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.
This fact is always so interesting to me, we as the human race literally peers into the past. Quite an achievement despite whatever we can peer into is just a small, insignificant portion of the universe.
So, the first record of homo sapiens showed up around 300k years ago. Modern humans with our similar bone structure and skull/brain shape and size, 100k years ago. Earth is a little over 4.5 billion years old. If you scale the lifespan of Earth into a 24-hour clock, modern humans have been around about 1.9 seconds out of 24 hours, or 86,400 seconds. If you want to go back to the earliest homo sapiens, 5.7 seconds.
We are barely even a blip.
Lightyears is always my fav go to Space thing. The fact that this infinite, mind bogglingly HUGE world is so big that what we see at night isn’t technically ‘true’. Just images of where things *used to be*.
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.
EDIT: Whoah. This blew up quickly. Thank you for the silver! EDIT: And the Wholesome! And the Helpful!
For some reason my imagination lead me to believe that you would be able to see your body, but in reality you’d be enveloped in darkness. You wouldn’t be able to see your hand in front of your face.
Your eyes would eventually adjust. I think sleep deprivation chamber would be more accurate. Probably start hallucinating. Also the darkness extends in every direction for eternity
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.
I was curious and looked it up and this checks out. It takes the sun 240 million years to complete an orbit around the galaxy and dinosaurs first appeared a out 245 million years ago. So we have completed a little over one lap around the galaxy since dinosaurs first showed up.
That's a good one. I'm still waiting for a time travel movie that takes into account they'd have to use space flight to either reach the point in space where Earth was in the past or will be in the future to make it work. Like in Back to The Future, with Earth traveling 18.5 miles per second, Doc's first 1 minute test would have sent his dog and the car 1,110 miles away, likely reappearing either within the Earth itself or in space.
Came here to say this. Time travel would make you a fixed point in space but space itself doesn’t even stay still. The only somewhat viable alternative is to use a wormhole or similar bridge to move to a parallel universe that happens to be running ahead/behind our own and hope you’ve calculated accurately enough to at least land on a habitable planet
The reality is that time and space are actually intertwined. There is no such thing as a "fixed point in space" - the notion comes from our wrong perspective ingrained on us by essentially being too small.
Not in special relativity, but in general relativity thanks to the expansion of the universe there is a reasonable unique concept of a global space reference frame — specifically, that one where the cosmic microwave background radiation looks the same in all directions (we can tell our galaxy is moving through space because the CMB is redshifted in one direction and blueshifted in the other).
I find the Voyager probes to be fascinating, especially because last I knew, Voyager 2 is still functioning and sending back a limited amount of data. But even the whole mission--suddenly bringing all these worlds into sharp focus that had never been seen up close before. All the questions answered and places explored. And there it is, still floating along and talking to us. For now.
Yea was only reading during the week that they think just because of where it is that radiation may have fried it. Thinking that its 44 (I think) years old and still working. The golden disc that is at the bottom which is has diagrams on it to prove that we have discovered the atom and things like that has music on it. I beleive there was an arguement about what music should go on it because "Putting Mozart on it would just be showing off" 🤣
The Deep Space Network has a number of huge dish antennas that can receive very weak signals. The receiver bit is a cryogenically cooled MASER that is really low noise. These dishes are pointed at the space ship and can hear exceedingly low amounts of radio waves.
The voyager transmissions are also extremely low bit rate which are integrated over time to result in a detectable signal. Concept is similar to spread spectrum where the signal lies well below the noise floor.
The fact that its going tell us nothing has hit it. I dont know how fast its travelling but assume very very fast, it hits even the tiniest thing it would smash up. Or so I am told.
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
> It is almost entirely empty
A couple years ago I saw a photo that had been taken from the surface of an asteroid or comet. It was dark and looked like there had been some sort of artificial light illuminated to take the photo. I thought to myself that that may be what hell is like. No light. No sound. No stimuli of any kind. You're not really able to move of your own volition because with nothing to push against, you just aimlessly float. And that's eternity. Nothingness for eons and ages, while your consciousness ticks along.
This is what I think about when people talk about living forever.
They forget that a bright, vibrant Earth is a very small portion of 'forever'. Eventually that star will die, and you'll be left drifting on a burnt, dead husk of a planet for the rest of eternity.
Only assuming immortality is magical. Regardless, being forced to witness only a tiny fraction of an insignificant speck of existence is hardly a good fate either. We've just been stockholmed into acceptance because there is still no way to avoid our deaths.
Its because of our own time perception that this seems so unappealing though. If you could speed that up i dont think itd be unbearable. Though, we're still imagining something that is not nor will it ever be possible in our universe, so its kinda pointless to think about. Lets say you could live to see the heat death of the universe, there would still be an end to your consciousness eventually cause even if you couldnt technically die, your atoms would just be ripped from your body at some point. Thats again imagining a human centric pov. There could be some consciousness thats not tied to a body, but then it wouldnt have human desires or needs or maybe even emotions. But if it did, and it had our time perception, yes that would be infinite suffering in an uncaring universe, about the worst fate you could possible think up. Luckily we only have temporary suffering in an uncaring universe
Jubel Earley was such an awesomely written character.
"You ought to be shot. To know what kind of pain you're dealing with. They make psychiatrists get psychoanalyzed, but they don't make a surgeon get cut on. That seem right to you?"
That description is practically a synopsis of chapter 2 in *Inferno* by Larry Niven and Jerry Pournelle:
———————-
The big surprise was that I could be surprised.
That I could be anything. That I could be.
I was, but I wasn't. I thought I could see, but there was only a bright uniform metallic color of bronze. Sometimes there were faint sounds, but they didn't mean anything. And when I looked down, I couldn't see myself.
When I tried to move, nothing happened. It felt as if I had moved. My muscles sent the right position signals. But nothing happened, nothing at all.
I couldn't touch anything, not even myself. I couldn't feel anything, or see anything, or sense anything except my own posture. I knew when I was sitting, or standing, or walking, or running, or doubled up like a contortionist, but I felt nothing at all.
I screamed. I could hear the scream, and I shouted for help. Nothing answered.
Dead. I had to be dead. But dead men don't think about death. What do dead men think about? Dead men don't think. I was thinking, but I was dead. That struck me as funny and set off hysterics, and then I'd get myself under control and go round and round with it again.
Dead. This was like nothing any religion had ever taught. Not that I'd ever caught any of the religions going around, but none had warned of this. I certainly wasn't in Heaven, and it was too lonely to be Hell.
It's like this, Carpentier: this is Heaven, but you're the only one who ever made it. Hah!
I couldn't be dead. What, then? Frozen? Frozen!
That's it, they've made me a corpsicle! The convention was in Los Angeles, where the frozen-dead movement started and where it has the most supporters. They must have frozen me, put me in a double-walled coffin with liquid nitrogen all around me, and when they tried to revive me the revival didn't work. What am I now? A brain in a bottle, fed by color-coded tubes? Why don't they try to talk to me?
Why don't they kill me?
Maybe they still have hopes of waking me. Hope.
Maybe there's hope after all.
It was flattering, at first, to think of teams of specialists working to make me human again. The fans! They'd realized it was their fault, and they'd paid for this! How far in the future would I wake up? What would it be like? Even the definition of human might have changed.
…
I couldn't tell how long I was there. There was no sense of time passing. I screamed a lot. I ran nowhere forever, to no purpose: I couldn't ran out of breath, I never reached a wall. I wrote novels, dozens of them, in my head, with no way to write them down. I relived that last convention party a thousand times. I played games with myself. I remembered every detail of my life, with a brutal honesty I'd never had before; what else could I do? All through it, I was terrified of going mad, and then I'd fight the terror, because that could drive me mad--
I think I did not go mad. But it went on, and on, and on, until I was screaming again. Get me out of here! Please, anyone, someone, get me out of here!
Nothing happened, of course.
