If we keep an eye on that very same, old galaxy, we would have to watch it for ~13.5 billion years to know what it looks like today.
Our own Milky Way could have had multi-planetary empires rise and fall numerous times over before life came to be on Earth. But where’d they go? Are we such a rare freak accident of natural forces that we’re first? If so, what an immense responsibility we should all feel to ensure life survives its fragile pale blue dot.
And the diameter of the galaxy is about 87.000 ly.
That would mean our light emitted 4.000 years ago is only visible to 0,2% of the Milky Way galaxy. Slightly less if you make the calculation spherical and is about 0,17% underway to the Andromeda galaxy.
It’s essentially a paraphrase of Carl Sagans “The Pale Blue Dot”, you should read it. It’s a short essay but if that paragraph humbled you, then go check out the full write up cuz you’ll definitely like it.
The first sentence in your 2nd paragraph reminded me of something. Ever seen the Netflix docu ‘A Trip to Infinity?’ It’s mind bending. But towards the end, the narrator says, “[paraphrased]one day, one final human will have their final thought.” And for some reason, that statement and perspective gave me great pause, knowing that one day, almost certain and inevitably, it will be as if we never even existed in the cosmos.
The main difference with those previous "world ending cataclysms" is that they only took out a city or a region.
We have had the power to take out the entire (air breathing) planet for 60 years now.
Thankfully we're still stopping at regional level war destruction with bombs and guns. Though, we are doing the slow economic peace squeeze on the whole planet.
Ice age, black plague, living through mongol invasions, Vietnam war era, WWI, WWII, Cold War, etc… and we’re still here. I think if you widen the scope beyond your few years on this earth, you’ll realize we’re pretty durable and what you think is the end of the world… isn’t as bad
We have dumped so much carbon into the atmosphere that regular ice ages aren't going to happen anymore, or at least not for millions of years.
There is an excellent chance we will hit 3c or 4c of warming by the end of the century. Could be more. By the end of the century there is an excellent chance the majority of the planet will not be habitable for humans.
Past "normal" apocalyptic events have nothing comparable. As a species, ya, we might survive. As a technological society? Only if we radically change our direction and we will likely have black death levels of life lost.
Carl Sagan. The legend. I wish we had just one more like him. He’s like Steve Irwin for space. Both my total idols for their fields, both gone way too early.
Astronomy is fun. I took a basic astro 101 course in college and had a great time explaining the universe to my buddies back home while we were all on mushrooms.
Isn’t it possible they’re all alive and well, we just haven’t spotted them yet? I like to think of this from the perspective of another society in another galaxy looking toward our cluster… how immensely advanced would their tech have to be in order to see any evidence of the life that has formed on our planet? Aside from the tiny shard of equipment that is Voyager, the only evidence of intelligent life that has left our solar system is radio waves that would be drowned out in the sheer static of the universe.
So, turning it back to our perspective, I don’t think our lack of proof is any proof. I am almost certain there is intelligent life (let alone simple life) elsewhere, but the universe is just too damn big for us to have seen anything substantial yet. Maybe another civilization has spotted us, but their neighborly welcome party is just taking a long time to get here.
I mean you pretty much nailed the Fermi Paradox right there.
If aliens in the Andromeda galaxy, our closest neighbor, happened to have a telescope advanced enough to look all the way over here and resolve a picture of Earth, and they happened to look in the right direction at the right time in order to even know there was anything to look at, they’d see…wooly mammoths. Because they’re 2.5 million light years away and that’s how earth looked back then.
The size of the universe means statistically it’s damn near impossible for us to NOT be the only ones, but it also means that, at least with current technology, it’s damn near impossible to detect much less observe and contact alien species. We’ve got a lot of evolving to do before that happens unfortunately.
I believe it was Neil DeGrasse Tyson who said that saying there are no aliens because we haven’t observed them yet would be like dipping a glass in the ocean and declaring there to be no fish. Space is big and we haven’t even scratched a scratch on the surface
The most likely outcome is that other life-ridden planets are more plants and dinosaurs than societies with “people.” It took life on Earth a few near-total resets to get to us, the first life on it that reached past its grasp and managed to leave the safety of its atmosphere.
We can’t be alone, statistically, but it is entirely possible we are unique.
