Adventures through the laws of Nature
"Physicists spend a large part of their lives in a state of confusion.
It's an occupational hazard."
Brian Greene
American theoretical physicist and science populariser
In our everyday life, we encounter objects of similar size and weight: trees, cars, other fellow humans, buildings... Of course, an elephant and a mountain are bigger and heavier than us, but still they are relatively comparable. There are objects way more bigger: an island, the Earth, stars. The same goes for smaller objects, from a fly down to a molecule of water. This illustrates what scientists call different scales.
At normal scales, we are used to physical laws of a certain type. But does Nature behaves the same in all situations?
It turns out it doesn't. At the extreme scales, the laws are so different that trying to apply an everyday life intuition becomes an obstacle to understanding the Nature. Yet, the Nature follows these strange laws. Our `normal' explanations are just an approximated and incomplete description of what really happens.
We plan to speak about these natural laws. For that we embark on a journey from the infinitesimal small up to the immensely large.
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bizarre world at atomic scales
When things are very small, the concepts of shape and speed get blurred. Objects like atoms and molecules don't bounce off like bowling balls, but rather behave as ghosts in movies, with the ability to pass through each other. How can we describe such overlapped state? If this sounds challenging, then quantum mechanics has the answer!
Lecture 2. Statistical physics:
information, chaos, and arrow of time
When there are too many things, we'd better give up any attempt of detailed description and resort to the idea of getting the most probable outcome. That's the world of statistical physics.
How can we possibly loose track of individual objects? Answering this leads to the concepts of order and chaos, which measure the content of information. Statistical systems are everywhere around us: in a grain of sand, there are more than 1 000 000 000 000 000 000 000 atoms! Also the whole humanity with its 7 billion humans is another example of statistical system.
Lecture 3. Special relativity:
how our perception changes when we approach the speed of light
When you move fast, you see the world differently: time slows down like "molasses" and objects appear closer. Not that you notice the difference yourself: your heart still beats normally and don't feel any pain. What changes is how you (fast) and another person (still) see the world. That's when you both have to call in special relativity. Relativistic effects bring up many uncanny effects, yet the key to measure time with astonishing precision and guide you through the traffic using the GPS integrated into your phone.
Lecture 4. Quantum field theory:
Higgs boson and why did people build Large Hadron Collider
What if throw in small and fast objects? Welcome to the world of elementary particles! The rule of the game is the so-called Standard Model. It basically explains - with no exaggeration - all the invisible up to the visible everyday world with a resounding precision (about 0.000 000 1%).
We have two teams. One is fermions: neutrinos, electrons and quarks. They build up the matter and are not keen to sit exactly at the same spot. The other is bosons: photons, gluons, W- and Z-bosons. They "kick" fermions, exerting forces between them, can pile up in the same place and travel collectively. The most famous boson is likely the Higgs boson. Scientists have suspected its existence for decades in order to explain easily why objects have weight (or better, mass) and it was a big win when it was finally seen for the first time in the Large Hadron Collider near Geneva.
If objects are truly massive, like planets and stars, they can exert huge gravity on astronomical bodies. That's the same force that makes us feel weight on Earth. Rather than forces though, modern scientists understand gravity as the geometry of space (and time). That is the realm of general relativity. Massive objects curve the fabric of space, like pushing an elastic band, and get deflected back by space itself, in a two-way intertwined fashion. What looks the curved orbit of Earth around the Sun is nothing but a straight line on the curved fabric of space. This is also the right time to discuss solar systems around far-away stars, the evolution of stars and history of the Universe.
Lecture 6. Theory of everything:
what scientists are dreaming about
At last, what if one thing is massive, small, and fast? This is the smallest scale conceivable of the so-called Planck scale, at which the matter and space-time are expected to get blurred into one only concept. That's the realm of what scientists often call the theory of everything. However, what is this scientific model and how bizarre it could be, nobody really knows yet.
Over the last 50 years, scientists have come up with many intriguing ideas. We are still have a long way to go, as the Planck scale is fifteen orders of magnitude away from modern experiments, roughly the same number of orders that ancient Greeks were away from modern science. We can only wonder how many new exciting discoveries await us falling down such world!