My old school textbook was woefully irrelevant, incomplete, and unhelpful when it came to giving me a quick overview of the building blocks of fundamental physics. This was close to perfect though. I skipped the chapter on experimental engineering but otherwise every paragraph wrinkled my brain. Spent more time on this VSI than I normally would, and for that I am grateful. This was supposed to be a quick 1hr break in order to understand my other book on Schopenhauer using a physics lens, but now I have no idea what that other book was even saying. 2/3 steps forward, -1/3 steps back.
Notes
Why do all physicists/cosmologists working on scales that are too small or too large focus exclusively on analogies of size. Imagine the earth is this M&M I’m going to eat now, imagine the solar system is one serving size of M&Ms, like this bag, and the universe is 10^40 times that, ie the number of M&Ms I’m actually going to eat. What we need are geometric intuitions, that’s what our human-scale brain is unable to find a proper analog for. Not how large an atom is compared to the drops of water in all the oceans, that’s just as impossible, instead the arrangement of un-imaginably scaled objects visavis each other, corresponding to a geometric map of an arrangement we can indeed imagine. That’s why the Bohr model is so easy to fathom and use as a base to manipulate individual objects in the mind-map further.
Strong adhesive force between p-p or n-n balances the repulsive force of nuclear protons.
Up, down (nucleus), neutrino, electron are all that survived stably after big bang. Charm strange top bottom, and heavier electrons muon tau, vanished.
Angstrom -10 is 1 simple atom, Fermi -15 is 1 nucleus, hence used.
Sun is plasma: sea of electrons and nucleii independently, separated by the heat.
Visible light is strongest radiatio sent out by sun, that's why we've evolved to see this particular portion of the spectrum. Some really hot stars can emit gamma.
Visible light wavelength longer than size of atom, so cannot be scattered by it. X-rays larger than atom but scattered by crystals.
Multiple stones in water, troughs/peaks used to deduce where stones were dropped. Same with crystallography.
High energy particle translates to really low wavelength that can therefore see inside an atom.
Alpha radiation allowed us to see nucleus but not within. Beta radiation too weak. We need to ionise an electron and then accelerate it.
High energy electrons can thus pierce nucleus and be diverted by proton neutron within, revealing their existence
Quark is 10x mass electron. So how is 3 quark of proton = 2000x e.m? Quarks grip each other tightly, have never been separated from proton. Confined to 10^-15m, energy of 1GeV (938mev) of proton corresponds to mass 2000x.
Down slightly heavier than up. So ddu neutron little heavier, unstable than uud proton. Becomes proton through beta decay of electron, neutrino
Proton/neutron are baryons, barus heavy, barometer, baritone
Quark + antiquark couple is a meson. Annihilate quickly but like pi meson, provides attractive strong force.
Colliders more efficient than accelerators, no energy wasted on imparting motion, head on collision maximises interaction
Only 3 neutrinos because otherwise more paths for Z boson to decay and thus decay faster, which is not observed
For every charge there are 3 fundamental particles. 2/3 u,c,t quarks. -1/3 d,s,b quark. -1 e, muon, tau. 0 neutrino e,m,t. Why 3 generations (most unstable to most stable)
Microwave background radiation is 3d above absolute zero. That's it. Hear energy from annihilation of antimatter from big bang, leaving matter
Made k mesons. One in million times, observed matter and antimatter decays didn't balance. The cost and margins of new knowledge.
What really is my mass? Sum of individual atoms? 3 Quarks (30x electron mass) grip each other so tightly within confined space it becomes 2000x e.m, so it isn’t purely additive. Mass seems an unnecessary quantity here only there to massage our intuitions.
Sun-fusion all 4 forces needed: gravity pulls in Hydrogen protons until they’re colliding. Weak force transmutes proton to neutron. Strong force clumps protons+neutrons to form Helium nuclei. EM force radiates energy released.
What exactly is the charge?
Neutrino hitting water can create electron/muon that can move FTL through water, shockwave generated called Cerenkov radiation.
Force carriers: EM through photons. Strong force through Gluons (glue the protons together), and Weak through W/Z Bosons.
Neutron (ddu) transforms to Proton (udu). d->u through W-boson that decays within 10e-25s to e and neutrino. W-boson is 80times heavier than d, this ‘deficit borrowing’ is possible due to the tiny time period, limiting distance at which this force can act, hence Weak. In contrast, the Gluon and Photon are massless so perceived much stronger.
Photons can’t react with each other, they don’t themselves carry any charge, so EM dies away by inverse square distance. But Gluons do carry *color, so they cluster, strong force grows with distance such that at 10e-15, it is infinite. So impossible to pull apart the quarks of baryons/mesons.
At extreme energies, Strong, Weak and EM all become identical.
Top Quark is 180 GeV, as big as a Gold Atom, packed into just 10e-18m. So very unstable and decays before can form baryons/mesons.
P+P in plasma of sun, EM repulsion takes total energy above deuteron, so one P->N + e+ + n = 1H2. 2 of these become 2He3. 2 of these become 2He4.
Had Neutron been lighter than Proton (more stable), then we don’t get atoms and electrochemistry. Luckily, the +1 charged particle is lighter. Can it be heavier though? What gives it its charge?
Photons take 1000s of years to make it to the surface of sun because of charged plasma, but neutrinos come straight out. So studying different neutrinos gives us idea of different processes.
Big bang creates quarks and electrons. Quark form protons and neutrons which transmute into each other. Though N is heavier, with high temperature, P+e contains enough energy to become N+n. As universe cools, only N->P occurs. We get P, Deuterium universe.
After 300k years, temp is 10,000D so finally e captured by P to become neutral atoms. EM radiation is released. Transparency.
Why quarks/leptons have ½ spin? Why Bosons have unit integer spin?
Do neutrinos have non-zero mass that makes them cluster and account for dark matter?
The Higgs field interacts with particles to give them mass. Photon doesn’t interact so massless. Just like EM Radiation is bundled into quantum packets called photons, Higgs field bundled into Higgs Bosons. That is where the journey now takes me.