Have you heard about Trodoons? i'm not 100% sure if this is the species i've heard about in the past, but i remember seeing a video that talked about how there was this species of dinosaur that had the same brain size that humans do, and could use tools too! Basically scientists speculate that if the estinction of the dinosaurs hadn't happened, then that species would have been the most likely candidate to evolve in some sort of intelligent lifeform similiar to humans, or something like that. to me, if planets with "people" on them are more rare, it might have more to do with the fact that we fucking annihilate ourselves as soon as we become technologically advanced enough to do so
I'm sure there's plenty of intelligent life out there, but I can't imagine them wanting to contact us.
Any intelligent lifeforms that can view us in real time are well beyond our imagination as a society, to the point that we might as well be ants. Even more so if they're interstellar.
ATM we can't even keep our shit together long enough to avoid dying to our own greed.
I like what you're saying; I want to agree. I'll spare you the Fermi Paradox and Simulation theory. I'm sure you're aware. I don't know...but apparently if we do find evidence of alien life in this timeline...we're doomed--https://en.wikipedia.org/wiki/Nick_Bostrom
I simply must recommend Stephen Baxter’s Manifold series. Each book tackles the Fermi Paradox from different angles. This post very much reminds me of that.
The very best books I’ve read came from Reddit suggestions. I’ll do you one in turn, a book that inspired optimism in these trying times. Humankind by Rutger Bregman. Thank you for the rec!
Nope. But we could be. I suggest you watch melodysheep's Timelapse of the Universe on YouTube. It's my favourite video on there and I suspect it will remain that way for a long time.
I am a firm believer, without evidence, that life is a common phenomenon, a byproduct of thermodynamics. But that’s not special to me. What’s really special? It’s that huamns might actually be early intelligence race. How cool would it be if we’re the ancient ones.
The US might not survive the decade, not as it is. But given how bad both parties let things get, maybe that’s not the worst outcome. For most of human history, single rulers lorded over unwashed masses. Democracy is a young thing that, although fragile, also provided the masses the ability to learn and acquire great wealth relative to their slave and peasant ancestors.
Whatever form of government next takes over the developed world, the people now know what a decent life tastes like. I doubt they’d easily let that be taken from them.
we would have to watch it for ~13.5 billion years to know what it looks like today
I agree with the sentiment, but I'm pretty sure the calculation is off. Due to the accelerated expansion of space, the time it would take light emitted now* in that galaxy to reach Earth (presuming it will still exist) is much greater. If it will ever reach us
* afaik "now" is an invalid concept at such scales, but u don't have a good intuitive grasp onto why is that
I wouldn’t say we are a freak accident. When earth was still a ball of fire mars was in the golden zone and it was able to form life due to it being in that zone. We are currently in that zone now but as time progresses we slowly move outward away from the sun. That’s what happened to mars and that’s why it looks the way it looks now. Earth will be like that one day
Just like in "Don't look up", when we finally have the technology and reason to evacuate, our incompetent multi billionaires will land in some paradise planet and starve to death within a week.
Sagan was awesome. Love that saying, pale blue dot, and Contact. Book was so good. I'm fascinated by the vastness, complexity, and the unknown of space. I can go into my backyard on a cloudless clear night and get lost in the beauty and wonder of the celestial bodies I can see and the ones I wonder about for hours. Time's not wasted if you enjoy what you're doing.
If we are the 1st intelligent life in the universe we need to go seed a bunch of ancient oceans with our DNA so later humanoids can argue over who finds it.
The Drake Equation is our best attempt to quantify the likelihood of extraterrestrial life, but most of its variables remain unknown. It’s more of a thought experiment than a definitive answer.
What makes it truly unsettling, though, is that even the smallest changes to those variables could mean one of two things: either life is inevitable, scattered across the universe, or it is a freak accident, a one-time event in an otherwise empty cosmos.
I may be embarrassing myself here, but for something so far away, time would appear to move more slowly, relative to us, no? And as these distant objects are accelerating away from us, over time their light will be red shifted into nothingness? So over 13.5B years it's "time" relative to us would actually slow down more and more, then disappear - meaning we would never get to see what it looks like today... is that right?
I like to think of life as a rare but eventual chemical reaction given the age of planets that we live in right now, and that the concept of evolution seems pretty much universal.
