What I Love About PhysicsPositronWildhawk For a long, long time, we have all been putting our minds into the science of everything we know of. The underpinning of all that exists. The glue that keeps the universe intact, and of course, possible. And we continue to unravel more fascination. The Ancient Chinese Astronomers who observed the motion of the stars would never have pictured the clusters of balls of hydrogen plasma like our Sun that we know of now. Newton did work on gravity in relation to force and mass, but would never have pictured quantum foam or quantum loops, which is on the frontier of evaluating gravitational interactions on a quantum level. And waves and particles were described as separate entities for a long time before we found their dual behaviours which we use a lot today. It's how we continue to find new things that were well beyond our previous conceptions that prove to you that Physics is the concrete journal of our progression of accomplishments and our knowledge of all that we know of. So let me prove the wonders.
We have, for instance, the science of the quantum. The basis of everything, yet so complex in its difference with classical physics that sparked one of the greatest rows in science, but also developed some of the most fascinating and mind blowing concepts that we know of, and is still taking us on a tour of some amazing discoveries. The founder of this science is Max Planck, who pictured corpuscular light, which transfer energy in quantised bullets in proportion to their frequency. This ratio being Planck's constant; the value of the actions exerted by each photon in joule seconds, confirming the increased power of a photon in proportion to its frequency. That's why blackbodies begin to emit infrared light, but eventually heat up to emit visible light at what's called the Draper Point (798 K). And so, every light bulb, every fire, every source of heat and light, spells out this phenomenon.
The idea of quantised energy was later proven by Einstein with photoelectricity, in which photons transferred energy to each electron within a metal in turn. Which was clear evidence for light as particles, as Planck had suggested, because the electrons in question could only be emitted above certain frequencies of light. If this were expressed as waves, the energy would be transferred continuously and not in quantised values, therefore said electrons would have been emitted according to light intensity and not frequency of the light.
So light could behave as both waves and particles. And so could matter, as physicists were also able to diffract electrons through a gap like light. But having one with the other can determine certain phenomena in various properties of light and matter. For instance, why does light diffract according to wavelength? It's all down to the Uncertainty Principle; one cannot simultaneously determine a quantum object's position and momentum. Light diffracts because making it traverse a gap reduces uncertainty in position, therefore uncertainty in momentum increases, and with momentum being a vector quantity, scattering the light spreads out the momentum. If one diffracts higher frequency light, the uncertainty in position is reduced further by positions between any two wavefronts. So whereas the momentum is still uncertain, de Broglie's equation determines it has a greater value. With momentum comes inertia, so there is less diffraction of higher frequencies.
The evaluation of matter as waves was taken to new levels with the patterns obeyed by these waves to be expressed as a mathematical wave function. When a stationary wave is applied to particles, they obey a fixed pattern, and it was the genius of Schrödinger to say that the electrons within an atom obey these rules. He developed an equation with his namesake to evaluate the behaviour of the electrons within this wave function, i.e. how the quantum states vary with space and time. He evaluated that the electron orbitals are only stable where their wave function obeyed patterns that applied to multiples of the fundamental vibration pattern, so electrons could only occupy these states. Because, of course, you can't have a fraction of a vibration. The energies go up in increasing discrete values (each with n+1 nodes), but are only stable if they obey the three-dimensional function of possible quantum state patterns. This is why they have no common difference. And wave functions that require more energy have higher frequency waves associated with the atom, which, of course, varies with the electron positions relative to others. This is why atoms with similar structures have massive differences in their chemical properties. Evidence that physics sparked modern chemistry; boom!
And there is so much more to the world of the quantum. Who would have thought that any of this was possible? Superpositions, atomic revolutions and all particles within a substance following one vector; Planck would have been awed by how far his theory took him. Where are we in this now? We're explaining multiverses, the crazy outburst of realities drawn out by Schrodinger's Cat; we're unifying quantum gravity, by explaining how exchange of gravitons occurs between quantum foam; and having found the Higgs Boson 19 months ago, work is being done to attempt to account for quantum gravity in the standard model. Let it keep us unravelling more mysteries.
