How unique is 'Earth-like' life in the universe?

Well thats the thing we really don't know if life "as we know it" here on Earth is an anomaly or common or anywhere inbetween. For all we know carbon based lifeforms that breathe some type of oxygen could be rare and most of the other life in the Universe lives in gas or ice giants. Or life like ours could be the norm and there may be a few anomalies out there who have evolved to life on places like Venus or something. We simply have no idea.

Technology is getting there but we still can't really see very many exoplanets in the grand scheme of things. One thing are able to conclude from the limited surveys we've done is that Earth-like planets are pretty common place in the galaxy. We see more gas and ice giants simply because they are much larger and easier to detect given the vast distances we are talking about here, but we've found our fair share of rocky worlds and plenty of rocky worlds in the "Goldilocks Zone" of their parent stars. We simply lack the technology to do much more than roughly analyze their atmospheres. We can't really see what's going on below them and if there are any lifeforms walking around down there.

Science can only speculate about what type of life there may be out there. We only know of one planet that can sustain life so we obviously look for planets that look like ours seeing how Earth is the only confirmed planet with life on it. The problem is that we could very well be looking right past plenty of planets with life on them that we simply don't pay much attention to because they aren't like ours. For all we know Jupiter and Saturn could be teeming with life floating around beneath the clouds. Or Europa could have a vast sea of life living in the ocean below the ice crust. Or Titan, etc.

As advanced as our technology is we are still basically in the stone age of space exploration. This is basically like primitive man walking around and wanting to find other life on Earth so he obviously walks around land looking for things that may look like him. He walks a few miles and doesn't see anyone so concludes that well his little group of people must be it. When in reality they live next to the ocean which contains 94% of all life on Earth but they dismiss it because since they can't live in there then they figure nothing else can either.

Even if we humans are only able to find one other planet confirmed with life then that would confirm that the Universe is full of life. Space is just ridiculously huge beyond what most human beings can even comprehend. We just simply do not have the ability to do much more than make bigger telescopes and peer out into the Universe. In order to find confirm life outside of our solar system it would require humans to send something down to one of these exoplanets and take a look. Given the distances involved in interstellar travel doing something like that is virtually improbable and almost impossible. Space is just way too big and seeing how we are fully aware that there is a cosmic speed limit even if we advance enough to take full advantage of that cosmic speed limit it still becomes improbable to send anything to visit another world.

So for all intents and purpose we are basically stuck on Earth and we aren't going anywhere for a LONG TIME, if ever. So unless we make a telescope powerful enough to see a huge alien starship or something orbiting another planet or they decide to come see us then we will likely never know if there is other life out there. The best we will likely ever be able to do especially in our lifetimes is to just keep finding Earth-like planets and speculating as to whether or not the conditions over there are right to support life like ours.

Our galaxy could very well be following the same timeline as Star Trek where there are hundreds of super advanced civilizations zooming around the galaxy and just ignoring Earth until we advance enough on our own to be worthy of talking to. Or there could be life on one of the planets around Alpha Centauri with telescopes pointing this way wondering if anybody lives over here on the little blue dot. Or we could be a freak of nature that somehow accidentally formed into self consciousness lifeforms sitting over here completely alone in our whole Universe.

We will very likely never know unfortunately....

 

Even when speaking in those terms the Universe is "likely" full of such organisms as well. Can we prove it? Likely not, likely never well, but the sheer size of the Universe and number of planets and stars makes it more improbable that we are alone rather than us being one of many.

I personally believe that we are one of countless developed lifeforms and our planet is one of billions that contains life. I believe that the distances involve in space just keep us too far away from one another with most of us sitting around wondering whether or not the others exist. I think even our own galaxy is full of life. If Earths human population was 1000 folks spread across the planet then there is a very good chance that you would go through your entire life without ever seeing any sort of indication that anybody else was here with you. When in reality you aren't really alone it's just that you live in Australia and your closest neighbor is in India but you don't even know India is there because when you stand on the shoreline you can't see it and it wouldn't matter anyway because even if you could see it you can't build a ship to get over there.

All of this is basically modern man reliving the same ideologies that our ancestors had. Thousands of years ago all humans living on Earth thought that their little part of the world was the whole world. Then technology advanced and they could explore more and find other people. Then once "civilized society" started up they figured that Europe, Africa, Asia was the whole world. Then low and behold one day they sail across the ocean into the void and accidentally bump into the other half of the planet that they didn't even know was there.

One thing that tends to hold true as humanity proceeds forward is that the more we learn and explore the more we realize that we were wrong. Thats the beauty of advancements in technology and science. The more science advances the more we tend to realize that things didn't quite work the way we thought they did. History has proven one thing for sure, the more humans try to see ourselves as something special in the Universe the more we realize we are wrong as time moves forward.

