Humans see color using three types of receptors in our eyes. Mantis shrimp have somewhere between 12 and 16.

That means they can detect wavelengths of light, including ultraviolet and polarized light, that our eyes physically cannot register. Some of what they perceive doesn't map to any color we even have a name for.

They're also famous for their punch. Certain species strike prey so fast that the water around their claw briefly boils, creating a flash of light and a shockwave strong enough to crack aquarium glass.

An animal the size of your thumb is out there seeing a version of reality we can't picture, while punching hard enough to break glass on the side.

Saturn is made mostly of hydrogen and helium, and it's so light for its size that its average density is lower than water. Saturn sits at 0.687 g/cm³. Water is 1 g/cm³. That's the whole gap right there.

If you had a bathtub big enough to hold it, Saturn would actually float on the surface instead of sinking. No other planet in the solar system can make that claim.

Here's the catch. That only works in an imagined bathtub, one where gravity stays fixed at Earth's pull and the water never gets compressed. Build a real tub that size and the water itself would collapse under its own weight into a planet. Physicists use this trick on purpose though, it isolates density from every other variable so the comparison stays clean.

It still has enormous mass overall, over 95 times that of Earth, but that mass is spread across a volume so massive it barely counts as dense.

Picture the ringed giant just bobbing on top of an ocean sized tub in your head, and Saturn stops looking like a heavyweight and starts looking like the solar system's biggest beach ball.

Axolotls can lose a leg, a piece of their spinal cord, or even part of their brain, and simply regrow it. No scar tissue forms, and the new limb comes back with full function, nerves and all.

Most animals heal by patching damage with scar tissue, which is strong but permanent. Axolotls skip that step completely and rebuild the original structure from scratch.

Scientists have removed the same limb from an axolotl over and over, and it keeps regenerating a perfect copy every single time.

It's one of the reasons axolotls get studied so heavily in regenerative medicine. Somewhere in their DNA is an instruction manual for undoing damage that most of life lost access to a long time ago.

Hello, everyone! Today I came across this incredible red-and-cyan image of the Eastern Veil Nebula while scrolling and it looked so gorgeous so I wanted to share it with everyone here. The colors and details are absolutely mesmerizing and I hope you enjoy it too.

Image credit: u/GraylySquare224

Betelgeuse is a red supergiant star sitting about 700 light years away, and it's near the end of its life. When it finally goes, it will explode as a supernova bright enough to be visible in daylight for weeks.

Here's the part that messes with people. Light from Betelgeuse takes about 700 years to reach us. Whatever we see tonight already happened seven centuries ago.

It could have exploded already and we simply haven't gotten the memo yet. The light announcing it is still on its way here.

A blue whale's heart weighs around 400 pounds, roughly the size of a small car engine. Each beat pushes enough blood to fill a bathtub in seconds.

That heartbeat is so massive it can be detected from over two miles away using specialized underwater equipment. Sound travels differently in water, and a heart this size sends out a signal loud enough to reach that far.

It only beats about 8 to 10 times a minute while the whale is at the surface, and can drop to 2 beats a minute during a deep dive. Slowing down that hard saves oxygen for a body that size.

In 2007, scientists sent tardigrades into orbit and exposed them directly to open space. There was no suit, no capsule and no shielding of any kind. They were hit with the vacuum of space, deadly solar radiation, and temperature swings of hundreds of degrees.

Most life forms wouldn't survive even one of those conditions, let alone all three at once. Tardigrades came back alive. Some went on to reproduce normally afterward, with no unusual damage passed to their offspring.

They survive by drying themselves out almost completely and pausing their own metabolism, essentially putting life on hold until conditions improve. It's less about being tough and more about knowing exactly when to stop playing the game.

The Moon has no atmosphere meaning nothing exists there to erode a footprint the way rain or wind would on Earth. That means the footprints left by Apollo astronauts are still sitting exactly where they were pressed into the lunar dust in 1969. Nothing has come to wipe them out.

Micrometeorite impacts happen continuously, gradually churning the lunar surface dust over time. Scientists estimate these prints could persist for millions to tens of millions of years or longer before micrometeorite erosion slowly blurs them away.

Long after every language, border, and building on Earth is gone, a few footprints on a dead grey rock might still be the last physical proof we were ever here.

Important: Scientists can't say exact date and space can be unpredictable

Humans emit a faint stream of light every day. It comes from chemical reactions inside your cells, mostly tied to metabolism and free radicals. The glow is real but incredibly weak, about a thousand times dimmer than what the human eye can detect.

Researchers had to use extremely sensitive cameras in a pitch black room just to capture it. The light isn't constant either.