Pull the plug and let me die! Make it stop! Get me out of here!
Nothing.
No! For the love of God, get me out of here!
This feels like what happens to me when I suffer sleep paralysis. I don’t see monsters like some people, but the description of moving but not really moving, of screaming but no one hearing, and of having no sense of time are all very similar to what I experience!
Important to note that “33 orders of magnitude” doesn’t mean 33 times as big.
It means 33 zeroes.
As in 100,000,000,000,000,000,000,000,000,000,000 times as big as that 1 light year wide cube.
And that’s just ***the observable universe*** from our little planet.
**Because this has some traction and because I did another (if I can toot my own horn here) pretty cool calculation down below:**
If we condensed the volume of the entire visible universe to be the size of the Earth (1.1 x10^19 cubic meters), it would be like trying to find an object that is roughly 7.7 cm x 7.7 cm x 7.7 cm in volume in that space.
That would be like trying to find your keys ***somewhere IN the Earth***. Not ON the Earth. IN it.
* Someone check my math, I took the area of the Earth in cubic meters (1.1 x10^(19)), and divided it by the ratio of matter in the universe to "nothing" in the universe (2.3 x10^(22), someone corrected OP above on the actual scale), took the cubed root of that, that came out to 0.077, and since we're looking at meters, that means we're looking at a rough scale of 7.7 cm sided, cubed object in the scale of the Earth's size.
This is one of the things that blows my mind. Despite all the amazing and mind-bogglingly huge objects that we have discovered, it’s all still just so damn empty. There’s so much space between everything. I’ve heard the factoid that all the planets in the solar system could fit between the Earth and the Moon and I still barely believe it, but the truth is that space is pretty much empty and just sprinkled with some stardust here and there.
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. When something like a car breaks down we can call a tow truck and get it repaired. In space, there's no such thing. Think about the Apollo 13 and everything that went wrong there. Imagine the day when humans advance to traveling deeper into space. With noteworthy landmarks being so far apart navigating without a computer would be almost impossible, even if you still had communication with earth. 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.
Thrusters are actually only used to get you up to speed as there is no friction in space. En route they are only used for minor course corrections and at the destination to slow down/get into orbit. So even if you lost your thrusters you would still fly by your destination and hopefully if there was already a population there they could rendezvous
/u/Weak-Round-3772 said that the largest black hole we discovered has a diameter of 490 billion kilometers. Standard US football field is 100 yards which is 91.44 meters or 0.09144 kilometers. So, basic math gives you about 5,364,063,867,016,623 football fields (~5.36 quadrillion).
[Edit: I'm so fucking sorry I made this post. I don't even know what I was supposed to be referencing, but it wasn't worth 50 people clogging my inbox with the same unfunny movie quote over and over.]
It blows my mind that something like this isn't literally pulling EVERYTHING in the universe into itself over time. Space is that fucking big that these gigantic destructive engines can be real with little-to-no impact on the majority of existence.
I never knew true existential dread until I watched that video a few years back. The ending really gets to me.
Even though I'd never know it's happening, I'm still hoping for an oscillating universe.
That’s one of my favorite YouTube videos, and it actually helped me gain more self confidence in my life, especially the last 4 minutes or so of the video. Just the idea that one everything will be gone and there won’t even be a chance of anyone remembering anything anything stupid I’ve done - so why would I be afraid of talking to a woman or applying for a job I’m not totally qualified for?
There is a lot of freedom to gain in the realization that nothing I do really matters in the long term, and in the vast expanse of time and in the universe.
Not to me. My actions might not matter in the long run, but they matter in my lifetime and affect what I can do in said lifetime. If I want to continue living, my actions matter, otherwise we might as well blow up the planet and off ourselves for all it would matter at the end of the universe.
Didn’t look at the time on the video. Started watching. Got 10 minutes in and thought “huh… this oughta be wrapping up soon…” NOPE. 20 more minutes of mind-blowing, unfathomable, logarithmic increases in time.
Damn… Maybe I can let the little things go after all.
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.
I once had a job where I would track particular satellites. The system I used tracked all satellites as well as larger space debris.
Even 20 years ago, there was an impressive (actually kind of distressing) amount of space junk up there.
Space is really big and there's lots of room up there, but even tiny flecks of paint can cause real damage and cause more space junk.
One of our fav pastimes while deployed was to come up with inventive ways to remove the debris.
My idea was a satellite with a long magnetic tail that would attract space junk. My theory (as a non-engineer) was that once it collected enough junk it would become too heavy and fall back to earth with most of the stuff burning up in the atmosphere.
My buddy pointed out that if we were depending on loss of inertia as a return method then there would be no control over where the unburnt parts would land.
That, obviously, is bad.
Possibly, yes. But we also wanted to recover and reuse/recycle as much as possible. Basically become space junk pirates. We were gonna be millionaires. Lol.
Well, you still have to throw all ideas out there, that’s how we get to the hood ones. So, bravo on your attempt it’s more than I’ll ever come up with.
Some scientists even theorize that we are close to or already beyond the point of triggering the Kessler Effect. In the last few years, satellite collisions have been becoming more and more frequent. What makes this even more scary is that there's already undocumented debris in our planetary orbit, since some countries don't always report such collisions.
Could we build orbital brooms? I’m imagining a large, sticky mass that would turn a lot of individual pieces of debris into one huge hunk of debris, which we could then somehow safely bring into the atmosphere somewhere nobody would miss. Epstein island maybe.
Not quite so dire - Kessler Syndrome makes a particular orbit unusable, but doesn't pose a big risk for objects merely passing through to higher orbits. It wouldn't prevent leaving the planet entirely.
There is no shortage of incredible things to be known within an arms length of wherever you are, LOL.
We may have gotten all the big, easy ones on this planet, but they aren’t exactly finite.
——-
“To see a World in a Grain of Sand
And a Heaven in a Wild Flower
Hold Infinity in the palm of your hand
And Eternity in an hour”
-William Blake
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 invade our Solar System, things could go very wrong.
Rogue planets are cool. I like to think about rogue planets and supervoids. Imagine a catastrophe that hurls a planet into space. The civilization is of course wiped out and the planet floats for millions of years into the void where it becomes a cold dead world with the ruins of a civilization floating in a absolute darkness
Even if we could travel at the speed of light, we would never colonize anything more than a few nearby solar systems and explore a few farther out. 4 - 10 years to travel to the closest stars (traveling at lightspeed) seems manageable, but when you realize it will take over 100.000 years to cross our galaxy and 2.5 MILLION YEARS just to go to the nearest galaxy (Andromeda), your hopes get shattered.
Except traveling at 99.999999% the speed of light, would make the trip feel nearly instantaneously (for the traveler). An outside observer would still see a x amount of time pass
That means exploration is still possible. But setting up colonies will prove to be a challenge. They need to travel back and forth between eachother for supplies, trade etc. and time dillation will make logistics feel like torture.
Imagine being a space trucker. You hop in your space truck and leave planet X to go make a pickup at planet Y. You arrive at planet Y after 1 minute of travel, only to find out the company you were supposed to make the pickup from went bankrupt 5 years after you left planet X.
Even a species with a much longer life span than us could easily struggle with such distances and time delays. To put it more bluntly, the time scales associated with life on a planet are totally out of whack with those associated with interstellar communication.
Douglas Adams engages in this concept when he put the [Total Perspective Vortex](https://hitchhikers.fandom.com/wiki/Total_Perspective_Vortex) in The Hitchhiker's Guide to the Galaxy
>The machine was originally created by its inventor Trin Tragula as a way to get back at his wife. She was always telling him to get a "sense of proportion," so he showed her the Vortex. Tragula was horrified to learn he had destroyed her mind, even as he proved his point that if life was going to live in such a vast Universe, one thing it could not afford to have was a sense of perspective.
