Science is good for anything. It’s for shattering the illusion that we have some kind of special or privileged place in the universe. As a great Carl Sagan once said, astronomy is a humbling and character-building experience.
We went from believing that the Sun and Moon and stars revolved around us to understanding that we’re, just one of several planets around one star, that’s, one of billions of stars in a galaxy that’s.
One of billions of galaxies, we went from believing that we’re separate from the animal kingdom and created in the likeness of an all-powerful deity, to understanding that we have a common ancestor with apes and descended from the muck and slime billions of years Ago we went from believing that our planet is some kind of special bastion for life, to understanding that we are just part of a teeming sea of life that spans the cosmos except wait.
We actually don’t know about that. Last part. In fact, we spent decades searching the Stars for any proof whatsoever that we’re, not alone, and so far we come up with zilch. No radio signals that and ambiguously prove that there’s alien life out there, no sign in the composition of the thousands of exoplanets that we found that indicate that there’s any life on them yet, but numbers don’T lie with billions upon billions of stars out there all with their own planetary systems.
The idea that we are the only planet in the entire universe, the holds life just flies. Against all logic, I mean: how is that possible? Could it be that we are right? All along is it possible that the conditions required to create life are so incredibly specific that this planet and the conditions that formed it are the only place in the entire universe that allows a life to survive, long enough to become intelligent.
This is the basis for the rare earth hypothesis. The article that I did on the Fermi paradox way back earlier on in this channel was the first big article that kind of took off and became something, and really, if that hadn’t been the case.
This channel, probably wouldn’t, be what it was today. It was a very random topic kind of channel back then, but after the Fermi paradox, article did well got a lot of sort of science. People coming along and asking questions, and it just kind of went that way.
So if it wasn’t for the topic of the Fermi paradox, this channel would not exist the way it does right. Now that’s, my way of making everything about me, the point is the Fermi. Paradox is a fascinating topic and if you’re, not up on that topic, you can watch my article from way back in my youtube channel here or just search YouTube for the millions of articles that are on this topic.
But here’s, just a quick refresher, so the Fermi paradox was credited to the physicist Enrico Fermi, who apparently, in a conversation about aliens, just asked a very simple question: where is everybody now we can see how vast the University of so many billions Of stars out there, the numbers are so ginormous that no matter how low the possibility of life springing up, like you did here on earth, no matter how small that percentage is that’s still a huge number of civilizations that should be bouncing around Out there, and yet we’re, seeing no proof of them whatsoever.
So why is that now there are a million different solutions to the Fermi paradox. Everything from super predators, hunting down other civilizations, to us being kept in a galactic Zoo by other aliens. But if you’re gon na get serious about the Fermi paradox, you have to consider what is really the most obvious answer to it, which is the reason why we’re, not seeing in the aliens out there is because they’re just not there when it comes to @ ro biology, we have a sample size of one and that’s.
Life on Earth. That’s. All we know there could be all kinds of life out there that doesn’t fit our definition of life whatsoever life that doesn’t depend on DNA or carbon or water. For that matter, all we can do is look at the life that sprang up here on the specific conditions of Earth life that began actually pretty fast in a few hundred million years as unicellular MUC, just self-replicating macroscopic organic machines, and it stayed this way for more Than two billion years before eukaryotes appeared, this means they developed organelles that did specialized functions like the nucleus.
In the mitochondria unicellular organisms became complex, just took 2 billion years. To get there 600 million years ago, multicellular life appeared 87 % of the time that life has been on this earth. It was simple one-celled organisms after 3.
9 billion years. It finally made that leap, but look what happened next. 540 million years ago, only 60 million years after multicellular life appeared, we hit the Cambrian explosion, hundreds of millions of different species swimming around in the oceans plants and animals just appeared on the scene out of nowhere.
Every plant and animal today can trace their evolution back to those creatures that popped up here. Okay, look at how fast that happened after four billion years of just sitting there doing nothing boom.
