Weirdest/things that blew your mind when you learned them

[gmax137]

2. The Universe is not only expanding. The expansion is accelerating!

Or, is it?
https://phys.org/news/2020-01-evidence-key-assumption-discovery-dark.html
"New evidence shows that the key assumption made in the discovery of dark energy is in error"

 

[Filip Larsen]

My mind was blown towards positive infinity discovering how very simple (non-linear) physical systems are capable of showing surprisingly complicated forms of self-organization.

My mind was blown towards minus infinity discovering the yet unresolved Fermi paradox, especially considering the selection of possible solutions that are not so nice.

 

[DEvens]

Quantum Mechanics.

QM is pretty cool. But the "turn your head at an angle and squint" part about QM is Bell's inequality.

 

[nuuskur]

Green's theorem is the weirdest most mind¤#%& theorem I have learned about (yet). It doesn't matter how one picks $M$ or $L$, as long as they satisfy certain conditions the result holds. I don't even have the vocabulary to explain why it's so strange.

 

[jackwhirl]

I don't know the formal name, if any, but the idea that nations (or other large organizations) are 'living' things composed of humans as we are composed of cells.

 

[BillTre]

That's like ants in an ant colony (or bees or termites).
A larger emergent group composed of smaller more numerous units.

Some have said aliens might consider cities to be Earth's organisms with humans as their equivalent of our microbiome (bacteria/archaea living on or in larger creatures).

 

[Klystron]

After living and working in south Asia for years, I was astonished to learn that hot peppers (Capsicum) are indigenous to Central America and spread to Asia with the Columbian Exchange.

Hot peppers seem so essential to local cuisines and grow in such great variety in Asian agricultural regions such as the central basin in Thailand; one assumes chile peppers to be indigenous to the region or to have arrived with traders thousands, not hundreds, of years past. Live and learn, and enjoy those peppers.

 

[chemisttree]

Balut is food!
https://www.physicsforums.com/threads/the-worlds-worst-foods.87657/post-737299

 

[hodgeman]

From Undergrad, most memorable would be:
- That magnetism can be understood as charges + length contraction
- The principle of "least" action
- Dirac quantisation (before knowing some representation theory, it does look like magic..)
- The gauge principle

 

[skeptic2]

Time.

Many things have blown my mind. The first was probably a wind-up alarm clock my father gave me when I was about 6 or 7 years old. It began a fascination with time. I knew that wind-up toys go fast at first, then slow. So how could a wind-up clock possibly keep good time? My father gave it to me because it ran slower and slower and finally quit.

My father replaced it with a synchronous electric clock, something I never figured out until my teens. I immediately took the wind-up clock apart, I mean ALL apart, and cleaned it and oiled it. After I put the gears and springs back together, it worked perfectly... for a while. Meanwhile, I'd learned how the latch made it keep time by regulating the mainspring. And after finally looking at the back case, I discovered a slot with an F and S. I realized it provided access to adjust clock rate via the hair-spring. My father hadn't noticed it before and put up with inaccurate time for years. I was pretty proud of that discovery.

The latch mechanism on the wind-up allowed me to figure out how a pendulum clock regulated time in the school mimeograph room. The smell of the ink comes back to me when I remember.

The reason my free wind-up alarm clock quit was I had way over- oiled it and the open mechanism got full of dust- bunnies. I so loved the beautiful brass machinery that I'd left it open on my window sill by the bed. I took it back apart, put the parts in a small box, then went out to play. Some of the parts got lost before I got back to it. But by then I could afford a one dollar pocket watch from Ben Franklin. I could hear it tick under my pillow.

My next watch was a small water-proof Timex I got for Christmas when I was 10. I left it on while swimming just so I could tell concerned people it was water-proof and it never failed me. I had it until I accidently left it on the roof of my first car. Several reliable Timex's followed, barring misplacement.

I still have a cheap Casio left over from work. It has two time zones that I worked in and keeps military-style time to within a few seconds a month. For 20 some years I replaced various Casio's as the straps and/or batteries died. One kept time to less than a second lost per month. These cheap watches worked better than better looking quality watches I received as performance awards from work. I worked the last 20+ year's for a railroad that required accurate time.

Wes

You may be interested in this story about Eli Whitney, from https://www.asme.org/topics-resources/content/eli-whitney

The young Whitney was a natural tinkerer. Supposedly he once stayed home on Sunday, while the rest of his family went to Church, so that he could take apart his father's watch. He had it together again and working by the time they returned. He also made a violin at the age of 12. Soon after, he had started his own business forging nails and had even employed help to do so.