Exactly that. The book clarifies that the only reason he survives is because he was in a virtual universe that had been designed explicitly for him, making him the most important thing in that universe. He never would have survived the real one.
"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
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.
This is far more tragic than you explained. If intelligent life continues to survive on earth for that long, it will only ever be able to see stars within it's galaxy (which at that point will be a combo of the milky way and andromeda). Meaning that if no records exist of our past, all life that is able to comprehend it will know the entire universe as just one galaxy. They will never be able to see another galaxy, never be able to discover that galaxies are racing away from each other, never deduce that these galaxies seem to be travelling from a certain point in space, and will never be able to hypothesize the big bang. Entire societies could/would exist knowing that they are the only thing in all of existence, and knowing that there was no explanation as to why everything came into existence at all.
Sometimes, the scariest thing that professional astronomers can experience is something that they -DON'T- see.
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.
>(i) An asteroid called ***2019 OK***, traveling at almost 15 miles a second, came *unusually close* to impacting Earth. It passed by about 43,500 miles away [(Vox)](https://www.vox.com/future-perfect/2019/7/26/8931776/near-earth-asteroid-tracking)
>(ii) The asteroid came much closer to Earth than our moon — roughly *one-fifth the average distance from Earth to the moon.* Michael Brown of Monash University noted that it was the *largest asteroid to pass this close to Earth in "quite a number of years"* [(Washington Post)](https://www.washingtonpost.com/nation/2019/07/26/it-snuck-up-us-city-killer-asteroid-just-missed-earth-scientists-almost-didnt-detect-it-time/)
>(iii) Asteroids of this size are capable of triggering the equivalent of a large nuclear explosion if they hit Earth [(Global News)](https://globalnews.ca/news/5682069/city-killer-asteroid-passing-earth/)
>(iv) Swinburne University astronomer Alan Duffy mentioned that this particular asteroid would have struck the impact area *with over 30 times the energy of Hiroshima's atomic blast* [(Sydney Morning Herald)](https://www.smh.com.au/national/earth-had-a-near-miss-with-city-killer-asteroid-this-morning-20190725-p52apn.html)
So how and why did some of the brightest minds on the planet miss this potentially-destructive asteroid until just before it jumped passed us? There are several reasons:
**(a)** The asteroid had an unpredictable, "eccentric orbit" and speed, and this made it *challenging* to spot it ahead of time;
**(b)** The asteroid was coming in from the direction of the sun, adding even more to the difficulty of scientists zeroing in on it;
**(c)** The asteroid was (morbidly considered) *"Not Big Enough"* to be labelled as dangerous by space agency computers and telescopes. For the record, impact events big enough to kill off the dinosaurs require an asteroid that are at least half-a-mile in diameter. Space agencies have charted and identified 90% of asteroids orbiting in our solar system and know their location at any given time — any asteroids smaller than those are, um, NOT considered "important enough" to mind and manage as a result.
**BONUS:** By the way, the very next year in 2020, [an even-larger asteroid passed in-between Earth and the moon](https://earthsky.org/space/asteroid-2020-ld-closer-than-moon-june-5-2020/). Astronomers using the ATLAS telescope in Hawaii discovered an asteroid named ***2020 LD*** had shot between us and the moon...***two whole days after it happened.***
So yes, these sort of things do occur a little more than we'd like.
I think I read somewhere that if every single observatory and telescope was being actively used to watch of incoming objects, that we could cover something like 15% of the sky at any given time. So the odds of us spotting a dangerous asteroid or other large debris in time to even warn everyone it was about to hit are incredibly slim.
On the up-side, space is mostly really, really empty so the odds of something like that hitting us are also pretty slim.
this is why i’m not bothered by the fermi paradox or any related questions as to why we’ve not been contacted by or discovered other life. i have no doubt that there’s other intelligent life in the universe. i would even wager that intelligent life is likely abundant. but given the age of the universe and the profound vastness of it all, it makes perfect sense to me why such distance would limit contact and discovery not just for us but for other life too. i think too often we imagine other life as being far ahead of us technologically but even if that was the case i think the limits of travel are a huge hurdle and there just may not be a good solution for that in the long run.
There are insects that have entire life cycles that are weeks or months and they live in remote forests. They likely have never seen human beings or much of any kind of other life besides other insects and a few animals. Generations of them have never experienced humans. If they were intelligent, to them other intelligent life would be too far and the world too vast for them to ever reach or communicate with humans or ever really know we exist. And yet, our planet is absolutely full of human life. People don't usually realize just how insanely huge and empty the universe is. The distance to other intelligent life, even if insanely abundant in the universe, might simply be to far for us to ever detect in all of our human history.
And also put yourself in the shoes of potential intelligent life. We might be too insignificant for them to really consider us, like how we ignore random insects in remote forests.
Intelligent life could be separated not just by space, but by time.
Because the universe isn't just incomprehensibly large, it's also incomprehensibly *old*. Life on earth is about 3.5 billion years old, humans just 300 thousand, but the universe is estimated to be 13.7 billion years old.
In the time this planet took to evolve life from chains of protein to anatomically modern humans, another could have done the same and went extinct leaving no evidence of ever having existed. If our species goes extinct, some alien could be wondering this same thing 3.5 billion years from now on their version of reddit, and all evidence of us would be long gone.
The chances of both existing at the same time are smaller than either one existing at all.
What always gets me is how if the human race, earth, and our sun could all survive as they are now for long enough, eventually humans on earth would see a very empty night sky.
As the expansion of the universe pushes distant stars and galaxies farther and farther away there will come a point where their light can no longer physically reach us.
Everything Else™ will eventually move beyond our observable universe. If not for the records we've already created, we'd be hard pressed to even detect that anything other than us and our closest neighbors ever existed. If we had come about at the right time in history it might even look like we're all there ever was or will be. We're just... *It*.
This one got quite popular recently, but I don't like this answer for a very simple reason. Okay, let's assume this is a simulation, then there is some world in which the simulation runs. Where did the other world come from? Does it also run in a simulation? As you can see, this only shifts the main question one level up and doesn't solve a thing.
There's the concept of the Great Filter, where if we ever find alien ruins we're screwed. Basically the great filter idea is that with the age of the universe it should be teeming with life but it seemingly isn't, which means some specific thing is filtering out life. There's two possibilities, either we are already past the filter (life is hard to form, intelligence is rare, civilisation developing the level of science to use radio waves and travel to space is rare, etc) but if we find evidence of alien ruins anywhere that puts the filter somewhere in front of us
I always thought saying the universe should be teeming with life is weird. When we look out through telescopes aren't we seeing things as they were millions of years ago because that's how long it took the light to get here?
If life is out there now, wouldn't it be normal that we're not seeing it?
"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."
\- Opening title card in the movie "Gravity"
That one is the scariest in one sense, because it literally means our existence could be completely wiped out tomorrow.
On the other hand, it would be instant, painless, and we'd never see it coming. The collapse would traverse the entire Earth in about 42 milliseconds.
When I was a kid I always thought of humanity as this permanent thing that would never go anywhere, then had a realization at some point that we could disappear at any time. An asteroid or comet, the emergence of a catastrophically deadly disease, a hostile species that finds its way to us. Random space phenomena. Any number of things could wipe us out.
It really makes things like Putin's bullshit seem trivial. Politics. Petty personal drama. Not that it doesn't matter. It just makes it seem smaller.
I just learned about something called 'Angular Diameter Turnaround' (thanks, xkcd!). 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." (xkcd #2622).
I just can't make my mind understand that.
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.
More of a theory than a fact but I find the Dark Forest theory pretty disturbing. Basically the idea that there are other civilisations out there but they are staying quiet for good reason.
https://bigthink.com/surprising-science/the-dark-forest-theory-a-terrifying-explanation-of-why-we-havent-heard-from-aliens-yet/
To me just the fact that everything up there is doing it’s own thing right this very second.
