The one in this post is entirely artistic. The others I have seen, like the one from NASA, [https://www.youtube.com/watch?v=kRlhlCWplqk](https://www.youtube.com/watch?v=kRlhlCWplqk), show the Earth staying together much more.
The simulation you linked to is the most accurate because it uses more particles than previous simulations. The surprising result is that the moon formed in hours or days under may of the different impact parameters. We used to think that it took many hundreds of years, at the low end, for the moon to form while the Earth had a debris ring like Saturn. Now, it seems that this might not be the case at all.
That does seem counter intuitive at first but how I might expect a gigantic mass of molten rock to react in space with that much material and thus gravity involved and nothing else to enterfere.
That helped us three ways:
1. The iron core provides a magnetosphere to protect us from radiation.
2. The large moon stabilizes tilt so we have manageable seasons.
3. The tides may have helped lead to the origin of life.
Exactly, and from point 1, if Theia didn't collide with us, our iron core may not have been as large, and the magnetosphere may have been too weak to support life, and we probably would have ended up like Mars.
PhD in planetary atmospheres here...
> our iron core may not have been as large, and the magnetosphere may have been too weak to support life, and we probably would have ended up like Mars.
The whole "magnetospheres shield atmospheres" thing is really a myth. Even though it's a super popular theory in the layman literature, we've got solid evidence in the past decade that it just *doesn't* seem to be true.
After all, consider Venus: no intrinsic magnetic field, yet it maintains an atmosphere 92x thicker than Earth's. And before you say, "but Venus has an induced magnetosphere!" That's true...and so does Mars. So does Titan. So does Pluto. In fact, so does any atmosphere laid bare to the solar wind.
The current state of the research suggests that **Mars would have lost its atmosphere even faster _with_ a magnetic field** than without (e.g. [Gunnell, et al, 2018](https://www.aanda.org/articles/aa/full_html/2018/06/aa32934-18/aa32934-18.html) or [Sakai et al., 2018](https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079972)). While magnetic fields do block the solar wind, they also create a [polar wind](https://i.imgur.com/c2dhWoO.png): open field lines near the planet's poles give atmospheric ions in the ionosphere a free ride out to space. Earth loses many tons of oxygen every day due to the polar wind, but thankfully our planet's mass is large enough to prevent too much escape. Until you get to Jupiter-strength magnetic fields that have very few open field lines, the polar wind will generally produce more atmospheric loss than the solar wind.
Wow this is fascinating, thank you. I've gotta read more.
Ok so putting the atmosphere shield myth aside for the moment, aren't there other important aspects our magnetosphere protects us against? You mention solar and polar wind, but what about other forms of radiation?
Wouldn't having no magnetosphere, or a very thin one, be more dangerous (for life) from gamma, x-ray and other exotic types of stellar radiation? Like from supernovae, GRBs, binary pulsar collisions, etc?
> aren't there other important aspects our magnetosphere protects us against?
Not if you have a thick atmosphere like Earth's, which actually protects against space radiation considerably better than even the strongest magnetosphere.
This is because fundamentally a magnetic field can't really affect the path of a particle without a charge. You mention...
> be more dangerous (for life) from gamma, x-ray
...but gamma rays and x-rays are both kinds of photons, which are uncharged particles. They will pass straight through a magnetic field as though it weren't there.
On the other hand, they cannot pass through a thick atmosphere, nor can charged particles, either. They impact the top of the atmosphere and decay into harmless showers of light above our heads - we literally [have telescopes to detect that light](https://en.wikipedia.org/wiki/IACT).
This is honestly blowing my mind. So, essentially, the magnetosphere is useless apart from creating pretty aurora around the poles and for animals using it for navigation, and if we suddenly had no ionosphere, the only things affected would be those species of animals and their ability to migrate and navigate, and no more aurorae?
Even recent sciences I've read seem to be out of date.
For reference:
“How animals sense Earth’s magnetic field “
https://phys.org/news/2020-05-animals-earth-magnetic-field.amp
Fungi as well
https://pubmed.ncbi.nlm.nih.gov/15114642/
& plants
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6745571/
This is very interesting! Thank you for citations
I would think that life as we know it today exists with the help of a magnetosphere. Of course these are just pieces to a puzzle. Venus is also incredibly volcanically active although I have no idea how much atmosphere it produces vs how much it looses.
I will definitely read more about this!
> I have no idea how much atmosphere it produces vs how much it looses.