The version I read said that Eli had such a curiosity about how things worked, including the watch, that his family warned him time and again not to touch the watch. The watch apparently came from England and if he ruined it, it would be many months before a replacement could be gotten.

 

[Keith_McClary]

SMBC

 

[DennisN]

View attachment 255666
SMBC

I actually have experienced that, but only once, even though I have cuddled a lot with my different cats through the years. I noticed the effect in the dark when I was touching one of my cats. There were small sparks appearing between my fingers and the fur of the cat. It was a very weird and very cool experience. I can't say why I experienced it only at that particular time.

 

[gmax137]

I can't say why I experienced it only at that particular time.

I expect you live in a relatively humid place.

 

[Keith_McClary]

Is there a way to pack more than 4 disks of diameter 1 into a 2-by-2 square?

Obviously not. But is there a way to pack more than 4000 disks of diameter 1 into a 2-by-2000 rectangle?

Again, obviously not — except that there is a way! (See my essay “Believe It, Then Don’t” for details.)

James Propp's blog

 

[GJ Philp]

Hi, I figured I'd make a thread about this. What really blew your mind when you learned it or what continues to blow your mind when you think about it? I like learning really obscure mind blowing things so I figured I'd ask others about this to get some new ideas. For me it was things like uncountable/different "sizes" of infinity in real analysis, time relativity (it still blows my mind knowing most people go their entire lives not knowing time is not absolute) and currently things like fractional calculus. I think finding out you can take any order derivatives "Abusing" gamma functions and using certain integrals was ingenious. What is yours?

For me it was when I read that Alfred North Whitehead took 600 pages to prove that 1 + 1 = 2, in his enlightenment-era maths text. The it blew again when Kurt Godel showed that nothing in maths can be proven, using his clever incompleteness theorem...

 

[TeethWhitener]

For me it was when I read that Alfred North Whitehead took 600 pages to prove that 1 + 1 = 2, in his enlightenment-era maths text. The it blew again when Kurt Godel showed that nothing in maths can be proven, using his clever incompleteness theorem...

This is not even remotely what Gödel’s incompleteness theorem says. Why would you think that proving that nothing can be proven makes any sense whatsoever?

 

[TeethWhitener]

After living and working in south Asia for years, I was astonished to learn that hot peppers (Capsicum) are indigenous to Central America and spread to Asia with the Columbian Exchange.

Hot peppers seem so essential to local cuisines and grow in such great variety in Asian agricultural regions such as the central basin in Thailand; one assumes chile peppers to be indigenous to the region or to have arrived with traders thousands, not hundreds, of years past. Live and learn, and enjoy those peppers.

Tomatoes and potatoes are also New World crops. In fact, tomatoes weren't a part of Italian cuisine at all until the late 1700s.

 

[sysprog]

@Wes Tausend : 'escapement'

 

[sysprog]

This is not even remotely what Gödel’s incompleteness theorem says. Why would you think that proving that nothing can be proven makes any sense whatsoever?

Didn't Ludwig Wittgenstein (a guy whom Russell and Whitehead were ok with) explain numbers as definitional implying that 2+2=4 and show the proof and yeah he did it's in his Tractatus

 

[TaurusSteve]

Same here.
Also, whenever I try to think of the stupendously large size of the Universe it blows my mind.

This! I'm learning new things every day!

 

[BWV]

Having only a superficial understanding of both, how biology is so much more complex than any of the physical sciences.

 

[sysprog]

Having only a superficial understanding of both, how biology is so much more complex than any of the physical sciences.

In my view, biology is part of physical sciences, just as org chem is part of p chem, and p chem is part of physics.

 

[BillTre]

In my view, biology is part of physical sciences, just as org chem is part of p chem, and p chem is part of physics.

True.

And each level generates greater complexity through interactions among the elements that exist in the other levels that they are built upon.

The complexity however is mostly studied at the level at which it is found.
Physicists study the complexity of physics, chemists study the complexity of chemistry, biology studies the complexity of biology, etc...

 

[sysprog]

Well said, @BillTre

 

[Keith_McClary]

In my view, biology is part of physical sciences, just as org chem is part of p chem, and p chem is part of physics.

https://xkcd.com/435/

 

[sysprog]

Well, biology, physics, chemistry, whatever; I'm a boy person (old enough to have started to be in my 60s), and I think that (fully-grown) girls rule, wherefore, whatever they say, right?

 

[BWV]

Also the 90-95% population declines in the Americas from the introduction of European diseases. Most native Americans who died in this never saw a European, and when the Europeans did move inland, they thought they had found a pristine wilderness which in fact was just a result of the collapse of the indigenous populations that had actively managed the land for centuries.