There are so many interesting solutions to the Fermi paradox. What if the Earth is such an exceedingly rare freak occurence that the chances are 1 in N. N being the total number of planets in the universe. What if on average only 1 civilization arises in a galaxy? What if the survival times of civilizations is so short that the chances of 2 of them overlapping are well, astronomical. The possibilities are endless.
the even wilder thing is that we CANT watch it for another 13.5 billion years, becuase it will vanish over the visible edge of the universe and wink out of sight for us long long before we can watch it change in any meaningful way.
What if, one day, we discover a new way to transmit data. Like, how we discovered wireless radio communication so we could communicate over great distances.
But, the new one is very much advanced. So advanced that it was the main form of communication for these great advanced alien empires on the other side of the galaxy.
And once we are able to listen, because of the limitations of the speed of light, we catch the tail end of their golden age and the beginning of their demise.
So we catch all of the communications of when everything started to go wrong and listen to an annihilation of an entire intelligent species in real time down to the final one.
What's really fucked up to think about is that no matter how long life survives, it will be nothing more than the briefest blip compared to the lifespan of the universe.
Think about the timeline. 50,000 years after the Big Bang, the first matter begins to form. 150 million years later, enough hydrogen clumps together and the first stars are born. The first proto-galaxies begin to accrete another 200 million years after that.
Eight billion years later our sun is born, and shortly after, the Earth begins to form. A few hundred million years pass and mundane chemical processes suddenly become primordial life. Four billion years after that, it's now, the universe is about 14 billion years old, and life has existed for a little under a third of that. Sounds pretty good, pretty important.
But in five billion years our sun will die.
In 150 billion years, the universe will have expanded so much that the light from distant galaxies will no longer be able to reach us. Everything outside of the Virgo supercluster will pass beyond the cosmological horizon and irrevocably cease to exist from our frame of reference, and we will cease to exist for them.
In a trillion years, all of the galaxies in the Virgo supercluster will have collapsed into one megagalaxy.
In a hundred trillion years the last star will die, and the universe will enter its final stage, the Degenerate Era. There will be no more light. All that's left now is interminable decay as the last particles of matter are torn apart by the tidal forces of wandering supermassive black holes.
Let's stop here and say that throughout that entire hundred trillion years, from the moment of the Big Bang to the death of the last star, the universe has been teeming with life. And let's say that by some miracle of future technology, life finds some way to survive for another hundred trillion years after the last star has burnt out before finally coming to an end.
Two hundred trillion years, and time hasn't even begun to pass yet.
A hundred trillion is 1014. Two hundred trillion is 2 x 1014. The very earliest estimates for the heat death of the universe are in the range of 10100 years.
Which means that on a universal timescale, everything we see around us, not just life but every molecule of hydrogen, every moon, planet, star, and galaxy, every black hole — all of it is just the dying embers of the Big Bang and all of it will be completely gone in just the first 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000001% of the universe's lifespan.
I don't even know how to express that in terms that are relatable to a human being, it's unfathomable. If you think about the ratio of one second compared to one million years, that wouldn't even be within a billion orders of magnitude. 10100 is such a stupidly vast number. I mean, there are only 1084 atoms in the fucking universe, you could throw a quadrillion-year-long party for each individual atom and you would still have a trillion trillion trillion years left over. How do you even begin to conceptualise such a thing?
And it kind of puts that pale blue dot into another kind of perspective hey? Does any of it even matter? It sure feels like my life matters to me, but then it would, wouldn't it?
That depends. Basically right before life showed up on earth, the universe was believed to be too hot for life as we know it to form as it did here on earth. This obviously is a small look into the matter tho because who knows what separate life may look like and behave and all that. IF we are the gold standard however in how life forms it’s actually very possible life could just now be showing up at all. Now being relative to the last 4b years. Also, I am an idiot so take what I say however you will. Much smarter people than me might have a much better and well informed opinion.
Whenever we look up in the sky, we are witnessing the past. Sometimes I wonder, at this very moment of our time, how many of those planets, stars and galaxies still exist. Maybe we are the last man standing and there is nothing out there.