When people talk about the Greek filter, you have to consider the leap from unicellular to multicellular life as one of the great filters that life must go through. How rare is that? How stable must have planet B to sit there for four billion years before it makes that leap humans popped up here by the way? This question is prompt many, a scientists to consider what, if we are alone, what, if the conditions required to create intelligent life are so incredibly specific that it can only happen here and if so, what are those conditions? This was put forward in the year 2000 by Peter Ward and David Brownlee in their book rare earth why complex life is uncommon in the universe appropriately.
This has become known as the rare earth hypothesis, and these are some of the conditions that the rare earth hypothesis calls out our place in the Milky Way, and we’re all familiar with the Goldilocks zone.
The distance from a star that a planet has to be in order to have liquid water. We’ll talk about that more in a second, but there’s. Also, the possibility of a galactic Goldilocks zone – and we just happen to be in it Milky Way – is actually on the bigger side as galaxies go and for the longest time that was considered most likely.
That life would show up near the core of the Milky Way, because that’s, where all the action was the problem is this action produces massive amounts of radiation. Is this amazing article made of a Hubble photo of the Andromeda galaxy shows the center of galaxies are an absolute cauldron of massive stars and supernovas hyper Nova’s, gamma-ray bursts and yes, black holes.
All this activity throws around massive amounts of radiation. That might render planets in the vicinity sterile. At the very least, you can say goodbye to having at night if you live there, whereas we are no, we’re near the core and actually in between two spiral, arms.
This places us far away enough from the chaos of the star factories and the spiral arms, but close enough to take advantage of all the heavy elements that get blasted out of supernovas next door plus being in the location where the lower density of stars provides a Lot fewer opportunities for a star to swing by and have its gravity muck up all of our orbits.
Could it be that we’re nestled into a nice little Goldilocks zone in our galaxy? Because if that is required, that rules out the vast majority of stars in our galaxy, our Sun type? Our Sun is categorized as a g2 main sequence star, which means it remains very stable for a very long period of time.
It’s also possible this just the right size and temperature for life. Larger hotter stars would also have habitable zones, but they also put out a whole lot more ultraviolet radiation, which would ionize the atmosphere and smaller red dwarf stars require their planets to orbit so close that they become tidally locked, which is not very good for life.
But even stars exactly like our Sun have a limiting time factor earlier on in the star’s, development, it’s, a lot more volatile, it varies in luminosity and intensity and then it smooths out for a long time before it eventually Goes red giant and collapses, so it’s in that middle period.
That’s, the sweet spot for life now. Luckily, that’s several billion years, but still once you eliminate all the stars in the really active regions of the galaxies. And then you eliminate stars that aren’t like our Sun and then you eliminate the stars that are too young or too old to be likely to have life.
You’re, getting rid of the vast majority of stars and we’re just getting started our distance from the Sun. Once you & # 39. Ve got your hands on the right kind of star. You & # 39. Ve got to have the right kind of planet in the right kind of distance from the star.
That means a rocky planet in the habitable zone. Now our solar system is set up with four rocky inner planets and four outer gas giants, and we thought that this was normal. I mean it makes sense, Rock is denser, so you would imagine it would gravitate toward the center of the the solar system and then the gas giants would form further out.
So we expected to be seeing that as we started finding exoplanets out there in the universe, we thought we would see this same pattern. Nope, a team led by Lauren Weiss at the University of Montreal studied 355 stars that contain 909 planets using data from the Kepler space telescope and what they found was that actually, in most of these cases, the planets were roughly the same size and very evenly spread Out, whereas in our solar system, we got everything from mercury, that’s, the size of our moon to Jupiter.
That’s a thousand times bigger than Earth and Saturn is as far away from Jupiter as Jupiter is from the Sun and Uranus is as far away from Saturn as Saturn is from the Sun. It almost gets exponentially further away the further you go.
This extreme variation in size and distance makes our solar system kind of the oddball it turns out, and it’s. Making us really have to rethink how our solar system was formed and why it’s, so much different from all the others that we’re, seeing out there.