 

[sysprog]

Also the 90-95% population declines in the Americas from the introduction of European diseases. Most native Americans who died in this never saw a European, and when the Europeans did move inland, they thought they had found a pristine wilderness which in fact was just a result of the collapse of the indigenous populations that had actively managed the land for centuries.

Really? They "managed the land for centuries"? That looks like 'noble savage' nonsense to me -- after they resorted to crossing the ice-age land bridge they maybe were hungry and didn't forget to extinctionate the wooly mammoth while they were on their way to the Southern end of the so-called 'Americas' -- what is now called Peru.

 

[Keith_McClary]

Southern end of the so-called 'Americas' -- what is now called Peru.

https://en.wikipedia.org/wiki/Fuegians

 

[BWV]

Really? They "managed the land for centuries"? That looks like 'noble savage' nonsense to me -- after they resorted to crossing the ice-age land bridge they maybe were hungry and didn't forget to extinctionate the wooly mammoth while they were on their way to the Southern end of the so-called 'Americas' -- what is now called Peru.

It’s science, nothing else. Looks like you maybe are the one with an agenda

https://www.theatlantic.com/magazine/archive/2002/03/the-pristine-myth/303062/

https://www.sciencedaily.com/releases/2011/03/110321134617.htm

 

[bhobba]

By simply using Euler's formula how easily the formula for capacitors, inductors, resonance etc is explained. Then came the granddaddy of them all - Noether's Theorem - that is just so beautiful, but strange, and the most convincing evidence I know of that god (however you conceive of him/her) exists. At first I was amazed at Godel's Theorem, but later understood it was just Cantors diagonal argument in disguise - a tricky use of it - yes - but it's still the crux:
http://www.math.hawaii.edu/~dale/godel/godel.html

Thanks
Bill

 

[scottdave]

That phase velocity can travel much faster than the "thing" (wave, particle beam, etc) that created it - for example, an electron beam trace on a Cathode Ray Tube can "travel" faster than light! Yet nothing is violated.

Gyroscopic precession took me awhile to wrap my head around.

 

[collinsmark]

Gyroscopic precession took me awhile to wrap my head around.

(Source: https://xkcd.com/332/)

 

[NTL2009]

... Gyroscopic precession took me awhile to wrap my head around.

I'm not a physicist, and until this moment I hadn't realized that I never really thought about the why/how of a gyroscope. I've only understood that it does what it does (like gravity).

I'm afraid I might hurt my brain if I tried, so I'll go on with life just admiring it. If one day, one of my grand-kids ask "Why", maybe I'll have him/her post here!

 

[collinsmark]

I'm not a physicist, and until this moment I hadn't realized that I never really thought about the why/how of a gyroscope. I've only understood that it does what it does (like gravity).

I'm afraid I might hurt my brain if I tried, so I'll go on with life just admiring it. If one day, one of my grand-kids ask "Why", maybe I'll have him/her post here!

Years ago I bought a book on Lagrangian mechanics specifically because I was interested in wrapping my head around gyroscopes. It didn't necessarily work, but it did get me to appreciate Lagrangian mechanics.

 

[sysprog]

https://en.wikipedia.org/wiki/Fuegians

You're right; I forgot about Chile, too . . .

 

[osilmag]

Time Dilation

 

[Swamp Thing]

A few years ago I read a book on prime numbers by Marcus du Sautoy. That's where I learned one of the most amazing ideas I've ever come across -- that the zeros of the Riemann Zeta Function contain information that you can use to list out all the prime numbers.

 

[sysprog]

A few years ago I read a book on prime numbers by Marcus du Sautoy. That's where I learned one of the most amazing ideas I've ever come across -- that the zeros of the Riemann Zeta Function contain information that you can use to list out all the prime numbers.

Those methods are even more inefficient than the sieve of Eratosthenes.

 

[Klystron]

Those methods are even more inefficient than the sieve of Eratosthenes.

True when one measures computation complexity. Teaching sieve techniques to students gives insight into the processes of multiplication and division using only an integer list, simple counting and elimination.

In most basic form the students take prime number 7, count seven places and eliminate 14, already marked as a multiple of 2, progress to 21, etc.; learning common factors, multiplication and division plus counting skills. Rather profound for a simple exercise.

A few years ago I read a book on prime numbers by Marcus du Sautoy. That's where I learned one of the most amazing ideas I've ever come across -- that the zeros of the Riemann Zeta Function contain information that you can use to list out all the prime numbers.

