Cosmic Oddities: Space Facts That Sound Impossible But Are True

From a photon's "point of view" time and distance are zero.
(Photons cannot really have a POV since they don't have a rest frame.)
So a photon emitted by a star a billion years ago would be absorbed by your eye with no time passing in between.

Black holes are the universe’s existential panic attacks, screaming so loudly that even light gets scared and freezes. They are cosmic vacuum cleaners with no off switch, running on a diet of pure time and regret. If you fell into one, you would be stretched into a single noodle of spaghetti, proving that the laws of physics ultimately prefer Italian cuisine over human geometry.

Every single electron in the universe is perfectly identical. They don't have variations in size, mass, or electric charge.

The universe is expanding faster than the speed of light, which seems impossible but is backed by evidence.

The energetic phase of the universe’s existence will be much, much shorter than the amount of time that will pass when all particles in existence are so distant from one another that interaction between them is impossible.

All the billions of stars, galaxies and everything in them are literally just very fleeting sparks in an almost unimaginably vast expanse of time.

Not an astronomer, just a space nerd who falls down Wikipedia holes at 2am. The one that broke my brain: the observable universe is about 93 billion light-years across, but the universe is only 13.8 billion years old.

How? Nothing traveled faster than light. Space itself expanded between us while the light was traveling. So the light took 13.8 billion years to reach us, but the stuff that emitted it is now like 46 billion light-years away in every direction.

It’s like walking 10 miles on a moving walkway and ending up 20 miles from where you started. I still don’t fully accept it emotionally.

We can tell how long ago the solar system formed by looking at ratios of radioactive isotopes in little glassy blobs called chondrules found inside meteorites.

Time dilation and length contraction are like two sides of the same coin. 

Observer sees the rocket on its way to Andromeda blasting past at 99 percent C and observes their time moving so slow its almost stopped.

Crew on the rocket time moves normally but due to length contraction arrive almost instantly. The rocket
 turns around and returns  to Earth again almost instantly, but the observer who saw them depart is
millions of years d**d.

Orbital speed fact:

Orbit basically means 'travel sideways so fast that even though you are always falling, the horizon falls as fast as you do.'

The International Space Station (or any other body in stable low earth orbit) travels so fast that in the time it takes a rifle bullet to cross a cricket pitch (~20 metres from one wicket to the other), the ISS would have crossed the entire stadium, grandstand, oval and all.

Amost everything we know about objects we can never visit comes from tiny signals: photon.

A photon can leave a distant galaxy billions of years ago, cross an almost unimaginable expanse of space, and eventually hit a detector on Earth. From that tiny piece of information - thanks to the efforts of researchers - we are able to infer the galaxy's composition, motion, temperature, age, and sometimes even the presence of objects we cannot see.

We essentially reconstruct the universe from clues that have travelled across it to find us. I work with this data everyday yet it never fails to awe me.

A meteor shower is most often the result of earth passing through the tail debris of a comet.

When we observe a photon from the CMB we are observing a photon produced in the youth of the Universe, billions of years ago. However, from the reference frame of this photon, it was just created and literally no time has passed for it.

There is no scientific proof of passage of time. Time exists as a coordinate, but there isn't a single formula or experiment that can prove that time actually flows. It's just how we perceive it.

Mass does not create gravity by bending space-time.

The space-time actually IS bent and we call the result mass and gravity.

Also there ist no matter in the universe. It is all just energy interacting on different levels. "Solid" ist just our description for the strong forces coupling the dots of energy (quarks, electrons).

So basically the universe ist just bent space-time, creating "mass" on one side of the medal and "energy" on the other. There is even a formular describing the connection. ;-).

We have no clue what ~95% of the observable universe is made out of.

There is no true "now" in time. Now has no universal meaning. It makes no sense to even ask what is happening "now" in the Andromeda galaxy.

That even the known universe is much much bigger than the Big Bang Theory suggests it should be per the math. It is roughly 95-100 billion light years from side to side & it should be, in "reality", about two thirds that size. There are so many awesome things like this btw, unexplainable to our ken.

People often underestimate distances in astronomy. The moon is so far from the Earth, you could put all the planets of our solar system between.

Also the evening star is actually Venus.

We're closer to the size of the observable universe than to the Planck length.

Here's something fun.

The Speed of the Universe and space itself expanding, is faster than the *speed of light itself* at this point.

If you want an explanation for this just ask, I can explain this one.