and his Crewmates are fitted into their astronaut suits and experience bone-rattling vibrations during take-off. They study the instrument panels in front of them along with processing instructions by mission control, knowing that a wrong move could mean their end.

Three days post-launch, Apollo 11 enters the lunar orbit. Armstrong and Aldrin undock in the Lunar Module Eagle and begin to land. After the landing site terrain turns out to be much rougher than expected, forcing Armstrong to take manual control of the spacecraft, he lands Eagle successfully at Tranquility Base. In the meantime, the craft was running low on fuel, meaning there was a possibility the astronauts would have to abort the mission, but it was a manageable event. Therefore, making his much-awaited step on moon and uttering his famous line, “That’s one small step for man, one giant leap for mankind.”

Then, as a memory that would live forever, he drops his most priced possession, his daughter’s bracelet into one of the craters. After their journey back to earth, they are kept in quarantine in a fear of contracting any kind of space virus.

The fact that he accepted the mission showed his immense trust in NASA even after a few accidents and his feat concludes that dreams do come true.

Dhriti

Neutron Star Collision

Log Entry 2

I woke up from my hibernation (yes, things got a bit boring) and could hear the controls beeping owing to the ripple in space-time, the gravitational-wave detectors picked up some signals. I expected it to be a pair of huge blackholes quickly spiralling into each other, but no, I was wrong. The new siren lasted longer, for about 100 seconds with frequencies rising up to thousands of cycles per second (it lasts only for a few secs and frequencies up to tens of cycles for blackhole merging)

What I saw was a bright spot of light, that faded from bright blue to dim red and eventually disappeared, it was emitting X-rays and radio waves after initial couple of weeks. There was gravitational waves and electromagnetic radiation both coming out of a single source. I was startled at the sight, not able to make sense of what I was witnessing. Little did I know I’d seen a rare event that occurs about once in 50,000 years… yes you read that right, ONCE IN 50,000 YEARS. It was a collision of two Neutron Stars.

Collision Of 2 Neutron Stars – Seen For First Time – Spews Massive Cloud Of  Gold, Heavy Elements : The Two-Way : NPR

What I witnessed as light from it, was the “kilonova” – produced as a debris from the merger, expanded and cooled.

Neutron stars collision is a rare phenomenon, where two neutron stars close enough to each other, spiral around each other rapidly and eventually merge into a singularity forming a blackhole. It is the origin of gamma ray bursts (second most powerful event known) shorter than two seconds.

As the two neutron stars twirl together and rip each other apart, they expel neutron-rich atomic nuclei, forming a shroud of matter totalling a few percent of a solar mass. Those nuclei gobble neutrons in rapid succession and then quickly change their chemical identities through radioactive decay. This is the so-called r-process—or rapid neutron capture process—that makes the shroud glow for a few days, and its light reddened by heavy elements that soak up blue wavelengths. This is what is called the kilonova.

Thanks to the colliding neutron stars we have gold, silver and platinum for the origin of half the elements heavier than iron, including silver, gold, and platinum are generated in the r-process.

I remember, a Neutron Star Collision was observed for the first time on 17th August, 2017. The LIGO picked up unlikely waves at 12:41 universal time. Scientists all over the world observed this phenomenon for several weeks, the neutron stars swirled around each other, coming closer and closer. From passing about 30 times each second, the pair reached a point around 100 seconds later when they were swirling 2,000 times each second. After that, there was a short pause when nothing was detected by LIGO. Then, the stars violently collided, most likely creating a black hole; making that, probably, the first time, scientists have witnessed a black hole being made.

After witnessing this mind-boggling phenomenon I’m heading towards a new place, feeling relieved of the fact that the phenomenon occurred far away from our dear Earth, else the burst of gamma rays would have catastrophically stripped half the Earth’s upper atmosphere.

Received by Shilpashree

What Would Animals on Mars Look Like?

Disclaimer: This a work of fiction, a mere figment of my imagination.

Abstract: Life on Mars as we know it doesn’t exist on the “surface”, but there is potential for the Martian subsurface to host a habitat for life. The information that we have gathered about the Red Planet’s subsurface right now, doesn’t tell a whole lot about whether it’s a habitable environment or not but, we have brains, so let’s imagine that the subsurface is hospitable for organisms. If it  is hospitable, what would be the characteristics of the animals living there? What would they look like?

Let me give you a rough idea about them, with some illustrations.