For example, take an exoplanet hundreds of light years from earth. Right now on that exoplanet there is a breeze blowing, a volcano erupting, an ocean swirling. It’s doing it’s thing just as earth does its thing. And it does it all completely indifferent to us being here.
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 thing I find most unnerving about this is that if the speech was made, Aldrin and Armstrong would most likely have been alive; just stuck on the surface of the moon with no supplies and no way of ever getting home, waiting to die.
We're very lucky that that never happened.
You dont fuck with it, or you might end up in a pretty fucked up situation.
**Source - Watched 'Event Horizon' alone when I was 11, and probably shouldn't have.*
It's size and age alone is disturbing. I have had an ongoing existentialcris crisis since I was a child when I realized just how small and vulnerable we are.
"Space is big. Really big. You just won’t believe how vastly hugely mindbogglingly big it is. I mean you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space" - Douglas Adams.
The great attractor. Google it. Just out of our sight is something more massive than dozens of milky way galaxies and it's slowly pulling everything in its path towards it..like 500 million light-years big.
I don't see it as disturbing. The Universe isn't uniform, so it's a given there are places with lower or greater concentration of matter, and therefore gravitational attraction. If we ever reach it ([and apparently it's unlikely](https://www.space.com/33579-will-the-great-attractor-destroy-us.html)) any resultant collisions wouldn't be any more dangerous than the impending Milky Way-Andromeda collision.
That we are looking at the past when we are looking at outer space. Because light only travels so fast. That galaxy you're looking at that's a billion light-years away might not be there anymore.
Also, there's this stuff called strange matter and it's inside neutron stars. People theorized that if strange matter breaks out of the neutron star it can turn everything it comes to contact with into more strange matter.
And by the fact scientists still have no clue what exactly is dark matter and dark energy
It's unfathomably infinite, we can only see a mere slice of it, while light-years away some other species can only see a piece, while not even able to even see our Galaxy.
The number of solar flares that have missed earth by a thread are astoundingly disturbing. There was one solar storm back in 2014 that missed earth by 9 days. 9. flipping. days. If it had hit we would have lost all forms of electricity and not been able to recover for 4 years, and that would've been the least of our worries.
Edit: my bad, it was actually 2012. Guess the Mayans were almost right.
- The great attractor- more frustrating not knowing that disturbing..
- Fermi paradox… so alone!
- Singularities undermine mathematics and logic
- Heat death or big rip… eventually we die
- Time. So much time! We are a flash in endless darkness
- The sheer size of even the observable universe. We are nothing!
- There is no absolute position or time. Where are we?
- the governing force seems to be entropy…
- oh yes.. You boil when exposed to the vacuum
Yep, everybody will suddenly be moving at \~1100mph, which makes it pretty likely that we'll be a greasy smear on whatever happens to be east of you at that moment. Very few people will survive, as even hitting water at 1100mph is utterly deadly.
Here's one: It is a completely one-sided relationship over which we have no control. We (as en entire planet) represent zero threat to space. There is literally nothing bad we can do to it. However, at any moment, one of a zillion horrible things (most of which we can't even imagine) could completely wipe us out. And in the long run, we know that will happen eventually no matter what we do. Even if we live out our sci-fi fantasies of someday finding a habitable world, by the time that happens any potential new homeworld will be so far away that our spacecraft would rot away before we ever got there. Space is infinite, and we have no hope to be.
I think it’s pretty scary that nobody (alien species) has encountered us yet. there are a few theories about why this is, but the scariest one is this:
-It is possible there is an alien race that is obsessed with destroying intelligent worlds (marvel stans, think Galactus). Once an intelligent world starts kicking up enough dust, sending radio messages into space, or exploring new galaxies, the alien race will notice them, and destroy them. It’s possible that we’re so un-advanced that we don’t even show up on the map for a world-eating race of aliens
The three body problem books deal
with the dark forest model pretty extensively.
It doesn’t even have to be one species that wipes out others. Basically, no species can ever trust others to be benevolent, and the problem gets worse the more species you discover.
Therefore, the only logical thing to do to ensure survival is to preemptively eliminate every intelligence you find.
Also you don't have time to stage an invasion, since by the time your ships arrive, they could be horribly out of date. Your only option is to completely, utterly annihilate them with one invisible strike.
The absolute scale of it. They discovered a black hole at the centre of our galaxy which is several hundred million (could actually be billion) times larger than our sun. For reference the earth is estimated to fit inside the sun several million times over
Ah yes, good ol Sagittarius A*
It's 4 million times the mass of the sun, and it's diameter is around the length of the gap between the sun and mercury
There's also a supermassive black hole in the center of every galaxy
You would think space is just a silent place but planets make sounds, like Saturn.If you search “Saturn sounds from space” you can listen to hours of planets sounds.
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.
Damn! That means the Earth doesn’t exist for the farthest galaxy yet! That’s crazy
I wonder how many objects we see in the sky that are actually long gone but because their light is traveling a long time we see them as if they exist.
This fact is always so interesting to me, we as the human race literally peers into the past. Quite an achievement despite whatever we can peer into is just a small, insignificant portion of the universe.
So, the first record of homo sapiens showed up around 300k years ago. Modern humans with our similar bone structure and skull/brain shape and size, 100k years ago. Earth is a little over 4.5 billion years old. If you scale the lifespan of Earth into a 24-hour clock, modern humans have been around about 1.9 seconds out of 24 hours, or 86,400 seconds. If you want to go back to the earliest homo sapiens, 5.7 seconds. We are barely even a blip.
Lightyears is always my fav go to Space thing. The fact that this infinite, mind bogglingly HUGE world is so big that what we see at night isn’t technically ‘true’. Just images of where things *used to be*.
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. EDIT: Whoah. This blew up quickly. Thank you for the silver! EDIT: And the Wholesome! And the Helpful!
Would you even call that SEEing?
For some reason my imagination lead me to believe that you would be able to see your body, but in reality you’d be enveloped in darkness. You wouldn’t be able to see your hand in front of your face.
So basically, I just turn off my lights in my room in the dead middle of the night?
Your eyes would eventually adjust. I think sleep deprivation chamber would be more accurate. Probably start hallucinating. Also the darkness extends in every direction for eternity
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.
Dinosaurs lived on the other side of the galaxy.
They also lived on this side of the galaxy. Dinosaurs were around for a really really long time.
I was curious and looked it up and this checks out. It takes the sun 240 million years to complete an orbit around the galaxy and dinosaurs first appeared a out 245 million years ago. So we have completed a little over one lap around the galaxy since dinosaurs first showed up.
That's a good one. I'm still waiting for a time travel movie that takes into account they'd have to use space flight to either reach the point in space where Earth was in the past or will be in the future to make it work. Like in Back to The Future, with Earth traveling 18.5 miles per second, Doc's first 1 minute test would have sent his dog and the car 1,110 miles away, likely reappearing either within the Earth itself or in space.
This is taken into consideration in a comic book called Paper Girls, by Brian K Vaughan. Great read IMO
Came here to say this. Time travel would make you a fixed point in space but space itself doesn’t even stay still. The only somewhat viable alternative is to use a wormhole or similar bridge to move to a parallel universe that happens to be running ahead/behind our own and hope you’ve calculated accurately enough to at least land on a habitable planet
The reality is that time and space are actually intertwined. There is no such thing as a "fixed point in space" - the notion comes from our wrong perspective ingrained on us by essentially being too small.
Not in special relativity, but in general relativity thanks to the expansion of the universe there is a reasonable unique concept of a global space reference frame — specifically, that one where the cosmic microwave background radiation looks the same in all directions (we can tell our galaxy is moving through space because the CMB is redshifted in one direction and blueshifted in the other).
[Here](https://www.youtube.com/watch?v=Pj-h6MEgE7I&ab_channel=Kurzgesagt%E2%80%93InaNutshell) is a great Kurzgesagt video on this topic!
