"The farthest galaxy we can detect was 13.4 billion light years away when it emitted the light we see today. That light (not the galaxy, the light itself) is three times as old as the Earth."

"Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying."

"There is a theory (Proton decay) that states that protons, one of the fundamental building blocks of matter, can just spontaneously evaporate. The amount of time this takes is astronomical, but current theories predict that all matter in the universe will decay away until there is nothing left but particles of light and empty space. The time it will take for this to happen is incomprehensible, but it is the most likely scenario for how our universe will "end."

"The fact that the Voyager 2 Space probe after over 40 years has not even hit a pebble....."

"If you gathered together all the matter in the universe we can observe right now ,and squished it together until it had the density of water, (1gm/cm^3) it would fit into a cube about 1 light year on each side. There are several disturbing things about this. A single light year is almost unimaginably huge. A cubic light year is a ridiculous volume of space. The observable universe is 33 orders of magnitude larger than that. It is almost entirely empty."

"The largest black hole we have discovered has a diameter of 490.000.000.000 km. Earth's diameter is roughly 13.000 km."

"There is no up or down."

"Time-lapses of the Future send me into an existential crisis every time."

"Here’s one closer to home. The Kessler Effect is the theory that a single destructive event in low Earth orbit could create a cascade where satellites break up into tiny fragments taking out other satellites, breaking up into smaller fragments and so on, until the earth is completely surrounded by a massive cloud of tiny flying death shrapnel, which would make leaving this planet almost impossible. If you look up how much space debris there is already up there and how many satellites currently orbit, plus the continued growth of the commercial space industry... I think about it a lot."

"Somewhere, something incredible is waiting to be known."

"That we, as a planet, are literally flying through Space. I dont just mean around the Sun, because our Solar System is flying through space as well. Along with our Galaxy too. Where Earth was one minute ago is a point in space that we will never return too."

"Rogue planets. Such objects have been ejected from the planetary system in which they were formed or have never been gravitationally bound to any star or brown dwarf. If a rogue planet invaded our Solar System, things could go very wrong."

"In about 150 billion years, intergalactic transportation and communication beyond our local supercluster will be impossible. In about two trillion years, galaxies outside of our local supercluster are no longer detectable due to redshift. Assuming the universe keeps expanding, then the universe’s final fate depends on whether or not protons decay."

"More of a theory than a fact, but I find the Dark Forest theory pretty disturbing. Basically the idea that there are other civilizations out there but they are staying quiet for good reason."

"I truly don’t believe most of us are capable of comprehending the vastness of space and the distance between things."

"There are voids in the universe that are so big that if you were teleported to the center with a spacesuit on, you would just see pitch darkness in all directions."

"In 2019, scientists at the Royal Institution of Australia (along with NASA and other international space agencies) completely missed a football-field-sized asteroid that came eerily close to Earth's atmosphere and had apparently realized it only minutes before it passed Earth."

"The near impossibility of interstellar human travel."

"We still don't know exactly how it came into existence."

"At 600KM above planet Earth the temperature fluctuates between +258 and -148 degrees Fahrenheit. There is nothing to carry sound. No air pressure. No oxygen. Life in space is impossible."

"I just learned about something called 'Angular Diameter Turnaround.' Basically, "things that are far away look smaller; but things that are really far away look bigger, because when their light was emitted, the universe was small and they were close to us."

"How easy it would be to become completely and totally isolated out there. In space, technology is the only thing keeping us alive. The only reason we don't freeze suffocate or starve. Imagine the day when humans advance to traveling deeper into space. Imagine not having communication. Completely alone in the blackness of space. Or even worse, your engines die and you're just forced to sit, hoping and praying that somewhere in the vast universe someone comes across you. That's scarier than any movie monster."

"The images you see are galaxies not as they are but as they were, based on how many light-years away they are. This is fine for anything within the thousands but if we are talking millions or billions of light-years away then there is a good chance that none of those stars you see even technically exist right now. On the bright side though, if we can figure out how to move faster than light then we could see our own planet with a good enough telescope as it was in the past. We could observe any outside historical event or even dinosaurs."

"We could literally get vaporized at any moment from a space death laser traveling at the speed of light, so we can't even detect it before we're dead."

"Time is not linear due to the constant expansion of space therefore time is expansive."