Statement

Now, for the kind of organism I would like to present, talking about a micro-organism would be boring, so let’s say the habitat can be sustainable for a small “animal”. Speaking about how the organism would perform basic metabolic functions, etc. would require a clear understanding of the chemical nature of the Martian subsurface, because there’s a lot of science which my poor brain is incapable of grasping easily, mainly a lot of chemical equations and biochemical processes, let’s just stick to the physiological aspects of this organism as it would be easier for me to present.

Basic Features

The organism is subterranean, i.e. it dwells underground. Hence it is comparable to the subterranean organisms we have here on Earth.  Another comparison we can make is to the Fossorial animals. A Fossorial (from Latin fossor, meaning “digger”) animal is  one that is adapted to digging and lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders. Using these known organisms as references, we could predict what adaptations our Martian subterranean animal would be equipped with. There are six major physical adaptations that may exist in the animal:

  1. Fusiform: Meaning a spindle-shaped body, tapered at both ends, adapted for the dense subsurface.
  2. Poor (or lack of) eyesight: Due to darkness in the subterranean environment, visual organs would be completely useless.
  3. Small (or missing) external ears: In order to reduce friction while burrowing it is efficient to reduce protrusions on the body.
  4. Short and stout limbs: Shorter limbs enable more strength output, which is important for locomotion.
  5. Short and broad forelimbs: Forelimbs are broad as a higher surface makes it easier to excavate. Long claws also help loosen up burrowing material for the hind limbs to disperse back.
  6. Short or no tail: Enables little to no locomotor activity or use to burrowing animals.
  7. Skeletal adjustment: The skeleton would show a triangular skull, chisel shaped teeth, prenasal ossicle (inner ear) and effectively fused or short lumbar vertebrae (segments in the backbone).

The following Illustrations would present a better understanding of the adaptations.

Illustrations

Figure 1: Predicted Skeletal Structure

I present to you this skeletal diagram of how the animal would look like. From the points discussed, we would also be able to predict how the muscle groups would work. This particular “rodent” would boast exceptional neck and forelimb muscles that would enable it to provide high power output necessary for burrowing.

If we take a look at the skull, we can observe that it would be particularly streamlined. Also, take note of the huge mandibles (could be assigned to cartilage and small muscles for precise movements too).

Figure 2: Skull anatomy

The important part here is the auditory chamber (I made this word up). Subterranean animals usually possess sensitive auditory organs which can be modified to be sensory. These organs enable them to understand their surroundings through seismic vibrations and sounds.

Finally, the forelimb:

Figure 3: Forelimb

As the forelimb does most of the “digging” work, the tip of the phalanges is modified to be long. Also, having shorter limbs increases output power.

Final Notes

These predictions are in no way accurate (lol). It’s not possible to make accurate predictions without more information about the ecosystem of the animal. Knowing the ecosystem too wouldn’t be enough, as other factors like mode of nutrition, mode of reproduction, etc. would come into play. But as I said before, this is a mere figment of my imagination which I hope could spark some sort of idea or enjoyment in your head. Cheers.

References

Michalski, Joseph and Onstott, Tullis and Mojzsis, Stephen and Mustard, John and Chan, Queenie H. S. and Niles, Paul and Johnson, Sarah: The Martian subsurface as a potential window into the origin of life Nature Geoscience, December, 2017

Anvith M

The Strangeness of Quantum Mechanics

The 20th century has seen the most significant advances in science and physics, especially the birth of two great theories, General Relativity and Quantum Mechanics. The unification of these two is said to be the “theory of everything”, the holy grail of physics. While GR is a beautiful theory, Quantum theory, as we may have heard is often called “strange”,” un-understandable” or even “nonsensical”. Richard Feynman said, “I can safely say no one understands quantum mechanics”. What is it about quantum mechanics that prompts even physicists make such comments? It is known that Quantum mechanics has been very successful and explains almost all of chemistry as well. Therefore, it is remarkable that the apparent strangeness leads to no inconsistencies. How has physics made sense of this?

But why was quantum theory needed in the first place? Before discussing QM itself, we need to understand the ‘why’ of it.

Why Quantum Theory?

From the beginning of the 20th century, many observations were made which did not obey the then existing laws of physics. Planck’s law of radiation implied that the frequency of oscillators in a body is quantised. The photoelectric explanation by Einstein suggested that light is composed of particles, called photons. But light was already established to be a wave! How could something sometimes behave like a particle and sometimes, a wave? Atomic stability was a mystery. Bohr assumed discrete values of angular momentum of electrons in orbit and the Bohr model proved to be successful. However, the discrete values of angular momentum were against the classical view. The Stern-Gerlach experiment showed the electron has only two spin orientations.