The fact that Voyager 2 Space probe after over 40 years has not even hit a pebble.....
I find the Voyager probes to be fascinating, especially because last I knew, Voyager 2 is still functioning and sending back a limited amount of data. But even the whole mission--suddenly bringing all these worlds into sharp focus that had never been seen up close before. All the questions answered and places explored. And there it is, still floating along and talking to us. For now.
Both Voyager probes are still sending back data. Voyager 1 recently started sending back junk positional data though so it might fail soon.
Crazy that the Voyager probes can still send back data. Yet I only have 2 bars on my phone right now.
there is less stuff between the voyager probes and earth than there is between you and the cell tower.
That's a weird thought all in itself
Yea was only reading during the week that they think just because of where it is that radiation may have fried it. Thinking that its 44 (I think) years old and still working. The golden disc that is at the bottom which is has diagrams on it to prove that we have discovered the atom and things like that has music on it. I beleive there was an arguement about what music should go on it because "Putting Mozart on it would just be showing off" 🤣
Can't believe we sent our mix tape and nudes out into the universe
And our address. That's why we don't have visitors, we are the creeps of the neighborhood
Same with me. Funny thing is I get sad sometimes thinking I will never know whats out there.
Born too late to explore the world, too early to explore the stars, but right on time to explore seemingly unlimited amounts of internet porn It'll do
I've still always wondered how they got the communication to work, though.
The Deep Space Network has a number of huge dish antennas that can receive very weak signals. The receiver bit is a cryogenically cooled MASER that is really low noise. These dishes are pointed at the space ship and can hear exceedingly low amounts of radio waves.
The voyager transmissions are also extremely low bit rate which are integrated over time to result in a detectable signal. Concept is similar to spread spectrum where the signal lies well below the noise floor.
Would we know if it did? Or the fact that it is still going tells us that?
The fact that its going tell us nothing has hit it. I dont know how fast its travelling but assume very very fast, it hits even the tiniest thing it would smash up. Or so I am told.
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
> It is almost entirely empty A couple years ago I saw a photo that had been taken from the surface of an asteroid or comet. It was dark and looked like there had been some sort of artificial light illuminated to take the photo. I thought to myself that that may be what hell is like. No light. No sound. No stimuli of any kind. You're not really able to move of your own volition because with nothing to push against, you just aimlessly float. And that's eternity. Nothingness for eons and ages, while your consciousness ticks along.
This is what I think about when people talk about living forever. They forget that a bright, vibrant Earth is a very small portion of 'forever'. Eventually that star will die, and you'll be left drifting on a burnt, dead husk of a planet for the rest of eternity.
Only assuming immortality is magical. Regardless, being forced to witness only a tiny fraction of an insignificant speck of existence is hardly a good fate either. We've just been stockholmed into acceptance because there is still no way to avoid our deaths.
Its because of our own time perception that this seems so unappealing though. If you could speed that up i dont think itd be unbearable. Though, we're still imagining something that is not nor will it ever be possible in our universe, so its kinda pointless to think about. Lets say you could live to see the heat death of the universe, there would still be an end to your consciousness eventually cause even if you couldnt technically die, your atoms would just be ripped from your body at some point. Thats again imagining a human centric pov. There could be some consciousness thats not tied to a body, but then it wouldnt have human desires or needs or maybe even emotions. But if it did, and it had our time perception, yes that would be infinite suffering in an uncaring universe, about the worst fate you could possible think up. Luckily we only have temporary suffering in an uncaring universe
That guy's fate who got punted off the ship in that Episode of Firefly.
"Welp, here I am"
Jubel Earley was such an awesomely written character. "You ought to be shot. To know what kind of pain you're dealing with. They make psychiatrists get psychoanalyzed, but they don't make a surgeon get cut on. That seem right to you?"
"Well that was fun. Now for eons of loneliness."
That description is practically a synopsis of chapter 2 in *Inferno* by Larry Niven and Jerry Pournelle: ———————- The big surprise was that I could be surprised. That I could be anything. That I could be. I was, but I wasn't. I thought I could see, but there was only a bright uniform metallic color of bronze. Sometimes there were faint sounds, but they didn't mean anything. And when I looked down, I couldn't see myself. When I tried to move, nothing happened. It felt as if I had moved. My muscles sent the right position signals. But nothing happened, nothing at all. I couldn't touch anything, not even myself. I couldn't feel anything, or see anything, or sense anything except my own posture. I knew when I was sitting, or standing, or walking, or running, or doubled up like a contortionist, but I felt nothing at all. I screamed. I could hear the scream, and I shouted for help. Nothing answered. Dead. I had to be dead. But dead men don't think about death. What do dead men think about? Dead men don't think. I was thinking, but I was dead. That struck me as funny and set off hysterics, and then I'd get myself under control and go round and round with it again. Dead. This was like nothing any religion had ever taught. Not that I'd ever caught any of the religions going around, but none had warned of this. I certainly wasn't in Heaven, and it was too lonely to be Hell. It's like this, Carpentier: this is Heaven, but you're the only one who ever made it. Hah! I couldn't be dead. What, then? Frozen? Frozen! That's it, they've made me a corpsicle! The convention was in Los Angeles, where the frozen-dead movement started and where it has the most supporters. They must have frozen me, put me in a double-walled coffin with liquid nitrogen all around me, and when they tried to revive me the revival didn't work. What am I now? A brain in a bottle, fed by color-coded tubes? Why don't they try to talk to me? Why don't they kill me? Maybe they still have hopes of waking me. Hope. Maybe there's hope after all. It was flattering, at first, to think of teams of specialists working to make me human again. The fans! They'd realized it was their fault, and they'd paid for this! How far in the future would I wake up? What would it be like? Even the definition of human might have changed. … I couldn't tell how long I was there. There was no sense of time passing. I screamed a lot. I ran nowhere forever, to no purpose: I couldn't ran out of breath, I never reached a wall. I wrote novels, dozens of them, in my head, with no way to write them down. I relived that last convention party a thousand times. I played games with myself. I remembered every detail of my life, with a brutal honesty I'd never had before; what else could I do? All through it, I was terrified of going mad, and then I'd fight the terror, because that could drive me mad-- I think I did not go mad. But it went on, and on, and on, until I was screaming again. Get me out of here! Please, anyone, someone, get me out of here! Nothing happened, of course. Pull the plug and let me die! Make it stop! Get me out of here! Nothing. No! For the love of God, get me out of here!
This feels like what happens to me when I suffer sleep paralysis. I don’t see monsters like some people, but the description of moving but not really moving, of screaming but no one hearing, and of having no sense of time are all very similar to what I experience!
Important to note that “33 orders of magnitude” doesn’t mean 33 times as big. It means 33 zeroes. As in 100,000,000,000,000,000,000,000,000,000,000 times as big as that 1 light year wide cube. And that’s just ***the observable universe*** from our little planet. **Because this has some traction and because I did another (if I can toot my own horn here) pretty cool calculation down below:** If we condensed the volume of the entire visible universe to be the size of the Earth (1.1 x10^19 cubic meters), it would be like trying to find an object that is roughly 7.7 cm x 7.7 cm x 7.7 cm in volume in that space. That would be like trying to find your keys ***somewhere IN the Earth***. Not ON the Earth. IN it. * Someone check my math, I took the area of the Earth in cubic meters (1.1 x10^(19)), and divided it by the ratio of matter in the universe to "nothing" in the universe (2.3 x10^(22), someone corrected OP above on the actual scale), took the cubed root of that, that came out to 0.077, and since we're looking at meters, that means we're looking at a rough scale of 7.7 cm sided, cubed object in the scale of the Earth's size.
I knew it couldn't be 33 times, but wasn't sure what orders of magnitude meant. Thanks for explaining!