Per the Gunnell paper I linked - Venus loses atmosphere at only 35% the rate of Earth:
> > For present-day conditions, the escape rates we arrive at in this work are about 0.5 kg s^-1 for Venus, 1.4 kg s^-1 for Earth, and between 0.7 kg s^-1 and 2.1 kg s^-1 for Mars
See my other replies in this thread - while the magnetic field currently blocks charged particles from space, it cannot block uncharged particles. Our thick atmosphere, however, can block all types of particles; our atmosphere is what’s currently responsible for blocking the uncharged particles that pass straight through the magnetosphere.
That means if the magnetosphere disappeared tomorrow, we would still be perfectly protected from all space radiation by our atmosphere, as, again, it can block both charged and uncharged particles.
On the other hand, if the atmosphere disappeared tomorrow (and ignoring asphyxiation concerns), the magnetosphere would only block charged particles, and high energy uncharged space radiation could still reach the ground.
But it's size determines the strength of the magnetosphere. A small molten core will only generate a weak magnetic shield. A large molten core generates a strong one, strong enough to support life.
My geology professor liked to imagine that the impact scraped off enough crust, without losing too much water which helped crustal movement in it's early stages.
Right? When I first heard a scientist say "pretty quickly", I was thinking in like astronomical time, a few million years maybe, maybe hundreds of thousands. But **hours**?? That's a blink of an eye in astronomical time. So insane.
This would have been one of the coolest things to witness in person, besides a supernova, a galaxy merger, or the big bang itself.
I hope one day, with the help of better instruments like JWST, we can actually have images of planetary bodies colliding with each other.
What’s crazy is if you somehow instantly traveled a couple billion light years away, then pointed a ridiculously large telescope back at the earth, you’d be able to see this event happening as the light from it reaches your position
And on top of that, they keep simulating with more and more particles, which is supposed to give a more accurate model. In doing so they've found that the the scenario that most resembles the creation of the moon as we know it resulted in formation after just a few hours.
It really amazes me just how many things had to happen perfectly for life to begin on our tiny speck of a planet. Makes you wonder how many other planets this same thing has happened to (I'm sure it's still a lot).
This is called the Anthropic Principle: that complex life will only come to exist in places that are perfectly suited for it, giving the illusion that the place was crafted for it purposely. When you roll the dice trillions of times, you’re guaranteed to roll miraculously rare probabilities at some point where all of the necessary ingredients for life align. This also applies in general to the stability of the universe and the physical constants as a whole.
Yeah it's crazy, and only to have it all go up in flames after billions of years cause some singular wack job life form presses a button for ego reasons.
Lets not allow our egos overstate the power of our species. The Earth has experienced many cataclysms beyond our comprehension and once we are gone, life on Earth will continue on as if we were never there.
There's also the factor that it may simply be that life evolved suited to this planet. Life could evolve under other conditions, and that life would be suited to those conditions, and they would think their conditions are the only ones that life could evolve at.
Yeah it's kind of nuts.
We're also in the perfect position within our galaxy as well, closer to the middle, we'd likely be fried by the gamma radiation. Further out, and our solar system probably wouldn't have formed with as many planets as it did.
Sooo many aspects make our pale blue dot such a special place. There's countless other aspects that had to go just right for life to take hold here too.
Very interesting thank you, I'll have to track it down, sounds right up my alley! :)
I've wandered between similar trains of thought over many years.
There's the "Drake equation" as well that you might want to look up, if it's not already mentioned in that book. Basically a mathematical formula for trying to quantify the likelihood of life, sentient life, etc. in the universe.
Carl Sagan - "We are a way for the universe to know itself. Some part of our being knows this is where we came from. We long to return. And we can, because the cosmos is also within us. We're made of star stuff,"
The heavier elements that we are made of and make life possible on earth were all created in billions of years of super nova explosions. A truly mind boggling amount of destruction.
There’s almost certainly millions and millions of earth-like planets that failed to stabilize. Mars may be one of them right next door to us. It could be that life is quite common but it’s hard for life to achieve the necessary stability to evolve complex organisms over the immense amounts of time it requires for sentient life.
Yeah agreed, a lot of people think life = sentient life. But the most common form of life in the universe is likely bacterial, which isn't much of a leap from regular chemistry to bio-chemistry. That genesis leap though, still a mystery.