Another fascinating field of physics is relativity. The relatively recent revolution devised by Albert Einstein in his spare time. He started with special relativity in 1905, where he tried to help physicists of his day with a big problem. Physicists noticed that the speed of light was the same in all circumstances. From all reference frames. Irrespective of your state of motion. But how could this be? If you move relative to a car, that car is moving relative to you at the same rate. Clearly. Light, on the contrary, is ALWAYS moving at 299,792,458m/s. So if you move away from a light source, how does its velocity relative to you remain the same? Einstein was to pinpoint the fact that no law of physics stopped time from running at different rates for you and the light source, so hey, why not? It works. And which was demonstrated with two clocks which started in phase, but showed different times after one was accelerated near light speed. Einstein was therefore able to explain that nothing can reachor exceed the speed of light, which he knew from his thought experiment running against a wave of light. When two objects move at the same velocity, they appear to be at a standstill, as they are so relative to each other. If you were moving at the same speed of light, what you would see is a periodic vibration... which isn't moving. We know it is transferring energy, but it could not be if it was not moving. So basically, as you accelerate towards the speed of light, space expands and time slows down to prevent one from reaching light speed. Trying to do so would require an infinite force, as a mass, which photons do not possess, requires force to be accelerated. And whereas increasing momentum increases velocity, its mass prevents it from reaching the energy needed to get to light speed. But an increase in momentum must equal an increase in kinetic energy, which is proportional to mass and velocity only, so if velocity won't change, mass will.
We can show that mass is a form of energy which increases with propagation near light speed if we take the relativistic doppler effect into account. Accelerating away from a light source as it loses energy by emitting light means that the light appears to be at different frequencies when observing from the two objects. Because of this, the two measured kinetic energy values differ, despite velocities being the same. The only value that could have changed must be mass, and this proof was the basis of writing out E=mc^2.
Ten years later, Einstein found a loophole in Newton's theory of gravity. In freefall, one cannot feel a force propelling one to the ground. But one is accelerating. Einstein realised that acceleration and gravity were one and the same, and that gravity is the experience of an accelerating reference frame. As with special relativity, the speed of light remains constant, so spacetime is therefore compressed in higher dimensions in gravitational interactions. so as you approach a source of gravity, time slows down. The things you see around it are running in fast forward. Objects within orbits maintain their orbits only as of inertia. And this phenomenon is what warps light coming from astronomical objects to make stars appear in different places, and at another extreme, create a black hole.
Black holes are simply an object of such great density of energy that it has such a strong gravitational spacetime compression that nothing, not even light, have the velocity required to escape from the event horizon, which may appear as a surface, where in actuality, the matter within a black hole is compressed to a singularity at the centre. As you enter a black hole, the time dilation is so immense that everything around you goes too fast to see at all, and after you cross a point where the light from behind you is orbited to your face, the tidal forces pull your matter apart like chewing gum. But if the black holes are entangled by spacetime, they may act as a wormhole; a portal through spacetime. But black holes don't last forever; Hawking radiation is the death of them. With quantum effects such as tunneling propelling particles from the event horizon, this can diminish its density and allow light to escape.
So where are we with this fascinating field of science now? Understanding quantum gravitational interactions. Gravity is a fundamental quantum interaction between quantum foam which is what drives gravity from its fundamental counterparts. The problem here is quantum loops; interactions that loop onto themselves; unlike simple electromagnetic interactions. We are yet to confirm precisely how these work, but doing so will help us evaluate probabilities of gravitational interactions; a quantum theory of gravity. It is truly extraordinary.
On the other end of the scale, we have mechanics. Mechanics which describe the motion of a mass according to acceleration, including gravity, and resultant forces. The powerful mathematics which describes the motion of objects is amazing. Which Newton first described with his simple laws of motion.
