We all have a concept of reality. We know what is “fact” and what isn’t. However, the truth of the matter is that the definition of “real” is a mere construct of the brain.
If that didn’t blow your mind, this list has a lot more where that came from. These are responses from a recent Reddit thread, bearing a question originally directed at scientists: “What’s something we know is true but people don’t realize how crazy it is?”
A lot of these answers did not disappoint. You may want to have Google open next to you as you read through, since you’ll likely want to do a little more digging.
#1
Your brain can’t feel pain. Surgeons can operate on it while a patient is awake.
Image source: Cautious-Sail-7068, AirImages
#2
Your stomach lining regenerates every few days. Otherwise stomach acid would literally digest your own organs. You’re constantly saving yourself from yourself.
Image source: ButteryMashedPotaton, Kohanova
#3
About 99.86% of all the mass in the solar system is inside the sun.
Everything else combined–all the planets, moons, asteroids, comets, kuiper belt objects, oort cloud objects–is a rounding error compared to the sun.
The Earth has about 0.0003% of the solar system’s mass. We are decimal dust.
Image source: PerpetualMotion81, Mohamed Nohassi
#4
Charles Keeling had a team at Mauna Loa Observatory taking twice-daily samples of the air since 1958, specifically to test for CO2. As you can imagine, this was was done by a dude bringing a jar out, holding their breath, opening the jar, waving it around, putting back on the lid, then resuming their breathing. Every day, twice a day.
The technology for testing these samples for the different isotopes and exact measurements that are actually useful was invented and brought to the island in 1978.
Let that sink on. They collected jars of air for 20 years before they actually had a way to test them properly, and did it every day, twice a day.
All good scientists are mad scientists, the crazier, the better.
Image source: Newsmemer, reddit
#5
After being a Behavioral Specialist for so long it is astounding how much of human behavior is built on wanting attention from others. Even me just writting this, the primary motivation would be to gain attention and demonstrate my knowledge. Sure I just want to share but even that is rooted attention seeking behavior. At first it’s a little disturbing realizing that non of us can escape it. But it’s part of being human. We are wired to be this social and it has helped us to survive.
Image source: WilliamoftheBulk, inkevych_D
#6
Mushrooms are closer to animals than to plants. In fact, in our current phylogenetic classification, fungi are even closer to animals than to slime moulds.
Image source: AztraChaitali, Hans Veth
#7
I’m personally a big fan of relative size of things. If you were to stretch out all of the DNA in a single cell, it would measure 2 meters or 6.5 ft! On a more macro scale, the surface area of human lungs is equivalent to a tennis court.
I have a PhD in molecular biology and worked as a professional protein biologist for a bit. I miss it, but my health was declining and my brain and hands just aren’t built for fast-paced science anymore (shoutout to MS!)
Image source: missprincesscarolyn, digitale.de
#8
The earth is only about 20 galactic years old. Meaning it has only completed 20 full orbits around the galaxy.
Image source: big_redwood, NASA
#9
The atoms in your body are older than the Earth.
Most of them were formed inside exploding stars billions of years ago.
You’re literally recycled stardust walking around arguing about WiFi speed.
kranools:
Is this why I feel so tired?
Image source: Official_waIter, Getty Images
#10
You are about 1cm taller in the morning than at night, as your spine compresses throughout the day.
anon:
Not really the spine itself, but the thickness of the spine’s intervertebral discs decreases from compression.
Slice5755:
Top tip for men: Record your height for Tinder at 6 o’clock in the morning.
Image source: GiveUp-WatchItBurn, bruce mars
#11
PET scans sound straight out of scifi.
We inject a specific radioactive tracer into your body. The isotope emits positrons (literal antimatter) as it decays. The positrons interact with electrons in your body and annihilate creating gamma ray bursts and we are able to track that light/energy to create a detailed 3D map of your body.
We use antimatter everyday to help save lives.
Image source: ProjectCoast, reddit
#12
Your brain made up the entire experience of “reality.”