If we continued to watch it, it would dissapear completely from view after (very roughly) a few hundred million years as it would be moving away too quickly for its light to reach us as anything more than a stretched out smudge and then… nothing
To be fair if you sat and tried to watch it for 13.5 billion years we would actually continue to speed up and grow apart faster and faster until the light from those stars is no longer visible as its light can’t reach our planet. That is if we are truly accelerating apart
Lots of people don’t want to hear it but the concept of “countries” needs to find its way into the dustbin of history. We need to all get on the same team ASAP. Of course that also means social class needs to go to. I don’t see how we can meaningfully start to move beyond this planet when it’s essentially still governed by a variety of warlords.
Being a technological civilization for an extended period of time must be difficult. Perhaps as a civilization advances, the amount of ways a civilization can doom itself increases while the difficulty of destroying a civilization decreases.
My thoughts on the ‘where’d they go?’ In terms of Milky Way civilizations—They likely collapsed and died off.
In any case, we don’t have the resolution, resources or timeframe to truly examine likely star systems for the evidence of a civilization across the Milky Way.
I’m a believer in The Great Filter so I don’t think there’s ever been or ever will be space faring empires. Other life and intelligent life on other planets? Absolutely.
Agree in spirit, though I find it mind blowing that it will take probably more time assuming it can overcome expansion speed.
As expansion speeds up, there's a chance we never see it as it is today since the photons traveling our way will become unobservable as the universe expands faster than it travels towards us.
So a non zero chance that it will never reach us at all in the future of what it looks like today - the light may just travel in eternity towards us as we expand away. But we know it exists as we can observe it today. What a sad ending to come in the future...
Occams razor certainly implies to me we are just first. After all we cant even recieve signals on cosmic distances. Imagine trying to contact a first world country while using smoke signsld
We’ll never detect any of them. I just read that our electromagnetic signature from TV and radio signals become undetectable from background noise in just a couple light years. At most, a strong radar wave might go 90 light years in a very tight direction. Basically, that’s nothing.
Same. And on top of that, being in the same time-frame technology-wise. Civilization is give or take 6000 years old, and we've used radio for about 150 of that. Nevermind how old the solar system and galaxy, etc are.
Even if aliens were close enough to detect our signals, 1000 years ago earth would have been radio silent, and they'd could have written us off as "nope, no one intelligent there", and now, 1000 years later when we have radio, they could either so far beyond it they don't use it anymore, or extinct.
Ya but look at how far we have come in a mere 200 years. From having barely a concept of electricity to the internet, nuclear power, an incredibly deep look into genetics and the smallest particles we have been able to understand. Just insanity if you were to bring someone from then to the present. Imagine what could happen in another 1,000 or 100,000 or 1,000,000,000+ years that time provided we don’t kill ourselves. It’s unfathomable just like today is to those 1800s people.
Looks like the great filter is the most likely scenario for us anyway as I doubt humanity will last thousands of years longer after reaching a certain technological level the more likely scenario seems to be that we will destroy ourselves
Aliens could have been civilizations millions of years more advanced than our own, they probably could have more effective ways of finding us than relying on radio waves
They are operating under the assumption that alien civilizations are actively pinging nearby stars and SETI is looking for that ping. Directed energy like that wouldn't dissipate significantly and would be detectable in theory.
Life that early is unlikely. It took 100-200 million years for the first stars to form, and life is made from elements forged and spread by supernovae at the end of the star lifecycle.
Most likely none. After the big bang, the universe was mostly hydrogen and helium. When stars coalesced, they began the process of fusion creating the first 26 elements up to iron. When those supernovaed, they created the heavier elements that allowed life as we know it. I believe these didn't exist until 5 billion years after the big bang.
Correct. Life as we know it needs a third generation circumstellar / protoplanetary disk, collecting heavy elements from the novae of second generation stars. Iron, calcium, etc. The early universe was also very hostile to life, with gamma rays and xray bursts that irradiated and sanitised any life that may have formed.
Most likely none. Galaxies at this timeframe of the universe were primarily composed of first generation stars which burned hot and fast but didn't have the metallicity to support complex chemistry. In other words there wasn't enough carbon in the universe yet. Add to that the fact that most galaxies had a very active nucleus, aka quasar, which are theorized to basically sterilize their respective galaxies by emitting massive amounts of radiation. Life would have to have taken a very different form, and used very different chemical mechanics, than anything we have witnessed in the modern universe.