- Objects are only accelerated with a resultant force upon them
- Every action has an equal and opposite reaction
All easy by today's standards, but were the basis of all physics we use today. Without it, we would not have been able to describe anything in motion like we do, and physics would have collapsed. And the same goes for his idea of gravity, a force attracting all masses and is responsible for all structures such as solar systems and galaxies which were hard to describe otherwise. Newton alongside Leibniz also invented calculus, which, to me, is the most fascinating mathematical tool, as without it, we would not be able to express rates of change like we do today. So thank you, Sir Isaac. This describes the classical physics of basic objects, but it lead to a lot more.
Kepler was a scientist to adapt these ideas to describe the motion of planets, where he pictured orbits as having two foci; one being the body which it orbits. Which is why some orbits appear more elliptical than others. Kepler went on to describe how a planet creates equal areas underneath its orbital line within equal amounts of time, which mathematically expressed that a body in orbit moves faster nearer the source of gravity (which was also due to increased gravity and momentum conservation). He finally explained mathematically that greater orbital periods vary with greater orbital sizes, such that further-out planets are generally slower (also as of angular momentum being conserved) so a planet twice as far out takes eight times as long to orbit. Kepler went on to use these laws geometrically, which Newton used to express as his law of gravitation; in his words "Every object in the universe attracts every other object along a line of the centres of the objects, proportional to each object's mass, and inversely proportional to the square of the distance between the objects" (the last point was later found to be true for all four fundamental forces).
Another form of mechanics is that of fluids; gases or liquids. It was previously stated by Kelvin that a flying machine more dense than air was impossible. Really?
Bernoulli was a physicist who studied the motion of fluids, and noticed that fluids through tubes created more outward pressure upon the tubes with a decrease in velocity; as the force accelerating these fluids is directed against the container as opposed to the direction of motion. The pressure change was inversely proportional to the velocity change squared. Which later brought on lift; creating an upward force needed simply a shape of the body which would allow air to flow faster over it but more slowly underneath it, resulting in an overall pressure and overall force upwards, which would allow that object to be stable against gravity once airbourne. And this lead to the development of planes; whose wings are built around this principle. Without Bernoulli, we'd be eternally Earthbound.
Brownian Motion is another form of mechanics which evidenced something pretty important after thousands of years; atoms. In the 1827, Robert Brown noticed the motion of pollen grains in a pool of water, which was due to water molecules striking the grains in turn, but not balancing out the forces, therefore, the particle had this apparently random motion in zigzags across the surface. One can notice this with smoke particles in air, as the individual molecules dissipate from each other. However, Einstein took this on to say that this motion was due to atoms colliding with the molecules in turn. This was evidence that atoms existed, after thousands of years, and went on with the quantum in understanding the structure of atoms themselves, and Brownian motion itself was later seen as an example of a shape with fractional dimensions; a fractal.
There is so much more to see in physics. I would love to go on to describe some more fascinating fields of the science of it all; electromagnetism such as Faraday's work on induction from magnetic flux, thermodynamics such as how equilibria of heat run temperature to its definitions, astrophysics such as the crazy objects that are neutron stars which form at high densities such that atoms collapse into neutral clusters; and I would love to go on, but there is so much astonishing information to physics that I cannot say it all. But I'll let you go on to see them. If you don't know them, you are SO missing out. Go and unravel some universal mysteries; in two words: Die Happy.
Physics is by far my favourite of the sciences. I rest my case.
I started reading that twelve hours ago and now I have a question:
What do love abov physics again?
Phew! - Britgirl
Wow, you certainly love science! Blogs are underrated... - keyson
Science is boss, but I'm only 13 and don't understand what you posted - CityGuru
As a matter of fact, this is one of P.W. 's best written blog at thetoptens, anytime. Thank you for for this post, P.W. - Kiteretsunu
I didn't understand most of it... - Turkeyasylum
Wow. Extremely intelligently written! You'll go on to do some amazing things, that's for sure! - keycha1n
Damn, I wish I was as smart as you - Ajkloth
I live Physics too! - EpicJake
Correction: I love physics too - EpicJake
Physics is love
physics is life - GrapeJuiceK
dayum son - GrapeJuiceK
U should start physics lectures...it would help many of us like me..i mean high school students.. - visitor
I have this physics nerd at school who knows 625% things as much as me. - visitor