You’ve never actually seen color, felt texture, or heard sound the way they truly exist. Your brain just translates electrical signals into a fully immersive simulation and goes, “yeah this seems real.”
You are a consciousness piloting a meat suit, trusting a 3-pound organ that hallucinates your entire world in real time… and we all just accept that like it’s normal.
Image source: NikitaG00, Martin Sanchez
#13
The microbiome .. the sheer number of bacteria we carry on and within ourselves.
Image source: Yeppie-Kanye, maxxyustas
#14
Your brain makes unconscious decisions up to 10 seconds before you are conscious of those decisions.
>Groundbreaking research reveals how unconscious decisions are made in the brain seconds before you are aware, challenging our long-held beliefs about free will.
>Our subjective sense of making a free choice might be an illusion generated after the fact.
>Scientists could predict a person’s decision from their brain activity up to 10 seconds before the person was consciously aware of it.
>By the time you believe you are making a choice, your brain’s unconscious processes may have already determined the outcome.
>The experience of making a choice feels immediate and personal. From deciding what to eat for breakfast to which button to click on a website, we perceive ourselves as the authors of our actions. But a groundbreaking study challenges this intuition, suggesting our brain makes unconscious decisions long before we are aware of them.
In a 2008 research, published in Nature Neuroscience, by Chun Siong Soon and his colleagues found that the outcome of a decision can be predicted from brain activity up to a full 10 seconds before it enters conscious awareness.
Image source: CriticalPolitical, Andrej Lišakov
#15
Some algae species (phytoplankton) are microscopic and they are capable of producing oxygen. Making them more efficient than trees at that role.
Image source: FrequentTown3, Getty Images
#16
For decades we have known that 2 tricks to help you lucid dream are looking at your hands or trying to read text because dreams don’t do hands or text well and can be clue that you are in a dream.
Why the hell are dreams and AI suffering from the same glitch?!?
Image source: crujones43, Bruce Christianson
#17
Honestly, all of it is totally crazy. E.g.:
Our sensory systems convert light (radiation) or sound (vibrations) etc. into electricity and chemical reactions that allow us to perceive the world. You can’t tell me that’s not weirder than sci-fi.
LEDs: we transport electrons through crystals and they glow. Sounds totally fake.
And the list goes on and on. .
Image source: TheChrisLick, reddit
#18
The amount that your body’s microbiome affects you. Studies have shown that reduced cravings for alcohol were achieved after fecal transplants. Also we are about 1:1 Human cell and microbe.
Image source: Useful-Passion8422
#19
Fly around the surface of Earth once non-stop in a 747?
It would take around 2 days.
Fly around the Sun once non-stop in a 747?
Around 6 months.
Fly once around the largest star discovered in a 747?
1,200 years.
Fly across the Milky Way once in a 747?
120 billion years.
Image source: maybethen77, Justin Hu
#20
I learned that the metric our brain use to tell our body to breathe is not how much oxygen is coming in, but by the amount of carbon dioxide in our body. So if we enter an area that has no oxygen and very low carbon dioxide our body wouldn’t know we’ll just pass out and pass away.
Image source: Wiseguy_7, Darius Bashar
#21
All the planets, aligned properly, can fit between in Earth and our Moon.
Image source: royalpyroz
#22
The Earth is nuclear powered.
The core contains far and away the majority of radioactive isotopes on (in) Earth. Part of what keeps the mantle molten is this radioactivity. Without it, it would have solidified already, throwing a wrench into all kinds of Earth systems.
Interesting, Lord Kelvin attempted to estimate the age of the Earth via cooling. He assumed the Earth began as molten, which is true. The calculated how long it would take an Earth-sized body of molten rock to cool to modern surface temperatures. He estimated between 20 and 100 million years. The main error in his calculation is due to radioactive decay.
Image source: Illustrious_Map_3247
#23
The universe isn’t really 3D space, but 4D spacetime. That’s one unified geometric structure, containing ALL events, at EVERY place and time. What we call “now” is not a universal slice shared by everyone. Different states of motion correspond to different slices through that structure, and therefore to different notions of simultaneity.