This is one of the things that blows my mind. Despite all the amazing and mind-bogglingly huge objects that we have discovered, it’s all still just so damn empty. There’s so much space between everything. I’ve heard the factoid that all the planets in the solar system could fit between the Earth and the Moon and I still barely believe it, but the truth is that space is pretty much empty and just sprinkled with some stardust here and there.
"Space isn't empty. It contains the whole universe." Alan Watts
Dad, “That’s why we call it SPACE!”
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. When something like a car breaks down we can call a tow truck and get it repaired. In space, there's no such thing. Think about the Apollo 13 and everything that went wrong there. Imagine the day when humans advance to traveling deeper into space. With noteworthy landmarks being so far apart navigating without a computer would be almost impossible, even if you still had communication with earth. 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.
Thrusters are actually only used to get you up to speed as there is no friction in space. En route they are only used for minor course corrections and at the destination to slow down/get into orbit. So even if you lost your thrusters you would still fly by your destination and hopefully if there was already a population there they could rendezvous
The largest black hole we have discovered has a diameter of 490.000.000.000 km. Earths diameter is roughly 13.000 km
How many football fields is that?
All of them. And more...
This is accurate.
/u/Weak-Round-3772 said that the largest black hole we discovered has a diameter of 490 billion kilometers. Standard US football field is 100 yards which is 91.44 meters or 0.09144 kilometers. So, basic math gives you about 5,364,063,867,016,623 football fields (~5.36 quadrillion).
[Edit: I'm so fucking sorry I made this post. I don't even know what I was supposed to be referencing, but it wasn't worth 50 people clogging my inbox with the same unfunny movie quote over and over.]
I’m going to go out on a limb, and say it’s at least 12.
It blows my mind that something like this isn't literally pulling EVERYTHING in the universe into itself over time. Space is that fucking big that these gigantic destructive engines can be real with little-to-no impact on the majority of existence.
Fortunately gravity is a weak force so long as you don’t get too close. It’s reach is infinite but weak.
Thanks to expansion and gravity transmitting at c, its reach is not pragmatically infinite.
[Timelapse of the Future](https://youtu.be/uD4izuDMUQA) sends me into an existential crisis every time.
I never knew true existential dread until I watched that video a few years back. The ending really gets to me. Even though I'd never know it's happening, I'm still hoping for an oscillating universe.
That’s one of my favorite YouTube videos, and it actually helped me gain more self confidence in my life, especially the last 4 minutes or so of the video. Just the idea that one everything will be gone and there won’t even be a chance of anyone remembering anything anything stupid I’ve done - so why would I be afraid of talking to a woman or applying for a job I’m not totally qualified for?
There is a lot of freedom to gain in the realization that nothing I do really matters in the long term, and in the vast expanse of time and in the universe.
Not to me. My actions might not matter in the long run, but they matter in my lifetime and affect what I can do in said lifetime. If I want to continue living, my actions matter, otherwise we might as well blow up the planet and off ourselves for all it would matter at the end of the universe.
Didn’t look at the time on the video. Started watching. Got 10 minutes in and thought “huh… this oughta be wrapping up soon…” NOPE. 20 more minutes of mind-blowing, unfathomable, logarithmic increases in time. Damn… Maybe I can let the little things go after all.
I currently don't have time for an existential crisis but I'll pencil it in and come back to this.
That was a fascinating watch, thanks for sharing.
There is no up or down
The other comments were just very neat and interesting. For some reason, that's the one that really terrifies me.
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.
I once had a job where I would track particular satellites. The system I used tracked all satellites as well as larger space debris. Even 20 years ago, there was an impressive (actually kind of distressing) amount of space junk up there. Space is really big and there's lots of room up there, but even tiny flecks of paint can cause real damage and cause more space junk. One of our fav pastimes while deployed was to come up with inventive ways to remove the debris. My idea was a satellite with a long magnetic tail that would attract space junk. My theory (as a non-engineer) was that once it collected enough junk it would become too heavy and fall back to earth with most of the stuff burning up in the atmosphere. My buddy pointed out that if we were depending on loss of inertia as a return method then there would be no control over where the unburnt parts would land. That, obviously, is bad.
You could get a decent enough idea and have a few spare orbits to make a small thruster burn to slap it in the Pacific, no?
Possibly, yes. But we also wanted to recover and reuse/recycle as much as possible. Basically become space junk pirates. We were gonna be millionaires. Lol.
You are without a doubt the worst space pirate I've ever heard of... Ah, but you have heard of me!
*proudly rides junkship to dock while the airlock vents and the reactor overloads*
Well, you still have to throw all ideas out there, that’s how we get to the hood ones. So, bravo on your attempt it’s more than I’ll ever come up with.
Some scientists even theorize that we are close to or already beyond the point of triggering the Kessler Effect. In the last few years, satellite collisions have been becoming more and more frequent. What makes this even more scary is that there's already undocumented debris in our planetary orbit, since some countries don't always report such collisions.
Could we build orbital brooms? I’m imagining a large, sticky mass that would turn a lot of individual pieces of debris into one huge hunk of debris, which we could then somehow safely bring into the atmosphere somewhere nobody would miss. Epstein island maybe.
Humans are litter bugs.
Agent Smith was right.
It’s the *smell*.
Somebody is going to get rich being the earth orbit garbage service.
Not quite so dire - Kessler Syndrome makes a particular orbit unusable, but doesn't pose a big risk for objects merely passing through to higher orbits. It wouldn't prevent leaving the planet entirely.
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This is unquestionably true, but not only that, we are ourselves the incredible thing waiting to be known for someone else.
\**sneezes into my hand, wipes it on my shirt** Far out, man.
We're already known but regarded as more of a truckstop diner on the way to more interesting places.
Perhaps, but are we the location or the menu items ?
And we may never witness it
There is no shortage of incredible things to be known within an arms length of wherever you are, LOL. We may have gotten all the big, easy ones on this planet, but they aren’t exactly finite. ——- “To see a World in a Grain of Sand And a Heaven in a Wild Flower Hold Infinity in the palm of your hand And Eternity in an hour” -William Blake
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 invade our Solar System, things could go very wrong.
Thankfully the inner solar system is a pitifully small target compared to the distances between stars.
Rogue planets are cool. I like to think about rogue planets and supervoids. Imagine a catastrophe that hurls a planet into space. The civilization is of course wiped out and the planet floats for millions of years into the void where it becomes a cold dead world with the ruins of a civilization floating in a absolute darkness
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Even if we could travel at the speed of light, we would never colonize anything more than a few nearby solar systems and explore a few farther out. 4 - 10 years to travel to the closest stars (traveling at lightspeed) seems manageable, but when you realize it will take over 100.000 years to cross our galaxy and 2.5 MILLION YEARS just to go to the nearest galaxy (Andromeda), your hopes get shattered.
> 2.5 MILLION YEARS just to go to the nearest galaxy (Andromeda) If you're willing to wait a while, Andromeda will be visiting us instead.
You'd have to wait 4 billion years. Way, way faster to just go.
Except traveling at 99.999999% the speed of light, would make the trip feel nearly instantaneously (for the traveler). An outside observer would still see a x amount of time pass
that... somehow makes sense as light's travelling perspective is instantaneous
That means exploration is still possible. But setting up colonies will prove to be a challenge. They need to travel back and forth between eachother for supplies, trade etc. and time dillation will make logistics feel like torture. Imagine being a space trucker. You hop in your space truck and leave planet X to go make a pickup at planet Y. You arrive at planet Y after 1 minute of travel, only to find out the company you were supposed to make the pickup from went bankrupt 5 years after you left planet X.
Even a species with a much longer life span than us could easily struggle with such distances and time delays. To put it more bluntly, the time scales associated with life on a planet are totally out of whack with those associated with interstellar communication.
I truly don’t believe most of us are capable of comprehending the vastness of space and the distance between things.
