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Ask HN: What is a science fact that blew your mind when you learned it?

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Re: Ask HN: What is a science fact that blew your mind when you learned it?

#91

When i could "see" my visual blindspot. https://lasikofnv.com/try-these-3-fun-tests-to-find-your-vis... .

OMG me too. I was having an eye exam. The technician had a black field with a bunch of lines. Holding a rod with a white dot, and told to let them know when it disappeared.

I laughed, "Well that will only happen if you put it behind your back."

They laughed, "Everyone has an astigmatism where the nerves enter the eye. We are looking for that or any other issues."

I was so shocked when the dot disappeared.

Also happy to hear it was the normal blind spot.

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#92
BTW, "it takes a photon over 100,000 years to exit the Sun" is misleading - it sounds like there's a single photon that's generated deep inside the Sun's core and winds its way through like a cicada until it emerges at the surface.

In reality, any photon traveling inside the Sun will almost instantly collide with some other particle, which may emit zero, one, or more photons as a result. When we say "100,000 years", I believe we're summing up the total of these photons' expected lifetimes, basically following the flux of energy rather than individual photons.

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#94
I absolutely cannot psychologically deal with the Monty Haul paradox. https://en.wikipedia.org/wiki/Monty_Hall_problem I've coded it multiple times in multiple programming languages as a cathartic exercise. Despite seeing the results obviously printed out in a console in front of me, I just can't handle it. I lose SAN just thinking about it.

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#96
post #90

Earlier quoted context omitted.

What level of drinking would cause this, though?

Come over to my house and I'll show you... That's why haven't had a drink for the last 5 years

Well, i just meant i had not heard this - so i was curious if a glass of wine a night causes damage.

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#97
post #46

The dual slit experiment. Run the experiment with no one watching it, it produces result A. Run it again and watch it, it produces result B. Watching the experiment changes the result. WTF????

It's false information. It's debunked multiple times. "Watching" means "placing or turning on an additional detector", which ruins interference pattern. To develop intuition, look at double slit experiment made at macro scale using walking droplet.

I'd really appreciate a few links to this. I am on a youtube binge lately watching quantum dynamics lectures for lay people. The constant talk about "watching" and "observers" drives me crazy. I refuse to believe anything has anything to do with whether or not anybody is "watching" anything. Bouncing photons off of it? Sure I can see how that would affect all sorts of things. But if the bouncing photons alter what's going on (and it seems they cause as much quantum decoherence as anything else might) then that's not the same thing as just "watching". That word implies to me "there are ambient photons or some other field or background that does not alter the experiment, and I am merely observing that background to get an idea what's going on within the experiment". If the experiment cannot be conducted without interference within an ambient background of photons flying around, or within some other medium we passively non-destructively-to-the-experiment observe, then we cannot currently be said to be "observing" anything at all with respect to that experiment. Let's just say that, can't we? If we can't not alter the relevant circumstances of what's going on, then let's just admit that, without using faulty and improper language to "describe" what's happening. Can somebody help me out with this?

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#98
look at the time-lines of the universe and some of the entries, especially the last few, are mind blowing ( https://en.wikipedia.org/wiki/Timeline_of_the_far_future )

e.g.

"Due to the gradual slowing down of Earth's rotation, a day on Earth will be one hour longer than it is today"

"From its present position, the Solar System completes one full orbit of the Galactic Center"

"All the continents on Earth may fuse into a supercontinent (Pangaea Ultima, Novopangaea, or Amasia)"

"Tidal acceleration moves the Moon far enough from Earth that total solar eclipses are no longer possible."

"the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed "Milkomeda" ... There is also a small chance of the Solar System being ejected. The planets of the Solar System will almost certainly not be disturbed by these events"

"time until stellar close encounters detach all planets in star systems (including the Solar System) from their orbits"

"time until those stars not ejected from galaxies (1–10%) fall into their galaxies' central supermassive black holes. By this point, with binary stars having fallen into each other, and planets into their stars"

"estimated time for rigid objects, from free-floating rocks in space to planets, to rearrange their atoms and molecules via quantum tunneling. On this timescale, any discrete body of matter "behaves like a liquid" and becomes a smooth sphere due to diffusion and gravity"

"... they [Positrons] find a distant electron to pair with and the two enter into a highly excited state of positronium, with a radius larger than the current universe. Over the next 10^141 years they will gradually spiral inwards until they finally annihilate"

"time until a supermassive black hole with a mass of 20 trillion solar masses decays by Hawking radiation ... marks the end of the Black Hole Era. Beyond this time, if protons do decay, the Universe enters the Dark Era, in which all physical objects have decayed to subatomic particles"

"... time for all nucleons in the observable universe to decay ..."

"... estimated time until all baryonic matter in stellar-mass objects has either fused together [into iron-56] ... or decayed from a higher mass element into iron-56 to form an iron star"

"Estimated time for a Boltzmann brain to appear in the vacuum via a spontaneous entropy decrease"

"estimate for the time until all iron stars collapse into black holes ... which then (on these timescales) instantaneously evaporate into subatomic particles ... Beyond this point, it is almost certain that Universe will contain no more baryonic matter and will be an almost pure vacuum until it reaches its final energy state ..."

"Because the total number of ways in which all the subatomic particles in the observable universe can be combined is a number which, when multiplied by , disappears into the rounding error, this is also the time required for a quantum-tunnelled and quantum fluctuation-generated Big Bang to produce a new universe identical to our own ..."

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#99
post #76

Not a fact per se, but: the sheer amount of living things that came before me, in the sense of my direct ancestors and their direct ancestors etc. etc – not only my human ancestors, but the whole of my ancestors all the way back to the origins of life itself – and I would not be here today if even one of them would have died before reproducing... that manages to blow my mind every single time I think about it.

Try counting the total number of your ancestors: you have 2 parents, they have 4 parents in total etc., i.e. 2^N where N is the number of generations. Going just 40 generations back (about 1000 years), you had 2^40 = 1,099,511,627,776 ancestors.

But not necessarily 2^40 unique ancestors. That is, the same person may be your ancestor by more than one route through the subsequent generations.

Re: Ask HN: What is a science fact that blew your mind when you learned it?

#100
post #32

Earlier quoted context omitted.

Don't know exactly why, but thinking about the vastness of the universe always cheers me up. Thanks for sharing :)

Relatedly, my dad always told me that thinking about the vastness of the universe "weirded him out." My hypothesis is that he has narcissistic tendencies so pondering the vastness of the universe only highlights his own insignificance. I've noticed similar reaction from people who visit a large city for the first time and get a sense of how small they are in the grand scheme.

Reminds me of the Total Perspective Vortex from Hitchhikers Guide to the Galaxy, which exposed an individual's insignificance in the universe.
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