A simplified analogy is an animator’s flipbook. It doesn’t make sense to ask what a character is doing “right now” while the book is just sitting on the shelf, because everything the character ever does is already contained within it. To talk about what is happening “now,” you first have to choose a page. Once you do, you can describe what the character is doing on that slice. But choosing one page does not mean the others do not exist, nor does it mean another observer could not choose a different page as their “now.”
The reality is actually even weirder because slicing at different angles puts different events at different times for different observers, even after compensating for signal delay, and events that aren’t causally connected have no absolute time ordering at all.
Image source: Hexxys
#24
For 186 million years, giant reptiles absolutely dominated the planet, on land, in the sky, and in the rivers and oceans, until a single asteroid ended it all. Extinction events are usually more complex or drawn out over thousands or millions of years, but the one that happened 66 million years ago was caused by a single extremely rare event that happened on one random day. One space rock hitting a shallow part of the Gulf of Mexico caused almost every animal larger than a wolf to become extinct, worldwide, within a few months. It’s the only mass extinction event that was truly instantaneous in a geological sense, and it ended one of the most diverse and spectacular ecological eras in Earth’s history.
Image source: Aaron696
#25
Your eyes can send way more data than your optic nerve can carry. We don’t know how your eyes decide what data to send and what data to ignore.
There doesn’t seem to be any sort of decision-making cells or structures, and it’s not something as simple as “movement more important” or “brighter more important”.
Image source: 6a6566663437
#26
Consider the ridiculousness of modern chip making technology: 25000 tin droplets per second exploded into plasma while falling, by not one or two but three strikes in a row from infinitely precise lasers that could hit a pebble on the moon from earth, reflected off mirrors so smooth that if they were earth sized the largest bump would be a millimeter, to produce wafers grown from a single atom of silicon to be perfectly symmetrical with 40000 transistors for each width of a human hair all in a sealed container with gas pumped at 300kph through it.
There is exactly one company in the world that has been able to achieve this and they supply the entire world’s demand for high performance chips.
Image source: LeucisticBear
#27
Every breath you take today likely includes at least one molecule once exhaled by julius caesar when he passed away.
how?
because the atmosphere thoroughly mixes over time and each breath contains an enormous number of molecules– ~1 × 10²² molecules.
but it can get even more interesting. due to the number of molecules in our atmosphere and those in each breath and given enough time, every breath you take likely includes a molecule of air once breathed by….
– taylor swift at that concert a few of years ago
– w. shakespeare
– medieval peasants
– cleopatra
– Jesus of nazareth
– wooly mammoths
– and even dinosaurs
want to blow your mind even more?
every time you drink a glass of water, at least one molecule of that h2o likely passed right through a dinosaur.
Image source: 3nails4holes
#28
Certain colours like magenta don’t actually exist in reality—-we’re just not built to deal with the multiple wavelengths of light ‘magenta’ pings back to us so our brain goes ‘here’s magenta- that’ll do’.
Image source: hadawayandshite
#29
There are more trees on Earth than stars in the Milky Way.
Image source: GrowthStackLabs
#30
Birds, mammals, reptiles and amphibians are all tetrapod fish. An organism cannot evolve out of a clade (on a smaller scale, the same as the fact that birds are dinosaurs – they descend from the most recent common ancestor of * Megalosaurus* and *Iguanadon* and are therefore dinosaurs). Basically everything animal is technically a fish and even has gills in the early stages of development.
Image source: jayellkay84
#31
Spiders eat more biomass weight each year than the combined weight of all of the humans on earth, up to 800 million metric tons. Spiders eat more biomass than all of the whales in the oceans eat.
They are almost certainly the most important predator on earth.
Image source: Iamthewalrusforreal
#32
Black holes warp both space and time the closer you get to it. When you cross the event horizon, space and time become so warped they actually switch places.
Image source: jadefire03
#33
I am turning 46 this year. I have a kid in middle school still.