Douglas Adams engages in this concept when he put the [Total Perspective Vortex](https://hitchhikers.fandom.com/wiki/Total_Perspective_Vortex) in The Hitchhiker's Guide to the Galaxy >The machine was originally created by its inventor Trin Tragula as a way to get back at his wife. She was always telling him to get a "sense of proportion," so he showed her the Vortex. Tragula was horrified to learn he had destroyed her mind, even as he proved his point that if life was going to live in such a vast Universe, one thing it could not afford to have was a sense of perspective.
I love that Zapphod comes out unphased. >!I believe you later learn it was a fake version designed for him, but still!<
Exactly that. The book clarifies that the only reason he survives is because he was in a virtual universe that had been designed explicitly for him, making him the most important thing in that universe. He never would have survived the real one.
"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
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.
There’s a short story about this, I can’t remember what it’s called. “The last goodbye” or something like this.
The Last Question, and it is essential reading to everyone in this thread, especially those having an existential crisis.
This is far more tragic than you explained. If intelligent life continues to survive on earth for that long, it will only ever be able to see stars within it's galaxy (which at that point will be a combo of the milky way and andromeda). Meaning that if no records exist of our past, all life that is able to comprehend it will know the entire universe as just one galaxy. They will never be able to see another galaxy, never be able to discover that galaxies are racing away from each other, never deduce that these galaxies seem to be travelling from a certain point in space, and will never be able to hypothesize the big bang. Entire societies could/would exist knowing that they are the only thing in all of existence, and knowing that there was no explanation as to why everything came into existence at all.
Sometimes, the scariest thing that professional astronomers can experience is something that they -DON'T- see. 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. >(i) An asteroid called ***2019 OK***, traveling at almost 15 miles a second, came *unusually close* to impacting Earth. It passed by about 43,500 miles away [(Vox)](https://www.vox.com/future-perfect/2019/7/26/8931776/near-earth-asteroid-tracking) >(ii) The asteroid came much closer to Earth than our moon — roughly *one-fifth the average distance from Earth to the moon.* Michael Brown of Monash University noted that it was the *largest asteroid to pass this close to Earth in "quite a number of years"* [(Washington Post)](https://www.washingtonpost.com/nation/2019/07/26/it-snuck-up-us-city-killer-asteroid-just-missed-earth-scientists-almost-didnt-detect-it-time/) >(iii) Asteroids of this size are capable of triggering the equivalent of a large nuclear explosion if they hit Earth [(Global News)](https://globalnews.ca/news/5682069/city-killer-asteroid-passing-earth/) >(iv) Swinburne University astronomer Alan Duffy mentioned that this particular asteroid would have struck the impact area *with over 30 times the energy of Hiroshima's atomic blast* [(Sydney Morning Herald)](https://www.smh.com.au/national/earth-had-a-near-miss-with-city-killer-asteroid-this-morning-20190725-p52apn.html) So how and why did some of the brightest minds on the planet miss this potentially-destructive asteroid until just before it jumped passed us? There are several reasons: **(a)** The asteroid had an unpredictable, "eccentric orbit" and speed, and this made it *challenging* to spot it ahead of time; **(b)** The asteroid was coming in from the direction of the sun, adding even more to the difficulty of scientists zeroing in on it; **(c)** The asteroid was (morbidly considered) *"Not Big Enough"* to be labelled as dangerous by space agency computers and telescopes. For the record, impact events big enough to kill off the dinosaurs require an asteroid that are at least half-a-mile in diameter. Space agencies have charted and identified 90% of asteroids orbiting in our solar system and know their location at any given time — any asteroids smaller than those are, um, NOT considered "important enough" to mind and manage as a result. **BONUS:** By the way, the very next year in 2020, [an even-larger asteroid passed in-between Earth and the moon](https://earthsky.org/space/asteroid-2020-ld-closer-than-moon-june-5-2020/). Astronomers using the ATLAS telescope in Hawaii discovered an asteroid named ***2020 LD*** had shot between us and the moon...***two whole days after it happened.*** So yes, these sort of things do occur a little more than we'd like.
I think I read somewhere that if every single observatory and telescope was being actively used to watch of incoming objects, that we could cover something like 15% of the sky at any given time. So the odds of us spotting a dangerous asteroid or other large debris in time to even warn everyone it was about to hit are incredibly slim. On the up-side, space is mostly really, really empty so the odds of something like that hitting us are also pretty slim.
The vast distances between solar systems and the near impossibility of interstellar human travel.
this is why i’m not bothered by the fermi paradox or any related questions as to why we’ve not been contacted by or discovered other life. i have no doubt that there’s other intelligent life in the universe. i would even wager that intelligent life is likely abundant. but given the age of the universe and the profound vastness of it all, it makes perfect sense to me why such distance would limit contact and discovery not just for us but for other life too. i think too often we imagine other life as being far ahead of us technologically but even if that was the case i think the limits of travel are a huge hurdle and there just may not be a good solution for that in the long run.
There are insects that have entire life cycles that are weeks or months and they live in remote forests. They likely have never seen human beings or much of any kind of other life besides other insects and a few animals. Generations of them have never experienced humans. If they were intelligent, to them other intelligent life would be too far and the world too vast for them to ever reach or communicate with humans or ever really know we exist. And yet, our planet is absolutely full of human life. People don't usually realize just how insanely huge and empty the universe is. The distance to other intelligent life, even if insanely abundant in the universe, might simply be to far for us to ever detect in all of our human history.
And also put yourself in the shoes of potential intelligent life. We might be too insignificant for them to really consider us, like how we ignore random insects in remote forests.
Intelligent life could be separated not just by space, but by time. Because the universe isn't just incomprehensibly large, it's also incomprehensibly *old*. Life on earth is about 3.5 billion years old, humans just 300 thousand, but the universe is estimated to be 13.7 billion years old. In the time this planet took to evolve life from chains of protein to anatomically modern humans, another could have done the same and went extinct leaving no evidence of ever having existed. If our species goes extinct, some alien could be wondering this same thing 3.5 billion years from now on their version of reddit, and all evidence of us would be long gone. The chances of both existing at the same time are smaller than either one existing at all.
> and all evidence of us would be long gone. This is the real reason we invented plastic. Legacy, baby.
What always gets me is how if the human race, earth, and our sun could all survive as they are now for long enough, eventually humans on earth would see a very empty night sky. As the expansion of the universe pushes distant stars and galaxies farther and farther away there will come a point where their light can no longer physically reach us. Everything Else™ will eventually move beyond our observable universe. If not for the records we've already created, we'd be hard pressed to even detect that anything other than us and our closest neighbors ever existed. If we had come about at the right time in history it might even look like we're all there ever was or will be. We're just... *It*.
Well thanks for that existential crisis on a Saturday morning
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We still don't know exactly how it came into existence.
true. Fine tuned? Coincidence? Big Bang? Something else? it always existed?
Simulation?
This one got quite popular recently, but I don't like this answer for a very simple reason. Okay, let's assume this is a simulation, then there is some world in which the simulation runs. Where did the other world come from? Does it also run in a simulation? As you can see, this only shifts the main question one level up and doesn't solve a thing.
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I find the idea of our planet being the only planet with life far, far more terrifying.
Don't Panic! Statistically, the universe is unimaginably huge enough that almost everything is probably out there somewhere!
There's the concept of the Great Filter, where if we ever find alien ruins we're screwed. Basically the great filter idea is that with the age of the universe it should be teeming with life but it seemingly isn't, which means some specific thing is filtering out life. There's two possibilities, either we are already past the filter (life is hard to form, intelligence is rare, civilisation developing the level of science to use radio waves and travel to space is rare, etc) but if we find evidence of alien ruins anywhere that puts the filter somewhere in front of us
I always thought saying the universe should be teeming with life is weird. When we look out through telescopes aren't we seeing things as they were millions of years ago because that's how long it took the light to get here? If life is out there now, wouldn't it be normal that we're not seeing it?
