In modern physics, antimatter is defined as matter composed of the antiparticles (or "partners") of the corresponding particles in "ordinary" matter, and can be thought of as matter with reversed charge, parity, and time, known as CPT reversal. Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Minuscule numbers of antiparticles can be generated at particle accelerators; however, total artificial production has been only a few nanograms. No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling.

In theory, a particle and its antiparticle (for example, a proton and an antiproton) have the same mass, but opposite electric charge, and other differences in quantum numbers.

A collision between any particle and its anti-particle partner leads to their mutual annihilation, giving rise to various proportions of intense photons (gamma rays), neutrinos, and sometimes less-massive particle–antiparticle pairs. The majority of the total energy of annihilation emerges in the form of ionizing radiation. If surrounding matter is present, the energy content of this radiation will be absorbed and converted into other forms of energy, such as heat or light. The amount of energy released is usually proportional to the total mass of the collided matter and antimatter, in accordance with the notable mass–energy equivalence equation, E=mc2.

Antiparticles bind with each other to form antimatter, just as ordinary particles bind to form normal matter. For example, a positron (the antiparticle of the electron) and an antiproton (the antiparticle of the proton) can form an antihydrogen atom. The nuclei of antihelium have been artificially produced, albeit with difficulty, and are the most complex anti-nuclei so far observed. Physical principles indicate that complex antimatter atomic nuclei are possible, as well as anti-atoms corresponding to the known chemical elements.

There is strong evidence that the observable universe is composed almost entirely of ordinary matter, as opposed to an equal mixture of matter and antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics. The process by which this inequality between matter and antimatter particles developed is called baryogenesis.

Antimatter particles carry the same charge as matter particles, but of opposite sign. That is, an antiproton is negatively charged and an antielectron (positron) is positively charged. Neutrons do not carry a net charge, but their constituent quarks do. Protons and neutrons have a baryon number of +1, while antiprotons and antineutrons have a baryon number of –1. Similarly, electrons have a lepton number of +1, while that of positrons is –1. When a particle and its corresponding antiparticle collide, they are both converted into energy.

Megathreads and spaces to hang out:

reminders:

Links To Resources (Aid and Theory):

Aid:

Theory:

  • VHS [he/him]
    ·
    2 years ago

    A lot of that is to blame on the Hays Code and the vertically integrated studio system, they really were making a lot of formulaic slop in a similar way to today. Still some good shit here and there, but the end of the 60s into the 70s let directors get a lot more creative in the US.

    A lot of the films I like from the 60s are Italian cinema, such as spaghetti westerns, Italo-horror, and classic dramas like La Dolce Vita and L'Avventura. Great leftist films The Battle of Algiers and Z were from the 60s too. As far as US films go, I think most of Hitchcock's work was pretty good, and there were some solid film noirs in the 40s and 50s.

    • Cromalin [she/her]
      ·
      2 years ago

      the good the bad and the ugly is outstanding, one of the greatest movies ever made. and obviously you have directors like kurosawa or kubrick (dr strangelove is his best film imo) and orson welles is famous for a very good reason

      • VHS [he/him]
        ·
        2 years ago

        Definitely some of the greats, hard to give them all enough credit in one comment

      • Frank [he/him, he/him]
        ·
        2 years ago

        Woah, careful you don't cut yourself on that edge! ; )

        Srsly though, it's as much important to watch Hitchcock just to understand where he innovated so that others could build on his ideas. I use Halloween as an example of this in film a lot - Halloween might seem cliched and formulaic to a modern viewer because it originated many of the elements of horror movies that later became cliches and formulas. Likewise Hitchcock was responsible for many tropes that were solidified in later thrillers.

        • weeping_angel [comrade/them]
          ·
          2 years ago

          Yes yes I was going to invoke the Seinfeld-referencing version of that idea but thought better of it

          Whats ur favourite Hitchcock? I like Birds so I can cheer for the birds

          • Frank [he/him, he/him]
            ·
            2 years ago

            Honestly I think The Birds is the only one I've seen in full. I have this weird thing where I get a lot of knowledge from reading piles of second hand sources. Like most of what I know about Hitchcock is from reading discussions about him and his movies, not from actually seeing the movies. I've been having a really hard time with visual media the last few years. Some combination of ADHD and trauma is making it really hard to watch a movie for more than a few seconds at a time, but with text I can bounce back and forth between different things and gradually get through an article. : p