In the past few decades alone we went from once again thinking we were somehow unique to being slapped with the reality that holy crap there are other planets outside of our solar system. Then finding rocky ones, then finding Earth-like ones, then finding A LOT of them, then realizing that almost all stars have planets around them. That right there basically took away the last trump card that we humans had at thinking we were unique. For centuries we at least could hold on to the title of being the only Solar System with planets since we already lost the war on thinking Earth was the center of it. Now we don't even have that anymore. And the more we learn the more we will discover just how common the Earth is. It will just take time as other discoveries about our place in the Universe have taken.

 

Not really. Human's aren't even remotely close to being a Type 1 civilization. In order for us to "see" any other indications of advanced civilizations then they'd have to be at least a Type 2 and close enough to us for our telescopes to possibly see their Dyson Sphere or something similar to it. We wouldn't even be able to something as huge as the Death Star if it were orbiting around a planet in our closest interstellar neighboring star system.

The Fermi Paradox basically boils down to "If there are out there then where are they?" but such a conclusion is so radically unfounded that it makes almost no sense when dealing with the scale of the galaxy, let alone the entire Universe. The Universe is just too big, same analogy as comparing the Earth as the entire Milky Way galaxy and only putting a handful of people on it and our eyeballs are our telescopes. You could be living in a primitive community with stone tools and huts and the folks in NYC advanced enough to make NYC look like it does today but you still wouldn't know they were there because your eyes can't see that far and you live in Africa anyway.

In order for us to likely detect any other civilization they would have to have advanced beyond our own understanding of physics and what we even believe in physically possible. I'm pretty sure if starships were out there zipping around at Warp 9 then that would at least cause some sort of disturbance in space that we could detect somehow. But they would likely have to be passing by where we just so happen to have our instruments pointed. Which would be equivalent to picking out a single grain of sand in a sandcastle and stepping back and trying to hit it with a needle.

I think a lot of folks just feel that Earth is special and important because it is to us because we live here. And figure that well if other advanced life is our there then they would surely have made their presence known to us because we are Earth and we matter. When in reality there very well could be millions of other advanced Star Trek type civilizations zipping around all over the place and don't care about this little stone age planet one bit. We can't even send people past the moon after 40+ years of continued research. To an advanced civilization that can zip around at Warp 9 which is like a 1000x light speed then they might be looking at us the same way we humans with our iphones and computers look at an ant hill. Or other civs could be following a similar advancement path as us. Maybe some have colonized their entire star system which in itself is a great feat but still means virtually nothing in regards to interstellar space.

Just look at our own probes. Voyager finally left the Solar System which is a great human achievement. First thing humans ever created that actually left our Solar System, and it still works! Monument to human engineering! It took about 35 years which is a long time but that's manageable, still well within one human lifetime. Alright now lets alter it's course (if we could) and send to to Proxima Centauri, our closest neighboring star, that's the next great leap for us humans. How long will it take?

40,000 years....well damn.

 

Our magnetic field is the big one that saves us from having our upper atmosphere stripped away by solar radiation. We need that or else we'd be baked in UV radiation. We wouldn't be here without that so yes it is very important. Theia smacking into the Earth to create the Moon was necessary for life to evolve into it's current form.

However, we must also address the point of "current form". Evolution tends to well, evolve, based on the conditions present. Down here on the surface of Earth there is no threat of deadly UV radiation because we have an atmosphere to deflect it so life here didn't need to evolve to combat it. If we had no magnetic field to protect our upper atmosphere would be still be here and simply have taken a different evolutionary path that allowed us to deal with high exposure UV radiation? Maybe, maybe not. One thing Earth alone has shown us is that life evolves to adapt to the conditions present. Organisms living off of thermal vents in the deep oceans or over 2 miles underground evolved to survive in those conditions which are deadly to surface creatures. But life found a way to exist down there given the conditions present.

So whose to say that humanity wouldn't have simply evolved skin that could absorb the deadly UV radiation if it were present? Or evolved to breathe Methane instead of Oxygen if it were more present? There could very well be advanced life on other Earth-Like planets that may look like the Earth but doesn't have the nice magnetic field that we have to protect their planet from UV radiation. So they simply evolved to deal with it. Our lungs evolved to take advantage of the 21% oxygen levels in our atmosphere. Yes we breathe oxygen but only partially, if we breathe more than that consistently then it becomes toxic. So if the atmosphere had 50% oxygen then I'm pretty sure our bodies would have just evolved to adapt to breathing 50% oxygen and not simply have died off due to the toxic air.

Organisms evolve and adapt to the conditions present. When life began it didn't start off with a set of ideal requirements it would need to keep on surviving or else. It evolved to the conditions that were there. The first marine organisms to evolve into fish didn't evolve with lungs then all die off immediately with evolution going "whoops that didn't work".

So basically to answer your question unless we find an exact duplicate of Earth in all of it's features then we probably aren't going to find an exact duplicate of human beings or other Earth based creatures. Whatever we find (if we ever find anything) will have evolved to the conditions of their home world and would probably have about a 99.9999% chance of not being able to survive on Earth.

 

I'll agree that we may be able to reach Type 1 within the next 250 years if technology keeps advancing at this rate and we don't nuke ourselves to death first. But building a Dyson Sphere requires us to be a Type II civilization and I don't see us advancing nearly that quickly.