Good for you. I try to read books about mathematics whenever I encounter them. As history books need accurate maps, math books require formulas, functions and graphs for understanding. Last few years I have read two fascinating books on solving/proving Fermat's Last Theorem, two about the number zero, and several books about integers including an exhaustive history of numerical symbols.

 

[sysprog]

Your post #90 in this thread was in my view an especially nice post @Klystron.

 

[pleeb]

Years ago I bought a book on Lagrangian mechanics specifically because I was interested in wrapping my head around gyroscopes. It didn't necessarily work, but it did get me to appreciate Lagrangian mechanics.

Color doesn't exist. Only the totally color blind see the world as it really exists. Maybe that's why B&W photography is so fascinating.

 

[sysprog]

Years ago I bought a book on Lagrangian mechanics specifically because I was interested in wrapping my head around gyroscopes. It didn't necessarily work, but it did get me to appreciate Lagrangian mechanics.

Color doesn't exist. Only the totally color blind see the world as it really exists. Maybe that's why B&W photography is so fascinating.

In my non-colorblind view, this is nonsense; color is part of the visual information; that's why our retinas have cones, along with all those rods.

The point that @collinsmark raised regarding gyroscopes and Lagrangian mechanics has nothing to do with color or black-and-white vision. It was about the development of his intellectual vision by his being appreciative regarding something newly learned. That seems to me to be on-topic in this thread.

Your preference for 'noir et blanc' may be worthy of expression, but was not responsive to the post that you quoted.

 

[Merlin3189]

I can't remember exactly when I learned about shunt wound motors speeding to destruction when they lost their field current. May not have blown my mind, but I was pretty sceptical and took a lot of convincing.

I'm reminded by it's popping up in a thread today with someone else who can't believe it.

 

[pleeb]

In my non-colorblind view, this is nonsense; color is part of the visual information; that's why our retinas have cones, along with all those rods.

The point that @collinsmark raised regarding gyroscopes and Lagrangian mechanics has nothing to do with color or black-and-white vision. It was about the development of his intellectual vision by his being appreciative regarding something newly learned. That seems to me to be on-topic in this thread.

Your preference for 'noir et blanc' may be worthy of expression, but was not responsive to the post that you quoted.

You're quite correct, we have cones that give us the illusion of color. But nothing is actually colored. We simply interpret shades of gray as color. There is only light and the absence of light to various degrees. Are you a tetrachromat?

 

[BillTre]

You're quite correct, we have cones that give us the illusion of color. But nothing is actually colored. We simply interpret shades of gray as color. There is only light and the absence of light to various degrees.

Well, only grey scales of different frequencies (which are real), which the brain codes as different colors (to represent that reality).
The fact that natural selection has selected for these mechanisms gives credence to that reality as well as its significance to the organism's survival.

 

[sysprog]

You're quite correct, we have cones that give us the illusion of color. But nothing is actually colored. We simply interpret shades of gray as color. There is only light and the absence of light to various degrees. Are you a tetrachromat?

That's just plain wrong. @BillTre beat me to it, but color perception is not just grayscale being interpreted as color. For example, there's a real and measurable difference between infrared and ultraviolet light even though we can't see either of those. I imagine that you don't suppose that the differences between the frequencies of EMR from your lightbulb and those that cook your food in your microwave oven are merely grayscale variation illusions.

 

[Dr_Nate]

I like to show my students a visible spectrum and ask them to point out where the color white is. Then I show them that their minds are tricking themselves(?) by using a handheld spectroscope and looking at the emission lines from white fluorescent lights.

 

[Dr_Nate]

From walking my dog at night, I learned that I can tell from a distance whether the colour from xmas lights are made from two different LEDs or not, or whether a car's brake lights are incandescent or an LED. I think it has to do with persistence of vision and the pulse rate of LEDs.

I just flutter my eyes back and forth. For brake lights, I can see dots for the LEDs and a line of red for the incandescent. I never took apart someone's brake lights to truly confirm it, but I think it's true because I think I tell the difference normally. For the xmas lights I see dots of different colour that when added together would produce the colour I normally see.

 

[Keith_McClary]

I just flutter my eyes back and forth.

Jocelyn Bell Burnell, who co-discovered the first pulsar PSR B1919+21 in 1967, relates that in the late 1950s a woman viewed the Crab Nebula source at the University of Chicago's telescope, then open to the public, and noted that it appeared to be flashing. The astronomer she spoke to, Elliot Moore, disregarded the effect as scintillation, despite the woman's protestation that as a qualified pilot she understood scintillation and this was something else.