Exoplanets weren’t confirmed to exist until I was 12. When I was 11 the world thought we were possibly/probably the only planet in the universe that could harbor life.
I still have all my hair and think I’m pretty hip. If you are young right now, consider how little we actually know about life and the universe. We know nothing at all yet. We are so incredibly far from mastery.
Image source: Sputniksteve
#34
Https://en.wikipedia.org/wiki/Deep_hypothermic_circulatory_arrest
TL;DR we can cool a person’s body temperature down to about 18°C/64°F and stop their blood flow completely for certain surgical procedures. Often times, blood flow to the body is stopped but we can still maintain blood flow to the head, AND we can even pump blood backwards through the brain (into the veins and out the carotids) for a while.
After the parts requiring no blood flow are done, we can restart blood flow and warm the person back up to a normal temperature and it’s as if nothing happened.
Image source: Randy_Magnum29
#35
Oncology scientist. Pharmaceutical companies are not hiding the cure to cancer. Whoever finds the cure to cancer will be bring too much value to the shareholders for it to be squashed.
Image source: 42yy
#36
Plain old water has one of the highest heat capacities in chemistry. It also has one of highest heats of vaporization of most liquids. This allows water and steam to be carriers of vast amounts of energy.
Image source: UniqueAd7770
#37
“The fact that atoms are 99.9999999% empty space. If you removed all the ’empty space’ from the atoms that make up every single human being on Earth, the entire human race—all 8 billion of us—would fit inside the volume of a single sugar cube. We feel solid because of electromagnetic fields pushing against each other, but in reality, we are essentially just ‘organized nothingness.’ You aren’t actually ‘touching’ the chair you’re sitting on right now; your electrons are just repelling its electrons so strongly that it creates the illusion of a solid surface.”.
Image source: Miserable_Vacation88
#38
Farmer here. Seems obvious, but just how many resources nature has to throw at EVERY problem (in this context, “problem” means your healthy crop).
Our solutions for pest / disease issues on crops are incredibly specific. Develop a specific insecticide that targets the digestion of a gnat, or the reproductive cycle of a worm. Nature has 24/7 to develop infinite new evolutions of that pest / disease that will circumvent your incredibly specific mode of action.
Follow up – no…nature WONT “just provide for us”. Nature will provide for itself. All the crops we eat have been developed by humans to feed us. If you ever doubt that, look up the native species we derived corn or apples or strawberries from. They look nothing like the crops we enjoy today.
Image source: randobot456
#39
The ice water you get at a restaurant is colder than the water at the bottom of the Marianas trench.
The deep sea is surprisingly warm- about 40 F. Because that’s the temperature water is densest at.
Image source: guyscanwefocus
#40
Because of the finite speed of light, you only ever see the past and you only can affect the future. You don’t live in the present, it’s completely walled off from you and is not even a physically well defined concept.
CoderJoe1:
By the time your brain registers what’s happening, it’s already in the past.
Image source: fuseboy
#41
An ELI5 one: (I think, does a 5 year old know repel, protons, fusion? hmmm…)
The sun works by getting protons (or hydrogen) close enough that they ‘stick’ (nuclear fusion) which releases the energy that powers the sun.
Protons repel like north poles of magnets and you have to get them going really fast to get them close enough to stick (like magnets covered in superglue). The hotter the sun, the faster the protons move around. The sun is not hot enough to make protons move fast enough to stick and almost no fusion should happen in the sun.
The only reason it does is because the proton isn’t a solid particle like a marble. Place a proton on the desk and theres a small chance you’ll find it slightly to the left or right of where you think you placed it. The further it ‘jumps’ from where you put it, the smaller the probability that its there when you look for it.
So when two protons bang together as close as they can get (which isn’t close enough to stick) – there is a small probability that one of them isn’t where it ‘should’ be, but is closer to the other proton – close enough to stick.
This small percentage of collisions that work when they shouldn’t match the power output of the sun.
The sun is powered (and all life only exists) because of black magic trickery (otherwise known as quantum tunnelling).
