65 Facts That Are So Fun That They Sound Unbelievable But They’re Absolutely True

Astronomers can watch the same event happen multiple times across years.

They’ve watched Supernova Refsdal, a single explosion, five times now. Four times in 2014, once in 2015. They also speculate they could have watched it explode sometime in the 1980s as well.

This is because light takes different paths as it travels around large celestial bodies, so arrives here at different times.

Might have misrepresented some stuff here, so if anyone more qualified would like to fact check me feel free.

The rainbow mantis shrimp is roughly a foot long , but it’s punch moves so fast that it heats the surrounding water to the same temperature as the surface of the sun.

You are being squeezed right now by the air pressure. We live at the bottom of an ocean of air at a comfortable 1atmoshere of pressure, which is 100,000 N/m2 which is 10,000kg per square meter.

You have approximately 2 square meters of skin, so are being squeezed by the air with a force equal to about 20 tons!!

2 identical cars colliding at 100kmh head to head is the same as 1 car colliding 100kmh into strong wall.

You would think 100 + 100 = 200, but not true because each car gets to complete stop in same time as if it would be when hitting the wall.

GPS satellites need two relativity corrections pulling in opposite directions, and without both, the whole system falls apart within a day. Their clocks run slightly slow because of their speed (special relativity), but slightly fast because they're sitting in weaker gravity up there (general relativity). The gravity effect wins out, netting about 38 microseconds a day of drift. That sounds tiny until you multiply it by the speed of light, at which point it turns into roughly 10 kilometers of position error per day if nobody corrects for it. The actual fix is almost anticlimactic, the satellite clocks are built to tick slightly slow before they're even launched, so once they're up there running fast relative to us, it cancels out to correct time.

Wet air is less dense than dry air at the same temperature and pressure.

Quantum mechanics, even explained, they require some effort.

The fact of the observable universe changes their behaviour because its being observed.

If you take all the planets in our solar system and line them up side by side, they can fit between earth and the moon when its at its farthest from earth. still find that hard to accept.. so much space.

Reducing speed limits actually decreases journey times.

PurahsHero:
For those of you not understanding this, journey times are significantly affected by congestion in most instances, especially stop-start traffic.

If you lower the speed, you decrease the gap between vehicles, thus allowing more people onto the highway in the same space, which helps to create free flowing conditions. That in turn speeds up your journey time overall.

Clearly if we made every road 10mph right now journey times would be longer. And we should do all we can to make public transport more attractive so we don't have this problem. But this is fundamentally how it works.

Source: Am a transport planner.

Light having no mass yet getting trapped in black holes sounds wrong. Gravity bends spacetime so paths curve in and nothing escapes.

That it would be harder to build a rocket to impact the Sun than it is leave the Solar System entirely.

I'm even reticent to post it because of the argument that can ensue: A plane can take off on a conveyor that's going just as fast in the opposite direction... just like normal. It doesn't propel itself using the ground/wheels like a car does. It's propeller though, hence the name, only cares about the speed of the air. The wheels will simply spin twice as fast because they're being dragged along. Imagine a car on solid ground towing a plane that's on a treadmill, that car is the propeller. I'm sure YouTube has the mythbusters clip somewhere... even the pilot of the plane they found to test it didn't think it'd work. Adam has said it's one of their most controversial myths and people still refuse to believe it.

Every organism emits an faint light.

Not super flashy but if you put a rope around the globe and wanted to make the rope 1m higher you would need just over 6 meters of rope.

Every human cell in your body contains about 6 feet (2m) of DNA.

Also human cells are in the minority of cells in your body. You're outnumbered by microbes by about 2:1.

More than 99% of a tree's solid mass is built from air and water.

A very small percentage, less than 1%, is trace nutrients from soil. All the cellulose structure and other parts of a tree are products of photosynthesis using CO2 from the air combined with water.

That's why there are no holes in the ground around trees, since they are extracting virtually nothing from the soil besides water. And the forest ground level raises year by year as trees fall and contribute their materials, extracted from the air, to the humus layer on the ground.

In semiconductors, the absence of an electron has more mass than the electron itself.

No one quite understands why elemental lithium has psychoactive properties, but the effects are are significant enough there are observable differences in crime and mental illness rates in populations with high amounts of lithium in their drinking water.

Time becomes slower for someone going faster.

As they approach to the speed of light it bocomes significantly slower. At 99% of C it becomes 7x slower and at 99.9% 22x slow. At 99.9999% of C it becomes 707 times slower.

So if you can go to a round trip of 1 year to and from Earth you will return 707 years later!

If you can go exactly at lightspeed C the time stops moving for you.

If you can go faster than light time will move backwards for you and you will go into the past.

It is a scientific fact that will sound like total nonsense.

The physiological reflex for hiccupping has been theorized to evolutionarily trace back to the body's respiratory response way back when we were still breathing with gills.