What scientific fact blows your mind the most?

The fact that there is no discernable difference between an alive body or a dead body when it comes to chemical makeup.
All the pieces are there. All the atoms and molecules are still in the same places. Yet despite this the body is still dead.

the implication of einsteins mass-energy equivalence formula is mind-blowing to me. one gram of mass, if perfectly converted to energy, makes 25 GWh. that means half the powerplants in my country could be replaced with this theoretical "mass converter" going through a gram of fuel an hour. that's under 10 kilograms of fuel a year.
a coal plant goes through tons of fuel a day.
energy researchers, get on it

The size of the universe and the distance between everything in it. It takes about 8 minutes for light from our own sun to reach us. And the observable universe is about 5,859,000,000,000,000,000 times larger than that! That is quite a trip. I would need about 293,283,000,000,000,000,000,000,000 charging stops with my electric car to get to the end. I think I’ll pass.
(Someone smarter than me will probably find out that my math is wrong)
- What I find mind blowing about the scale of the universe, is that on a logarithmic scale from the smallest possible thing to the largest possible thing, humans live at almost the exact centre.

There are more hydrogen atoms in a molecule of water than there are stars in the solar system
- 🤣 in Solar system only one star... the Sun! Go to school!!!
  
  so it's right
- Every 60 seconds in Africa, a minute passes
  
  Something should be done about this

The fact that planes are kept in the air by the shape of their wings, which forces air to go over at a pace when it can't push down on the wing as hard as it can push up from underneath. It's like discovering an exploitable glitch in a videogame and every time I fly I worry that the universe will get patched while I'm at 10,000 feet.
- I remember reading a couple years ago that's not actually how plane wings work. The actual way is much more complicated and hard to explain and hard to teach, so they just teach it this way because its an intuitive mental model that is "close enough" and "seems right", and it really doesn't matter unless you're a plane wing designer.
  
  The basic way an airplane works actually is simple and intuitive: it meets the air at an angle and deflects it downward. The equal and opposite reaction to accelerating that mass of air is an upward force on the wing.
  There is, of course a whole lot of finesse on top of that with differences in wing design having huge impacts on the performance and handling of aircraft due to various aerodynamic phenomena which are anything but simple or intuitive. A thin, flat wing will fly though, and balsa wood toy airplanes usually use exactly that.
  https://en.wikipedia.org/wiki/Lift_(force)#Simplified_physical_explanations_of_lift_on_an_airfoil
- Tbf, you can make anything fly if you give it enough thrust. Wings just make it easier.
  
  In a sense, everything can fly. Just sometimes not for very long.
  
  https://i.imgur.com/lDSBuud.gif

A Planck length is the smallest length possible, a smaller length simply can't exist.
At least that's what scientists believed until they studied OPs penis, then they found out something smaller does in fact exist.
- Dude! I told you in confidence not to share that info.
  I guess I have no choice but to share that @spittingimage@lemmy.world has the world's biggest human anus. It's been a scientific mystery about how it got to be so big.
  
  I said out loud at a Warhammer convention that space marines are just dolls for grown men.

You can observe the chirality of some molecules from the crystals they form, sometimes they twist clockwise, other times they twist counter clockwise. Which way they twist is dependent on their molecular structure.

For me, it's the sheer scale of celestial bodies.
Our Sun is humongous. UY Scuti's radius is 1700 times larger - 185300 times larger than the Earth. And then there's TON 618, which has a mass 66 billion times larger than our Sun's.
And even those are barely grains of sand when compared to solar and galactic structures... It is humbling, to say the least.
Edit 2: I deleted the previous edit, because my first observation is correct (scale is maintained when going from comparing radii to comparing diameters...), which is why I have an Arts degree.

If math is actually uncovering fundamental laws of the universe, rather than just describing it at various scales, then there's a chance we can rewrite reality with our own set of rules that would render the current ones incompatible (by Gödel's-IT).
https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis
- Tegmark's MUH is the hypothesis that our external physical reality is a mathematical structure.[3] That is, the physical universe is not merely described by mathematics, but is mathematics — specifically, a mathematical structure.
  Look, I only heard about this concept, so maybe there's more to it, but branches of mathematics are just a set of rules that we create.
  Sometimes these rules can be applied to real systems, in our reality, and that helps to describe and understand the universe.
  But it's totally possible to come up with infinite nonsensical, useless mathematical systems that have nothing to do with the universe. The existence of these doesn't mean that we have or could rewrite reality.
  
  If our universe is bound by the laws of mathematics (big IF), then any theorem discovered within it has to be consistent or incomplete w.r.t it.
  If a theorem is discovered that upends math as we know it, then the repercussions could be cosmic.
  Again, big if about the universe being bound by the laws of maths

There are more stars in the visible universe than there are grains of sand on all the beaches in the world.

95% of our DNA is basically useless gibberish. Since the evolutionary incentive to shorten it is so small in our case, all sorts of processes "hijack" it to propagate themselves without giving anything back.

In chemistry I was taught one carbon atom can exist in at least 12 separate living bodies before it's no longer stable.
- As you established that is not true, however you can add some of that carbon from some body and add it to the iron from the blood of 400 other human bodies so you can forge one nice sword.
- Hon I think you maybe misunderstood your chem class.
  Carbon is carbon is carbon and doesn't know or care if it's in a living body.
  Carbon-14 has a half life of 5700 years. This means that through random decay, the approximate rate of decay is one half of a given amount every 5700 years, this of course breaks down when you reach the single-digit quantities of atoms.
  Now, this has nothing to do with the stability of an atom of regular-ass carbon-12, your common garden variety carbon, which is extremely stable and would require outside influence to decay into another isotope.
  
  Ahhh I misremembered. It was this "The average carbon atom in our bodies has been used by twenty other organisms before we get to it and will be used by other organisms after we die."
  It's been six years since that class.
- that doesn't make any sense. Carbon doesn't get less stable by being used in bodies.
  Carbon 14 exists, but that decays regardless if it's in a body or not. At has quite a long half life
  
  Yea, I misremembered it. It was in my book from a while back. Here we go:
  
  At least is a heavy lifting qualifier in this case.
- What does that mean?
  
  After you die, the carbon atoms that made you might go on to make another living thing.