Image source: Dojustit
#42
Before Big Bang inflation, time and space were most likely jumbled together in a non-orientable surface. Which is to say, the flattening of space through exponential expansion is the only thing that gave time any sense of direction, and that direction may have been selected completely randomly. There was no such thing as a time before the Big Bang.
Image source: Funny-Vegetable-1024
#43
Humans evolved to crave fatty foods as a survival strategy. Since our hunter and gatherer ancestors never knew when they would get their next meal, possibly days or weeks, finding a big fatty meal was a lifesaver. But nowadays you can get a double bacon chilicheeseburger combo whenever you want so…
Image source: Thevilgenius_
#44
The double slit experiment. Light can behave like either particles or waves, depending on whether it is “observed” or not. When not observed light will show an interference pattern or act like a wave. But when observed it reverts to particle behaviour. Creepy science.
Image source: lofty2p
#45
There are more unique ways to shuffle a deck of cards ~10^67 than there are atoms in earth ~10^50.
Image source: big_redwood
#46
It’s wild how much of the universe is basically just hydrogen and helium. everything heavier is leftover star material and we’re part of that. that still doesn’t feel normal to think about.
Image source: BigBirdsBrain
#47
We are still in the stone age of our understanding of the human brain.
Metaphorically, have we learned to make fire, create interesting cave paintings, and invented the wheel? Yes!
But, are we missing a fundamental framework for even asking questions like ancient Greek, Arabic, or Chinese philosophers (much less theoretical or applied advancements like quantum mechanics or suspension bridges)? Unfortunately, yes.
We’re nowhere near as far along as most people think we are in neuroscience.
Image source: El-Dopa
#48
BMI is a joke that no doctor or insurance company should ever use. It only applies to average height younger white men.
If anyone ever tries to give you grief about it, ask them why they’re using a debunked standard of measurement rather than the much more accurate body composition.
Image source: BookLuvr7
#49
If you join an imaginary straight line connecting the two points of a crescent moon, it points south where the line meets the horizon.
Image source: garrawadreen
#50
I’m not a scientist, but I’ve always been fascinated with the fact that we can’t recreate materials and technologies like Roman Concrete (Marine Concrete) and True Damascus Steel. Our modern technology allows us to analyze ancient materials with extreme precision, but several historical materials cannot be exactly replicated due to lost “recipe” knowledge, unavailable raw materials, or specialized techniques that died with their creators.
For Roman Concrete (Marine Concrete), we have not fully replicated the long-term durability of Roman concrete, particularly its ability to strengthen over time when exposed to seawater. The secret lies in a specific, long-lost volcanic ash mixture that forms rare, reinforcing crystals (Al-tobermorite) that actually harden upon contact with salt water, rather than degrading like modern concrete. Our modern concrete pales in comparison.
And True Damascus Steel blows my mind. The original Damascus steel, made from “wootz” ore in India, was famously strong, flexible, and sharp, often featuring wavy, flowing patterns. The specific production technique and the raw materials were lost in the 17th or 18th centuries (??). Modern smiths cant recreate the exact nanotechnological internal carbon nanotubes composition structure.
Others like The Lycurgus Cup (Dichroic Glass) & Greek Fire are wild as well. Don’t get me wrong, as fascinating as these are, I’m almost glad they can’t be recreated by humanity now…I’m glad they were guarded secrets and “lost” to history. Modern-day humanity has a way of polluting things, a lot of times, and I’d hate to see those marvels warped into anything less than fascinating.
Image source: Nixthebitx
#51
Advances in electronics and battery technology now allow us to collar and track animals with transmitters. Many species move far greater distances than we imagined, and individuals seem know exactly where they are at a given point in time. For example, ducks return to the little pond in Manitoba to breed because it worked the year before, and when they head south they follow beeline routes of hundreds of miles to the exact wintering grounds that produced food last winter. And while on the way they alter routes to avoid places with lots of duck hunters.