In fact, judging by the planetary model, we’re, seeing around other stars. It’s almost like we have two different solar systems going on the inner and the outer solar system, and then in the inner solar system.
We have one planet. Us that just happens to be in the habitable zone, but could the fact that we have this unique configuration of planets be one of the factors that created life here on earth? Maybe so we have Jupiter space is a shooting gallery of asteroids and comets and as we’re, finding out interstellar objects, any of which could have slammed into Earth and disrupted this all-important stability required for life to form.
Thankfully, we & # 39, ve got Jupiter out there being all big and sucking up all these objects like a big interplanetary Roomba in 1994, Comet shoemaker-levy 9 slammed into Jupiter, and we actually got to watch this in a real-time with the Hubble Space Telescope.
It was one of the most amazing things I’ve ever seen. We never seen anything like this before and it left scars on Jupiter the size of Planet Earth and another impact site showed up again in 2009, so this vacuum cleaner phenomenon, is real.
In fact, some studies have shown that Jupiter gets hit by comets and asteroids 2,000 to 8,000 times more than the earth does, and if it wasn’t for it being out there, we would be bombarded with this stuff all the time that asteroid that Wiped out the dinosaurs turns out would be just like a pretty common event, and life would have been set back over and over and over again and again, while Jupiter is the biggest that’s, just one of four gas giants out there that are Sucking up a lot of these objects, so we have multiple layers of protection here, our moon.
So, ironically, while we have benefited from these, you know bouncers of the solar system preventing impacts from hitting our earth. It turns out that the biggest impact that ever occurred on Earth may have been the best thing that ever happened to us.
I’m, talking, of course about the impact that formed our moon. I won’t, spend too much time on this, because I’ve already covered this in a previous article. You can watch it here down description, but it turns out that our moon is very unique in the solar system and may play a huge part in why life was able to arise on this planet.
It stabilized our rotation and brought about tides, which it turns out. May have played a huge part in life forming because it’s, thought that tide pools that evaporated and concentrated organic compounds, or we’re.
The first replicating cells came from, but the question for this article is: how rare is this phenomenon and all we can say, is we don’t, see anything else like it in our solar system? Now there are moons around Jupiter and Saturn that are bigger than our Moon, but in terms of the ratio and the size between the planet and the moon, there’s.
Nothing else like it that we’ve seen Mars is the only other rocky planet that has moons and those are really more like captured, asteroids and before anybody says anything about Pluto and Charon. Those are really more like two dwarf planets.
That sort of found each other and rotate around each other. This is such an unusual situation that the only thing that we can think of that would have caused. This would be a mars-sized proto planet hitting a glancing blow on our planet and peeling away and in forming a moon.
In that way, a theory that has been backed up by evidence of moon rocks and if that’s, the case just think about how perfect this angle had to be in order to get it to create this moon. If they’d have been any steeper, it may have blown the planet, all the bits or it could have just gotten sunken in and created one gigantic planet, either way it’s, something we’ve only seen happen in Our solar system once and it’s still kind of early to be able to tell if we could find something like that around other stars.
We’ve only found one EXO moon last October and it was a neptune-sized moon, orbiting, a jupiter-sized planet. Okay, there’s. A few more things I’m gon na go through here. I’m gon na go through them really quickly strong magnetic fields we’re, the only rocky planet in our solar system that has a strong magnetic field produced by an internal dynamo of liquid and solid iron, nickel alloy spheres in the Core of our earth and this strong magnetic field plays a huge part in protecting a life on the planet, our strong magnetic fields, more common in rocky planets around other stars.
We have no way of knowing right now, but judging from our own solar system, there’s, no reason to think that they would be tectonic plates. We’re, also, the only planet with tectonic plate activity and most rocky planets and moons have at least a layer of liquid rock underneath the surface.
But earth is the only one that has these tectonic plates with fissures that allow for superheated gas to escape into the atmosphere and thicken up the atmosphere enough to support life Mars. For example, doesn’t have tectonic plates, but it does have magma under the surface.
