500 years ago, everyone thought the world was flat. One could go outside, and look at the sea or a wind-swept plain and say "of course - it looks flat, it must BE flat." A Greek scientist traveling to southern Egypt almost 1,800 years earlier had shown that the Sun was at a different angle at noon there than at Athens on the same day. He was convinced that this fact proved that the Earth was round, but the idea didn't take off, to use modern language. When Magellan's lone caraval finally made it back to Lisbon after circumnavigating the Earth east-to-west, the ship's log was inexplicably one day behind Lisbon. Everyone was certain that they had made multiple entries every day in the correct order. Hmmm.
I once flew in a Concorde from London to Dulles airport in Virginia, and from 20 miles up I can tell you that the sky is dead black at mid-day, and the horizon is noticeably curved. I BELIEVE!
That is called a paradigm-shift: everyone's idea of reality changes. Usually it means that the new explanation, or paradigm, better explains what we can observe. (But not always.)
People during the Medieval period also thought the Earth was the center of everything; the Sun and Moon rotated around it, and Man was the most important thing on the Earth. Sure looked like Earth was the center. There was a problem explaining the jinking paths of the planets, however, until Kepler and others made the convincing argument that those paths could be explained rather nicely if you just gave up the Earth-centered paradigm. Kepler and Galileo had Hell to pay as they got cross-wise with the Catholic church over this, however.
Another sloooooowwwww paradigm-shift.
In the early 20th Century, Einstein proposed first his Special Theory of Relativity, and later his General Theory of Relativity. He did this by means of a gedanken experiment - a thinking experiment. It took a long time for physicists to accept that time could slow, that light could bend in empty space, and that no frame was anchored: there was no point in the universe that you could call "fixed": or the "center" - everything was relative and just the speed of light was left fixed. Well, at least you could count on something being countable-on. When things get tough to comprehend, physicists tend to "revert" to mathematical formalisms. I can explain relativity much easier with just a few equations... much easier than trying to explain how my evil twin Jason ended up being younger than me.
This paradigm-shift in peoples' minds was quite a bit more rapid than previous shifts. Again, humankind had a new, improved version of "reality," which I'm now going to start putting in quotes.
Note to self: during a solar eclipse, light from a distant star was shown to bend. That even made the front page of the New York Times. Also, precise clocks on GPS satellites have to be carefully adjusted for the "frame drag" of relativity because of their velocity relative to the hand-held GPS device I am using to find out where I left the danged car.
In the 1920's the idea of Quantum Mechanics arose to explain "non-classical" behavior of elementary particles and light. "Non Classical" means you can't easily wrap your head around the concepts that arose: particles had characteristics of waves and vice-versa, and Heisenberg said you couldn't pin down BOTH location and momentum of a particle at the same time. An electron was not a charged particle, but instead it was actually a probability cloud wrapped around a proton - to make a hydrogen atom.
After 1945, everyone started idolizing physicists - these guys could make that mumbo-jumbo actually DO something (kill ~220,000 human beings with two bombs). Most people could easily wrap their heads around killing a lot of people and ending a protracted war. I guess we can believe the physicists from now on, eh?
But don't be in too much of a hurry here. Einstein really, really, really didn't like quantum mechanics. Sure, he could understand the math of Bohr, Heisenberg, Dirac, Fermi and others, but it just didn't... feel right to him. Einstein resisted quantum mechanics til the day he died.
Some paradigm-shifting here, but more for some, less for others.
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Let's Quick Jump to the 21st Century: the paradigm-shifts are coming fast and furious the last 40 years:
- Black Holes exist.
- Continents Drift is happening - and causes volcanoes!
- Quantum Chromodynamics (QCD) describes hadrons (including protons and neutrons) and how they behave and interact.
- Cigarettes are not good for your after-dinner digestion, but instead destroy your lungs and kill your heart and prove that you are stupid.
- Fuzzy Black Holes. Monster, Galaxy-Scale Black Holes. Black Holes that can decrease and go away over trillions of years.
- Cancer is really caused by a few stem-cells inside a tumor, not most of the cells we call "cancer."
- Complementarity - the idea that you can describe what's inside the Black Hole's Event Horizon (where you can't see anything because nothing, including light, can escape it) or you can describe the Event Horizon itself... but not both. Because they are the same thing. Got that?
Physicists are moving away from proving things with tests and experiments and back to promoting ideas like 17th Century philosophers, none of which we can ever know to be true because they can't be tested.
So, what IS "reality"? On the face of it, something we understand by organic chemistry and electrical signals in nerves and axons between our retinas, our fingers, our nose, and our brains. I'm talking about the whole inseparable nerve-brain ensemble here. Some physicists are swinging back to that old philosophical concept that we can never really know what "reality" is because of the primitive organic means we have of touching, tasting, and feeling it.
The take-away here:
First, treat anything that physicists tell you to be the truth with a 200 mg dose of healthy suspicion... because what any physicist hangs his hat on will be thrown out for a new paradigm just as sure as you and I breathe. For starts, don't take the Multiple universes ("Multiverse") idea seriously. Same holds for the fundamentally un-falsiable String Theory.
Second, don't take any ridicule for being a believer seriously. I mean come on! WHO'S doing the believing here?!??
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