A good example of a physics trope is the Famous Big Bang Trope used to deduce the existence of Big Bang with an absurd extrapolation. We already knew that physics was fringe entertainment and now we see that physics actually works just like sitcoms.
There is no better example of Big Bang trope than this lecture (slides) by Risa Wechsler. Risa starts by explaining that universe-cosmos pun is a regular cycle built into cosmology. Every generation of cosmologists labels the universe of the previous generation cosmos and their own cosmos the universe.
Risa proudly discloses that Edwin Hubble was the latest cosmologist hero who showed that Milky Way was not the whole universe as cosmologists used to believe. Hubble’s discovery discarded the old cosmos made only of Milky Way and replaced it with a bigger and improved cosmos now called the universe by Risa. (8:43)
Risa herself makes clever use of the universe-galaxy pun and says that “universe is expanding” while she means “galaxies are expanding.” She repeats “the universe is expanding” so many times that she starts to believe that it is the universe and not the galaxies that are expanding. (9:17) She then mentions that Hubble found a clever way to measure the distances to galaxies. (10:06)
Please note that we are talking about “galaxies.”
Hubble measures distances to galaxies and finds a proportionality relating distances to galaxies. Everything Hubble observed is astronomical, not cosmological.
Risa says that “given this picture that the velocity is proportional to distance that implies an expanding universe.” (11:37)
How did Risa deduce “expanding universe” from “expanding galaxies?”
Well, she is a theoretical cosmologist. A cosmologist is a low level physicist who is not bound even by the loose standards of evidence of academic physics. A cosmologist is someone who can extrapolate from 50 years of observations of galaxies to 30 billion years to the beginning of the universe.
To me this is charlatanism.
Risa says, “extrapolate this expansion backwards.” Yes. Let’s do that.
Extrapolate the expansion of galaxies to a point and you’ll end up with galaxies compressed into a point. No matter how far you will extrapolate you will never get to the beginning of the universe but to a point of compressed galaxies.
Risa says, “you can basically imagine things were all a little bit closer to you, and you can extrapolate the entire expansion backwards and that’s the basic idea of the Big Bang. . . .”
Do you believe this? I don’t.
How can she extrapolate from 50 years of observations of local galaxies to 20 billion years ago?
Consider that by definition the universe is the most complicated system that there is. Therefore, the universe is more complicated than the weather on earth. Do you agree?
But with the modeling tools available to us now we are unable to model atmospheric phenomena for an extended period of time. Remember that weather is infinitely simpler than the universe.
Risa is extrapolating to 20 billion years with confidence. Where does she get this power for reckless linear extrapolation?
Well, she is a theoretical cosmologist. She shouts tropes at her audience and asks them to believe.
If you consider physics to be science then this is charlatanism. If you consider physics to be entertainment then this is irrelevant.
What do you think? Is it scientific to extrapolate to 20 billion years from 50 years of observations?