The folks in Star Trek are considered a Type II civilization and they supposedly live about 250 years in the future, so if we follow the same timeline as they do in fiction then we would be a Type II in 250 years.

At our current rate, no not likely without help. (Showing my inter nerd now), the only reason humans were able to advance that quickly in Star Trek was because they made a rudimentary warp drive that somehow worked about 46 years from now and the Vulcans saw it and decided to come talk to us lol. Now whether the Vulcans were helpful or harmful to our continued advancement is up for debate for Trek nerds. Either way, the humans in the Star Trek universe made some pretty serious leaps in advancement over a short period of time. They went from launching the first manned mission to Mars then 30 years later they have warp drives. 6 years later they managed to build an entire warp capable starship and send it off to colonize a planet 20 light years away.

As of right now we are technically on track for that. I'm pretty sure we will have humans on Mars by the time they did in Star Trek (about 2030), but in order for us to keep on advancing at the rate they did after that we'd need to discover something incredible that turns the world of physics as we know it upside down the way they did. 40 years from now I foresee humans having landed on Mars and likely even established a small colony. Perhaps launched a probe and lander to Europa and drilled through the ice to see what was down there. But I don't think we'll be able to build a fully functional warp capable United Star Ship in the next 55 years....

The Syfy TV show "The Expanse" takes place in the 2300's and seems way more likely and plausible to me in 300 years than Star Trek. I could see humans having colonized Mars and a few moons of Jupiter by then with space ships running around Solar System. I don't see us zipping around in the USS Enterprise at 1000x the speed of light in 300 years. I could be wrong though, we never know what tomorrow's discoveries may bring.

 

Yeah many sci-fi shows, movies, and novels usually conveniently dismiss the fact that other worlds are probably not suitable for human survival for the sake of the story. Star Trek loves doing this with the main characters always running around random planets without space suits and breathing just fine. In the Star Trek universe almost everywhere they go conveniently has the same atmospheric characteristics as Earth. That's the thing though, if/when humans do travel to our nearest Earth-like planet there is a 99.99% chance they won't be able to just land and start walking around perfectly fine. Our lungs evolved to breathe in an atmosphere containing mostly nitrogen, some oxygen, and a little bit of argon. Unless we conveniently find a planet with almost those exact same composite ratios then we are going to need a space suit.

Now could there be another planet with exactly the same makeup of 71% Nitrogen and 21% oxygen or at least close enough to where it wouldn't be deadly for us to breathe? Very possible. In fact there probably is. As you said the Universe is ridiculously huge, and many physicists believe that the Universe itself is actually infinite. So when talking about infinite then whatever can happen will happen or has happened. So in that case yes somewhere out there there is a planet exactly like ours down to the tee. But even just counting the Observable Universe there probably are a handful of planets that have a pretty similar atmospheric composition and magnetic field and unusually large Moon.

Time is fascinating and when it comes to whether or not another world could have evolved concurrently with Earth the answer is that we simply have no idea. We only one have one evolutionary timeline to study which is our own and without having any others for comparison we can't determine whether or not ours is slow, normal, or fast or somewhere in between. If our evolutionary time table is slow then there are possibly thousands of advanced civilizations zipping around the galaxy while we are sitting here struggling to get to our closest planetary neighbor. Thousands of whom could have come, evolved, and died off millions of years ago. Or if our timetable is fast then there could be thousands of civilizations in the galaxy who are just now discovering fire (if they had a planet sort of like ours). And if we are average and others are following the same path as we are then there could be thousands of other civilizations building huge telescopes and launching them into space and may have peered over in our direction and said "Wow we found another "Vulcan-Like" planet in the Goldilocks zone, I wonder if anything lives on that?" While we're staring back at them with Hubble and soon James Webb and wondering the same thing.

We've found quite a few pretty promising candidates so far and we haven't even remotely begun to scratch the surface of exoplanet research yet. We've found plenty in the goldilocks zone and have even been able to measure the atmospheric composition of some. And if life here on Earth (and Jurassic Park) has taught us anything, it's that life FINDS a way. I'm a betting man and after seeing some of these recent discoveries I'd be more than willing to bet that at least SOMETHING has figured out how to evolve on them, whether it's single celled organisms or full blown Klingon's I'm almost sure that there is something "alive" on at least one of these Earth like planets we've spotted so far.

 

I sure hope so that would be incredible. In order for that to happen though we'd have to come together more as a species rather than our individual nations I believe. One thing that almost all sci-fi fiction has in common is that "Earth" is almost always one and not a bunch of different warring nations. No single nation has the money to do this it would take a collective effort of most space faring nations to come together.

I won't be alive to see it launch for sure but even if I could just see humans start construction on some sort of star ship or colony ship that would be incredible. Hell I'm super excited counting down the days until James Webb launches next year which is going to show me fuzzy pixilated grainy images of tiny dots that are exoplanets. I'd jump up and down like a little kid if I saw NASA or SpaceX building a colony ship to fly people off to Ganymede or something.