r/FactUp

So I went down a rabbit hole today trying to understand why nothing can travel faster than light and honestly my brain is still recovering.

Here is what blew my mind the most:

It is not just a rule someone made up. The universe literally prevents it. As any object speeds up its mass starts increasing. The faster you go the heavier you get. By the time you get close to light speed you would need infinite energy just to push yourself a tiny bit faster. And infinite energy simply does not exist anywhere in the universe.

But here is the part that completely broke me.

If you somehow actually reached light speed — time would stop. Not slow down. Not pause. Completely stop. From your perspective the entire universe would freeze. Every star every galaxy every moment suspended in absolute stillness while you move through it all.

And we do this every single time we switch on a torch. Those tiny photons shooting out are already moving at the maximum speed the universe allows. A humble flashlight firing particles at the ultimate cosmic speed limit.

300,000 km per second. Seven times around the entire Earth in one second. The undefeated champion of the universe.

Physics is genuinely the most insane thing ever.

Too expensive?? Too posh to understand?‼️

A machine made to make cows happy

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Snow leopards ambush prey from above, taking animals three times their weight. They wrap their tails around their faces against mountain cold and unlike other big cats they cannot roar, instead making a haunting chuff across Central Asia’s harshest peaks.

The kookaburra’s famous laughing call is actually a territorial warning, echoing through Australian bush at dawn and dusk to mark boundaries. A member of the kingfisher family, it hunts snakes and lizards by slamming them against branches to kill them before swallowing whole.

Fruit bats span nearly 2 meters wingspan yet are gentle pollinators dispersing seeds across vast tropical distances. Without them entire ecosystems would collapse, making these often feared creatures among nature’s most important and underappreciated gardeners.

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Wasps control insect populations and pollinate plants, making them far more valuable than their reputation suggests. Unlike bees they can sting repeatedly, but most species are solitary and non-aggressive, with only a handful living in the colonies people actually fear.

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The Ezo Momonga is an adorable flying squirrel species unique to Hokkianda, a large island in northern Japan

The LaserWeeder gets rid of weeds without using chemicals.

Tokyo’s G-Cans system is one of the world’s largest flood tunnels, connecting five massive silos via a 6.4km underground channel that can drain 200 tonnes of water per second during typhoons. Built after catastrophic flooding, it has reduced flooded areas by roughly 80% since opening in 2006.

Nothing in the universe can outrun light — and the reason why will break your brain

Treehoppers wear elaborate helmet-like growths mimicking thorns or fungi, and communicate through plant-stem vibrations inaudible to humans. Some species are tended by ants in exchange for secreting honeydew, making them tiny farmers of the insect world.

Butterflies taste through their feet, allowing them to detect food the moment they land. They survive on liquid alone, drinking nectar through a coiled tongue, and despite appearing fragile, some migrate over 4,000 kilometers, navigating by the sun using an internal biological clock.