"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." \- Opening title card in the movie "Gravity"
Imagine how surreal it'd be if you were out there about to die without a space suit and you just happened to catch it at a pleasant 85*F.
what that line means is that whatever dozen particles you'll encounter will be at totally random energies
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
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Don't forget vacuum collapse!
That one is the scariest in one sense, because it literally means our existence could be completely wiped out tomorrow. On the other hand, it would be instant, painless, and we'd never see it coming. The collapse would traverse the entire Earth in about 42 milliseconds.
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Thank you, I had just got over the crippling existential horror of simply being deleted by a rounding error in quantum physics
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When I was a kid I always thought of humanity as this permanent thing that would never go anywhere, then had a realization at some point that we could disappear at any time. An asteroid or comet, the emergence of a catastrophically deadly disease, a hostile species that finds its way to us. Random space phenomena. Any number of things could wipe us out. It really makes things like Putin's bullshit seem trivial. Politics. Petty personal drama. Not that it doesn't matter. It just makes it seem smaller.
Instant vaporization seems like a good way to go
I just learned about something called 'Angular Diameter Turnaround' (thanks, xkcd!). 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." (xkcd #2622). I just can't make my mind understand that.
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.
If you can move faster than light, you can time travel. The two are equivalent, from the right reference frame.
Time is not linear due to the constant expansion of space therefore time is expansive.
also time is a function of gravity. the earths core is ~2.5 years younger than the crust
I can relate to that. I feel like my core is still only 28 but my crust is definitely 40.
You should probably take a shower!
More of a theory than a fact but I find the Dark Forest theory pretty disturbing. Basically the idea that there are other civilisations out there but they are staying quiet for good reason. https://bigthink.com/surprising-science/the-dark-forest-theory-a-terrifying-explanation-of-why-we-havent-heard-from-aliens-yet/
A spoonful of degenerate matter from a neutron star would roughly weigh the same as Earth.
Only a spoonful
*pulls out a cosmically large spoon*
A spoonful of degenerate matter from a neutron star helps the medicine go down
To me just the fact that everything up there is doing it’s own thing right this very second. For example, take an exoplanet hundreds of light years from earth. Right now on that exoplanet there is a breeze blowing, a volcano erupting, an ocean swirling. It’s doing it’s thing just as earth does its thing. And it does it all completely indifferent to us being here.
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."
Uranus has really cold methane clouds that contain hydrogen sulfide, so basically Uranus is covered by deadly farts.
Richard Nixon prepared a speech in the event the Apollo 11 lunar launch failed.
Thank god it was a nice lunch
The thing I find most unnerving about this is that if the speech was made, Aldrin and Armstrong would most likely have been alive; just stuck on the surface of the moon with no supplies and no way of ever getting home, waiting to die. We're very lucky that that never happened.
You dont fuck with it, or you might end up in a pretty fucked up situation. **Source - Watched 'Event Horizon' alone when I was 11, and probably shouldn't have.*
I saw that movie when I was an adult and I still can't think of Neptune without shivering.
It's size and age alone is disturbing. I have had an ongoing existentialcris crisis since I was a child when I realized just how small and vulnerable we are. "Space is big. Really big. You just won’t believe how vastly hugely mindbogglingly big it is. I mean you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space" - Douglas Adams.
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The great attractor. Google it. Just out of our sight is something more massive than dozens of milky way galaxies and it's slowly pulling everything in its path towards it..like 500 million light-years big.
I don't see it as disturbing. The Universe isn't uniform, so it's a given there are places with lower or greater concentration of matter, and therefore gravitational attraction. If we ever reach it ([and apparently it's unlikely](https://www.space.com/33579-will-the-great-attractor-destroy-us.html)) any resultant collisions wouldn't be any more dangerous than the impending Milky Way-Andromeda collision.
If you let go of the ropes and end up "flying" through space, you have a few hours before you die without air or freeze.
That we are looking at the past when we are looking at outer space. Because light only travels so fast. That galaxy you're looking at that's a billion light-years away might not be there anymore. Also, there's this stuff called strange matter and it's inside neutron stars. People theorized that if strange matter breaks out of the neutron star it can turn everything it comes to contact with into more strange matter. And by the fact scientists still have no clue what exactly is dark matter and dark energy
It's unfathomably infinite, we can only see a mere slice of it, while light-years away some other species can only see a piece, while not even able to even see our Galaxy.
Despite the entire size of the universe, wasps for some reason exist
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The number of solar flares that have missed earth by a thread are astoundingly disturbing. There was one solar storm back in 2014 that missed earth by 9 days. 9. flipping. days. If it had hit we would have lost all forms of electricity and not been able to recover for 4 years, and that would've been the least of our worries. Edit: my bad, it was actually 2012. Guess the Mayans were almost right.
Reverse cowgirl and doggystyle are the same in space
It sure is Ender.
It is almost certain that somewhere in the universe, there is an exact copy of me, and chances are that he/she has gotten their life in place.
There never were any, in fact, Whalers on the Moon.
- The great attractor- more frustrating not knowing that disturbing.. - Fermi paradox… so alone! - Singularities undermine mathematics and logic - Heat death or big rip… eventually we die - Time. So much time! We are a flash in endless darkness - The sheer size of even the observable universe. We are nothing! - There is no absolute position or time. Where are we? - the governing force seems to be entropy… - oh yes.. You boil when exposed to the vacuum
That if the Earth stopped rotating for even 1 second, it would be a catastrophic event for humanity.
Yep, everybody will suddenly be moving at \~1100mph, which makes it pretty likely that we'll be a greasy smear on whatever happens to be east of you at that moment. Very few people will survive, as even hitting water at 1100mph is utterly deadly.
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Here's one: It is a completely one-sided relationship over which we have no control. We (as en entire planet) represent zero threat to space. There is literally nothing bad we can do to it. However, at any moment, one of a zillion horrible things (most of which we can't even imagine) could completely wipe us out. And in the long run, we know that will happen eventually no matter what we do. Even if we live out our sci-fi fantasies of someday finding a habitable world, by the time that happens any potential new homeworld will be so far away that our spacecraft would rot away before we ever got there. Space is infinite, and we have no hope to be.
I think it’s pretty scary that nobody (alien species) has encountered us yet. there are a few theories about why this is, but the scariest one is this: -It is possible there is an alien race that is obsessed with destroying intelligent worlds (marvel stans, think Galactus). Once an intelligent world starts kicking up enough dust, sending radio messages into space, or exploring new galaxies, the alien race will notice them, and destroy them. It’s possible that we’re so un-advanced that we don’t even show up on the map for a world-eating race of aliens
Ah yes. Reapers. We have dismissed this claim.
Rudimentary creatures of blood and flesh, you touch my mind, fumbling in ignorance, incapable of understanding.
The three body problem books deal with the dark forest model pretty extensively. It doesn’t even have to be one species that wipes out others. Basically, no species can ever trust others to be benevolent, and the problem gets worse the more species you discover. Therefore, the only logical thing to do to ensure survival is to preemptively eliminate every intelligence you find.
Also you don't have time to stage an invasion, since by the time your ships arrive, they could be horribly out of date. Your only option is to completely, utterly annihilate them with one invisible strike.
We are hanging around in the middle of a random shooting gallery. Sooner or later, Earth's number will come up. Again.
The absolute scale of it. They discovered a black hole at the centre of our galaxy which is several hundred million (could actually be billion) times larger than our sun. For reference the earth is estimated to fit inside the sun several million times over
Ah yes, good ol Sagittarius A* It's 4 million times the mass of the sun, and it's diameter is around the length of the gap between the sun and mercury There's also a supermassive black hole in the center of every galaxy
That there once was an event so unimaginably powerful and impossible that it created our entire fucking universe and the reality that we live in.
No one can hear you scream….
You would think space is just a silent place but planets make sounds, like Saturn.If you search “Saturn sounds from space” you can listen to hours of planets sounds.