So when it comes up it, just kind of like comes up in one spot over and over again over billions of years. Do you want an olympus mons, because that’s, how you get in olympus mons, but here on earth? The crust is in this constant state of renewal, getting sublimated underneath and melting down, taking with it all of its organic molecules from the life up on the surface.
This gets melted in to the crust that comes back up through those fissures and it’s, thought that this kind of helps remineralize and make that land more fertile and easier to grow life life that changed the atmosphere as plants took in you know, Carbon dioxide and nitrogen turned it into oxygen.
Animals did the same thing in Reverse, but earlier on in the life cycle of our planet, it was totally different. The earliest Earth had a toxic atmosphere of methane, sulfur, ammonia, carbon monoxide and even hydrochloric acid, not exactly a kind of place.
You’d, want to go on vacation, but it might be just the right mix of ingredients for life to form, and this specific group of ingredients might be exceedingly rare amongst planets. The point is a lot of very specific things had to happen for intelligent life to form on this planet, things that have been around from the beginning and it’s.
All we’ve ever known, so we think it’s normal. We think it’s common, but the more we look around out there. We’re starting to realize it’s, actually not normal, and it’s actually quite uncommon. In fact, it might be so infinitely unique that these specific conditions might not exist anywhere else in the universe and that we are completely and utterly alone.
It’s, a sobering thought, but we & # 39. Ve got no proof otherwise. Now it needs to be said. Not everybody is quite such a debbie downer. On this. There are a lot of people that refute the rare earth hypothesis, one of those things that they say is that it’s.
A very human centric. Look at life. You know, as I mentioned earlier, we have a sample size of one and we’re looking for places that creates the kind of life that we know, but there might be all kinds of life out there that’s completely counter to Our knowledge and understanding, in fact we live on such an oddball planet.
Maybe we’re, the oddball species in the universe. You know, maybe they stumbled upon us and we’re like okay. What is that and fundamentally for many people? Just goes back to that numbers thing. You know there’s, just such an unimaginably huge number of stars out there in the universe that the possibility that we’re alone is just well impossible.
Let’s. Go back to that end drama to a picture for just a second. Every dot in this image is a star a star with possibly multiple planets around it. Is it really possible that none of these stars have rocky planets with atmospheres that not one of these stars have planets with a large, stable moon in the Goldilocks zone, then not one of these planets have tectonic activity or magnetic shield? Is it really possible that not one of these millions of stars in this one corner of this one galaxy develop the way ours did with a large gas giant surrounding a ring of rocky planets? Is it really possible that the Venn diagram of chemicals necessary for life and conditions necessary for life never touch in any of these stars? I think it’s, naive to think that life could have never possibly formed in all this vastness, but that doesn’t mean, I think the universe is teeming with intelligent life.
Intelligent life has only existed for a blink of an eye in cosmic history of our planet. It took 4.6 billion years to get here and there’s, no guarantee that we’re gon na last, the extra billion years that the Sun is gon na, be able to support life on this planet before it gets too hot.
It makes it impossible to live here anymore. In fact, depending on who you ask, we’re doing our damnedest to end this thing as fast as we possibly can. So it is possible that millions of stars have been able to create intelligent life throughout their life cycles, but those life-forms didn’t make it and you can go down the rabbit hole.
The great filter here to explain that, but you don’t have to stars, die and maybe interstellar travel, just isn’t possible. Maybe the the distances are just too vast. Maybe the history of our galaxy and the universe as a whole is just a series of explosions of life popping up like twinkling Christmas tree lights, no, two ever popping up at the same time.
This is why it would be the most amazing discovery in all of history if we were able to find microbes somewhere else in our solar system, we were able to dig underneath the ice of Europa and find little you rope in bacteria swimming around.
That would completely make us rethink everything we know about life. If life could spring up twice in one solar system, the possibility of us not being goes up exponentially, but until that happens, let’s do our best to treat this planet like the rare and precious jewel that it is.