Image source: Charr49
#52
The sheer scale of the sun is one of those things that just breaks your brain when you really look at the numbers. Like, the fact that we’re essentially just ‘decimal dust’ in terms of mass compared to the rest of the solar system is a wild perspective to have on a Tuesday afternoon.
Image source: mahirawrr
#53
Only about 5% of the stars in our galaxy could theoretically support life as we know it. The solar system is on a minor, isolated spur of the Milky Way called the Orion Arm, rather than one of its major spiral arms. Our location also falls within the galaxy’s “Goldilocks zone” far enough to be safe from the radiation and chaos of the galactic center, but close enough to have the heavy elements needed to build planets and support life, and with no big stars close enough to go supernova and wipe out the atmosphere.
Image source: A_C_Ellis
#54
The first hypothesis about climate change/the green house gas effect was purposed and tested starting in 1824. We didn’t do anything because action is difficult collectively just like it is now. We have a hundred years before the food chain collapse, maybe two.
I’d say its been a good ride but I’d be lying.
Image source: Legitimate_Read5970
#55
Quantum entanglement always freaks me out. Two particles instantly affecting each other across space? That’s basically magic from a physics perspective. The universe is weirder than we imagine.
Image source: Particular-Ratio-963
#56
One of the craziest facts in quantum physics comes from something called Bell’s Theorem. It basically shows that the universe cannot work the way we intuitively think it does.
Imagine you create two particles that are “linked” (this is called entanglement). Then you send them to opposite sides of the galaxy. When you measure one particle, you instantly know what result the other one will give. Not “really fast.” Not “almost instantly.” Instantly.
There are only two logical explanations:
The particles already had their answers decided in advance (like sealed envelopes).
They somehow communicate faster than light when you measure them.
Classical physics says the first must be true, because nothing can travel faster than light. But Bell proved mathematically that cannot work. And this has been experimentally confirmed over and over again.
So nature is forced into something deeply weird.
Either Information travels faster than light OR Particles don’t have definite properties until you measure them. And we’ve tested this in real labs. The universe consistently sides with the weird answer. Einstein called it spooky action at a distance. Now it’s pretty much accepted that the speed of light cannot be violated locally this has also been verified time and time again.
What this means is reality is not built on tiny solid objects with pre-set properties like we assumed. Like little Lego’s building up into a nice conformal structure. At a fundamental level, the universe does not behave like a classical machine. It’s not sci-fi, or speculative meta physics, it’s the reality we live in every day and based on experimentally verified physics.
EDIT:
The title of the thread is what’s something we know is true but people don’t know how crazy it is.
The many worlds interpretation, particles moving backwards in time and other stuff mentioned either have little or no verified experimental evidence.
Some interpretations of many worlds frankly border on meta physics.
Anyway I’m not judging how true these things are what I do know is there is evidence, strong evidence for Bells Theorem, therefore at this moment in time I can conclude it to be true, the other stuff could be true but I don’t ‘know’ it.
Image source: GovernmentInner1362
#57
Your entire life is almost two times less than one Neptunian year. If you’ve lived for a hundred years, Neptune would still have to travel 65 more years after your passing, to complete a single orbit. For people born in late 1930s, Uranus is just about to complete a single orbit. People born in the year 2000 can celebrate their first Saturnian year in 2029.
Image source: PrizeFront8677
#58
I am always intrigued by our vision continually getting worse despite better nutrition.
Image source: Old-Neat8900
#59
Light always takes the fastest path to its destination, even if its path is longer than a straight point between its source and its target.
i.e. light can and will take a non-direct path if that path would lead to the light getting it its destination faster, like by refracting through water or scattering in an atmosphere.
Image source: tayl0559
#60
The magnetic pole near the North Pole is actually a magnetic south pole.
Image source: Brunettae
#61
Mathematician here. You can easily memorize an 1031 digit prime number. Here, watch, I’ll start typing out the digits: 111111111111111111111111111111111111….
Yep, a 1031 ones is a prime number. And now you can tell people you have an 1031 digit prime memorized.
Image source: JoshuaZ1
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