So then, clearly, this impressive array of startling phenomena needed a new theory, probably just as surprising. Thus, came the need for quantum theory.

What is Quantum Theory, and why is it strange?

Quantum theory was gradually developed by several people and attained a final form at the late 1920s. Many ideas were put forth; however, it must be noted that all of QM follows from a small set of assumptions which themselves cannot be derived. Therefore, QM is based on axioms.

Looking at the wave-particle duality of light, in 1924 De-Broglie proposed that particles too could behave like waves. He put forward a relationship between the momentum of a particle and its wavelength, which could explain Bohr’s assumptions in his model of the atom. Thus, quantisation conditions came naturally from De-Broglie’s hypothesis.

The next big addition to QM is the Uncertainty principle/relation. The uncertainty principle is certainly one of the most notable aspects of quantum mechanics. It has often been regarded as the most distinctive feature in which quantum mechanics differs from classical theories. This was put forward by Heisenberg in 1927 using a theoretical ‘light microscope’, which took in Einstein’s formula for the energy of a photon. He showed that it was impossible to measure precisely the position and momentum of any particle. However, it must be noted that this is not due to lack of good measuring instruments but a fundamental restriction of nature itself. This led to a lot of doubt among many physicists, and as Einstein said, ‘God does not play dice with the Universe’. How could you proceed with physics if you could not measure properly in the first place?

Meanwhile, in 1925, Schrödinger expressed de Broglie’s hypothesis concerning the wave behaviour of matter in a mathematical form and arrived at the Schrodinger wave equation (SWE). This was wave mechanics, and it revolved around a quantity called the wave function. The wave function(psi) is the probability amplitude of finding a particle at some place. Thus, the concept of determinacy was reduced to probability. Therefore, the maximum anyone can know is the wave function! The modulus squared of psi was interpreted by Max Born as the probability. Thus, the probability of finding a particle anywhere, which was most that could be done, was governed by the SWE.

Another big change was the concept of measurement in QM. The Uncertainty principle implies that any quantum measurement has uncertainties. This means the outcome of an experiment cannot be predicted with certainty, like the roll of a die. Therefore, this led to a re-interpretation. The new view was that any state, before being measured, would be a superposition (writing a quantity as a sum of individual quantities, here the different states) of all possible states that can be measured. However, it must be noted that superposition doesn’t mean the system is at all of the states at the same time, as some people have interpreted. Representing a state as a superposition of eigenstates of the observable is a mathematical notation. The measurement of the state causes it to collapse into one of the eigenstates of the observable and yields an eigenvalue. This is called the Copenhagen interpretation. This was a radical change as opposed to the classical measurement, which was definite and had no concept of superposition. Thus, something as simple as measurement took an unknown face in QM.

However, physicists also made different interpretations. They said that the wave function did not actually collapse. Instead, it branched off into another reality on its own, where the measurement yielded another eigenstate. This means that all possible outcomes of an experiment are physically realised in some other ‘universe’! This is called the many worlds interpretation of QM.

The great physicist Richard Feynman devised a radical way to look at QM. He extended the concept of the double-slit experiment to infinite slits. He said that a particle going from A to B would take all possible paths (that’s right, all of them!) between A and B, each of which would contribute a number. From this picture, he formulated a mathematical quantity called the Path-Integral, which could again explain all of what traditional QM had done. This is an alternative way to do QM and not an interpretation and its called the Path-Integral formulation of QM.

Thus, the simple picture of classical mechanics now became a probabilistic picture. The outcome of a measurement cannot be predicted with certainty but by the probability of observing a particular state given by the SWE. This could imply the existence of different Universes where a particle takes infinitely many paths to go from A to B! Despite such a strange view and a ‘major setback’ to science in terms of measurement, Quantum Mechanics has been highly successful and can explain a large portion of Chemistry in itself, along with making new advances like Quantum computing. That’s the power of physics and maths (they must co-exist! lol), taking the strangest of observations and making a theory that describes nature. As the Universe surprises us with new concepts, physics follows with an explanation. But, as the quantum world has shown us,

Not only is the Universe stranger than we think, but it is also stranger than we can think.