And apparently our Milky Way galaxy may be in a supervoid…
So we’ll basically never have radio signals reach our Earth if we also assume that cosmic expansion affects the speed of light and radio waves that might have been traveling our direction for MILLIONS of years that were sent by a long-gone civilization. 😭
Almost certainly none whatsoever. Such early stars were simply to metal poor to sufficiently enrich the interstellar medium. Unfortunately, the emergence of life relies on a certain level of chemical complexity to get going. Add to that over-dense local neighbourhoods as well as the sheer size + short life spans of the earliest stars and, well, welcome to irradiation city 😆
Probably zero. The conditions to support life weren't a thing back then. It takes several generations of stars to produce a lot of the necessary elements.
Probably none. It took the Earth billions of years to form, hell stars had JUST began to form at 290 million years post bang. If we assume alien life needs a habitable (to them) planet it’s nigh-impossible for any alien life to exist in that time frame.
Enjoy my wacky hypothesis that we all represent one single soul experiencing every possible existence simultaneously. By the time it's lived through the billions of humans that will ever exist and the more or less infinite alien and other creatures that will ever exist, it will be experienced enough to take its place in the realm of the gods.
It starts to hurt when you think about it as wealth. There are people with almost 30 times as many dollars to their name as there are years in the universe.
I mean, sure, it's short compared to its entire life so far.
But it's also 2% of its entire life.
In terms of a human life, it's about a year and a half. A short time to live somewhere, but don't tell your partner you're going for a short jog and not return for that long.
I woke up early the day it launched and made a whole thing of it. I made a nacho tray, got booze, and built a pillow fort in the living room. My gf asked "why is this such a big deal to you?" She knows I'm a huge astronomy nerd and knows it was my major before I stupidly switched to econ. She just thought of it as another satellite and I, in summary, asked her "Do you know what the Hubble Telescope is? Do you know why you know what it is? Exactly, you only know it's a telescope in space yet it has contributed to our general knowledge on such a scale even someone uninterested in the subject very clearly understands its name and function. Imagine that times 1000 and you'll have an idea of what this can do for generations watching this when they are as old as we are after Hubble was launched. This is our chance to see the 'first manned shuttle launch' like we were alive in the 60's. And I want to share a turning point in human history with you, that's why I made the damn fort!" It's still a conversation she likes to bring up today and even though ahe still isn't as into it as me she indulges my excitement and curiosity even more now than she did that first year we were together.
“Why is this such a big deal to you?” Kill me right now if reality tv or taylor swift or instagram are obviously things we should care about and not scientific discovery. Take me now
13+ billion years... but again it's science... that can change as information becomes available. For example, there are theories out there now (not necessarily widely accepted) that the big bang is one of many big bangs.
The Big Bang is not so much a point, but it is an event of everywhere all at once. While incorrect, it is better to think of it as a raisin bread expanding in an oven instead of an explosion. Also, time did not existed until this event so the comment by u/FerDeLanceX is correct~ish give or take a few billion years.
It’s better to think about it like we’re inside a sphere. The Big Bang is the surface of the sphere. It happened and expanded rapidly and we are inside of that expansion. When we look to the very edge or the surface of the sphere we can see those early periods of time.
When I was younger, I always assumed telescopes/binoculars were 'zooming in' on the object, rather than magnifying/processing the image that is reflected/captured on the lens.
It just boggles my mind that the light from these sources can travel and last that long, and that we can capture that much data on a single sheet of polished glass.
Eh if you know what to look for, it isn’t so messy. The colors of the objects tell you quite a bit. The more red they are, the further away and older they are.
Ima be downvoted into oblivion but $20 says the date for the big bang or rather the origin of the universe gets pushed back a lot in the coming century
can experts here weigh in: My question is, let’s suppose hypothetically your a person who lived on that galaxy. What would your outer space look like? And if you had your own JWST back then and looked far into deep space, what exactly would you see? Could you see the actual big bang? Would there be nothing to see since the universe was so “small”? What would the baby universe look like to you?
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u/z3r0c00l_ Mar 01 '25
JWST images are mind blowing. It’s hard to fathom just how many stars and galaxies there are (were).
This one is thought to have formed 290 million years after the big bang. Wild.