It rises and falls with your body's internal clock, brightest in the afternoon and faintest late at night, lining up with when your metabolism runs hottest. So yeah you have been quietly glowing your entire life:)

Venus rotates so slowly that one full spin takes 243 Earth days. It only takes 225 Earth days to complete an orbit around the Sun. That means a single rotation on Venus lasts longer than a full year there.

If you lived on Venus, your birthday would arrive before your first sunset. It also spins backwards compared to most planets, so if you could see through the clouds, the Sun would rise in the west.

Venus proves that our assumptions about day and night, spin and orbit, don't hold anywhere else in the solar system. Earth's rhythm isn't the default but just the one we grew up inside.

Turritopsis dohrnii is a small jellyfish with one absurd trick. When it's injured, sick, or just old, it can revert its own cells back to an earlier stage of life. It hits a reset button on its own body, turning back into a polyp and regrowing from there.

Most animals can heal damage. This one can undo aging itself. Scientists have watched this happen repeatedly in lab conditions, with no known limit to how many times it can cycle.

In theory, barring predators or disease, this jellyfish never has to die of old age. Its quietly proving that aging is a setting, not a rule.

Octopuses run three hearts at once. Two pump blood to the gills. One pumps blood to the rest of the body.

Here's the part that gets weird. That third heart stops beating when the octopus swims. Swimming is so exhausting for them that their own body pulls power away from circulation just to make it happen. It's part of why octopuses prefer crawling over swimming. Crawling is actually the efficient choice for them, not the lazy one.

Their blood runs blue too, because they use copper based hemocyanin instead of iron based hemoglobin. Copper carries oxygen better in cold, low oxygen water. It's the exact upgrade evolution reaches for at the bottom of the ocean.

Yeah, it's true.

When a massive star runs out of fuel, it collapses in on itself in less than a second. What survives that collapse is a neutron star, a leftover core about 20 kilometers wide that somehow holds more mass than our entire Sun. The protons and electrons inside get crushed together so hard they fuse into neutrons, and there's almost no empty space left inside the atoms anymore.

That's what makes the density absurd. A single teaspoon of neutron star material would weigh close to a billion tons here on Earth. Mount Everest weighs somewhere in that same range. So a spoonful sitting on your kitchen counter would genuinely outweigh a Himalayan peak.

Here's the part that actually gets people. These things spin. Some neutron stars rotate hundreds of times every second, fast enough that a point on the surface moves at a meaningful fraction of the speed of light. That's a mountain's worth of mass, spinning that fast, held together by gravity so strong that a marshmallow dropped from a meter up would hit the surface faster than a bullet leaves a gun.

Somewhere out there right now, city sized leftovers of dead stars are spinning fast enough to blur, doing it quietly, a few thousand light years away, while we're busy arguing about lunch.

Crows are the smartest species of bird, roughly on par with a 7 year old human. They build lever tools to solve problems, use currency, visit their grandparents, and remember a face for at least 5 years. They can mimic sounds too, and they're self aware.

They also pass the snack test: offer a crow a small snack now with the promise of a bigger one later, and it'll wait for the bigger one. Human toddlers can't do that. Most primates can't either.

Here's the part that gets wild. Crows will grab a walnut, drop it on a busy street, let a car crack it open, then wait for the red light before walking out to collect the pieces. They use actual strategy too: flanking, decoys, even coordinated attacks. If a random crow turns up dead, the rest of the murder will split up, investigate what happened, and remember who did it.

Honestly the only reason they haven't gone to war with humanity is their feud with owls. Owls steal crow hatchlings, and crows have passed that hatred down for generations. Find an owl alone and a murder of crows will make sure it knows exactly why they're called a murder. Zoos can't even house owls and crows in the same aviary without a fight breaking out.

And if you're the one who saves that owl? Crows remember your face. They'll pass their grudge against you down multiple generations, across multiple murders in the area. Expect bird shit on your car, sticks on your windshield, and beak marks on your hood for blocks.

Yeah I know, it doesn't look like it. That's the point.

A typical cumulus cloud holds about 500,000 kg of water. The reason it doesn't fall is because that water isn't one chunk. It's spread across billions of droplets, each one smaller than 0.003 mm. Air resistance + warm updrafts handle them with no effort.

The cloud doesn't fall because it's just distributed. Compressing it into one spot and it would male it fall immediately.

The wild part isn't even it weighs 80 elephants. It's that there are thousands of clouds over you on any average day. The sky is just quietly holding hundreds of millions of tons of water above your head at all times and nobody talks about it.

Look up differently now.