Werner Heisenberg

Rakshith Rao

Interstellar: Christopher Nolan

Wormholes, space travel, time jumps. This movie provides the kind of rarely met satisfaction to the Sci-Fi enthusiasts (read: nerds) out there. And if that wasn’t enough the visuals in the movie are beyond stunning, starting from the frightening emptiness of space, the artistic beauty of a black hole, or the creativity of the planets with their varying atmospheres and landscapes. All of that without even taking into account the kind story that would have any viewer teetering on the edge of their seats.

Interstellar - Most Famous Movie Quotes to Ponder

All in all, it is a movie worth watching even if you’re not a Sci-Fi fan, only if it is just for experiencing the tear-jerker that it is. The emotional impact of being out in space and losing time due to time dilation seems like concepts which won’t relate to the average viewer but the story-telling manages to still achieve just that, having us wiping at our eyes when Cooper finally reunites with Murph on her deathbed.

The movie keeps itself grounded without taking too many creative freedoms with the physics of it all, which is quite admirable in today’s film industry. The portrayal of the black hole and the effect of its gravity on time is something deeply rooted in the Einstein’s General Theory of Relativity. And the kind of robotics shown in the movie is not something that is too far from today’s reality. We might be far from the kind of advanced space travel showed in the movie, but the intercept maneuver is something that is used by to redirect satellites even today using a planet’s gravity.

Film Review: Interstellar. Let's get this out of the way first… | by Will  Clayton | CineNation | Medium

The dystopian future where humanity is threatened by extinction due to food crisis isn’t one that in too hard to believe, and neither is the wild scramble to preserve our existence. Interstellar tells a compelling story of a team of astronauts looking to find a new home for the human race, but running into problems that seem inconceivable to the human mind like survival on a frozen planet and obtaining data from inside the event horizon of a black hole but make us empathize nonetheless.

Shobuj

Solar Flare: A Cosmic Flamethrower

Log Entry 1

All I remember saying is “Major Andy, reporting for duty”. Now, I find myself in a vessel floating in the vast expanse. I looked out the window to see a distant planet, but a look to the left revealed something much closer, almost blinding. “Thank goodness for the UV blocking windows”, I thought as I beheld the Sun in all its glory. That wasn’t all. A glance at the X-ray imager revealed an explosion of energy radiated out, with no plans of returning. The data also showed freckle-like Sunspots near the origin of the radiation. I deduced that it must be a Solar Flare.  

Solar flares are predicted by new model – Physics World

Solar Flares are typically caused by the tangling or reorganising of the strong magnetic field lines from active regions on the Sun. They send out light in almost every wavelength across the spectrum, as well as accelerated subatomic particles such as electrons and protons. 

I wonder if the first people to observe flares, Richard Christopher Carrington and Richard Hodgson, ever dreamed of being here.

The first observed flare, in 1859, was associated with a major coronal mass ejection (CME), huge outpouring of energy and material. The fastest ejections reach Earth in less than two days, travelling up to 1,000 kilometres (620 miles) per second. When the Sun is at solar maximum, the period in its 11-year cycle when its activity is at its highest, the Sun can unleash over 100 solar flares every week. A flare could be my ticket home, if only it wasn’t almost as hot as the core of the Sun, several million Kelvin! 

I remember reading, scientists classify solar flares based on how brightly they shine in x-rays, which in turn reveals some of their potential effects. The smallest C-class flares (which I probably observed) are barely perceptible on Earth, aside from the blast of light seen by x-ray satellites. Medium M-class flares can cause brief radio blackouts around the poles and minor solar storms. But the largest solar flares, called x-class events, can disrupt global events radio signals and cause stronger, longer-lasting solar storms.

In March 1989, one of the largest CME on record, caused a geomagnetic storm in Earth’s atmosphere that crippled the Hydro-Quebec power grid in Canada; that was an X15 class flare. 

Solar Flares seem like Earth’s worst nightmare, especially for a civilisation that thrives and depends on Electricity. They do have a silver lining, rather, a spectrum of green and pink- Auroras. They are created as charged particles from the sun slam into our atmosphere and cause atoms in the air to glow with vibrant colors. The best, most intense auroras appear when Earth is subjected to an onslaught from a solar flare.

The Northern Lights: Frequently Asked Questions | Hurtigruten

The images of the beautiful Aurora gives me a little peace of mind as I drift across the universe, not knowing where I’m headed. 

Transmission: Message In a Bottle

Received by Varsha and Samshrita