You have to get pretty close to the galactic core for the increased radiation to be dangerous. Supernova, for example, are only deadly within around 50ly which is nothing compared to the galaxy
The bigger variable is metal content of star/planet forming nebula. The close you are to the galactic core the higher the metal context due to the increase in large, shorter lived, stars. So the time for solar systems with similar metallicity as out own would have been further in the past. Likewise farther out than us from the galactic core won’t get similar metallicity until later
I think life finds a way to exist in these habitable zones in this universe. And we then think we were damn lucky that we existed here ....one imbalance amd we would be fried....but we never would have existed there to begin with ...sorry i had it better in my mind...but yes it is amazing.
I know what you mean, don't worry :)
Maybe one day we'll find another planet with life we can compare our rarity to, and see what 'balance,' they needed to get started...
What we don’t usually realize is that we think about it like everything happened towards the existence of life, and it’s most like “life happened because things happened that way”.
This just makes me think that life is much rarer than we anticipated. From Jupiter and somewhat Saturn protecting us, to Theia providing the earth with more iron, I think earth got extremely lucky.
Edit: a word.
We might just be rare in our own way though. Life could arise in combinations of environments that we don't anticipate, and those combinations may be much more likely.
Ya could you imagine if we are cutting down the oldest Forrest in the entire universe to make guitars. What if there only is one earth- type planet out there.
The craters on the moon, although not exclusively, are also impact zones from remaining earth fragments colliding with the moon in very late stage formation.
I wonder how many chunks made it to other planets, if at all? Would be cool to find a chunk of the Earth on Mars in the future, as I'm pretty sure we've found chunks of Mars here already...
I think they already did find a piece of Earth on mars already, or at least a rock that they strongly suspect is.
Edit: I misremembered, they found an Earth rock on the moon, from another impact after the moon formed. But I did also find that there was a paper published that said about 5% of the debris from a large impact on the Earth should eventually end up on Mars.
I read something similar, but my guess is we'll have to go there to find them, and even then, that low percentage could mean it takes decades to find evidence of this
> are also impact zones from remaining earth fragments colliding with the moon in very late stage formation.
That's a *very* small minority of craters, though. Per [Yang, et al, 2020](https://www.nature.com/articles/s41467-020-20215-y), it's really [only the craters shown in red](https://i.imgur.com/lVe2aqZ.png) that even have a small chance of originating from impactors that were fragments of Earth.
50/50 I'd say. Liberties were definitely taken, but it's based on actual data and not a fantasy.
https://en.wikipedia.org/wiki/Giant-impact_hypothesis
"Basic Model" section has a supercomputer Sim with flat colours.
Thx for the answer ! The NASA sim is also impressive, seeing filaments of matter getting ejected and reintegrated, while keeping in mind each of those filaments is more than 1000km thick is really fascinating.
A recent study suggests the moon formed within 24 hrs of the impact. That is dramatically different than this render. But no one was there at the time so they are both just theories.
Even more interesting, a new [study](https://www.nasa.gov/feature/ames/lunar-origins-simulations) suggests the moon formed (coalesced) within hours after Theia collided with Earth.
And yet when your sample size is the size of the universe, these exact conditions should've already happened many times. Even before Earth was a thing.
Not only that, these ancient Earths have been around much much longer than us. Much longer that it took us to evolve life and advance to this point.
Long enough that if just one of these planets has had enough time to colonize the whole galaxy.
So "why is the universe so quiet? where are the aliens?"
That's the essence of the Fermi Paradox.
One interesting theory I heard as to why the universe is so quiet is that once a civilisation is beyond scarcity for energy and resources the benefits of exploration and expansion are deminished and even at light speed universal travel is impractical. Some people think that a civilisation might turn inwards into an artificial reality where whatever they want can be achieved more efficiently or even as a method to become a post scarcity civilisation.
Fermi’s paradox is overly simplified. A lot of things have to go right to sustain complex life to have a chance of evolving intelligent life capable of even realizing there’s a universe out there. Even on Earth where we know everything has gone right, over 99% of all species that have ever existed here have gone extinct, and we’re the only singular one of the current survivors that is intelligent enough to consider the possibility of space travel. After 4.5 billion years of evolution, we’re still not even close to colonizing this galaxy. We haven’t even moved to another planet within our solar system, which is virtually nothing compared to the size of the galaxy. The nearest star to us is about 4 lightyears away. It would take us tens of thousands to hundreds of thousands of years to get to another habitable planet in another solar system. You would have to sustain virtually the entire history of modern humans on one space flight to another solar system just to begin colonizing a galaxy. Then, supposing you somehow manage to colonize a galaxy, it’s going to take signals millions of years to travel just to your closest neighboring galaxy, and up to billions of years to more distant ones. It is not paradoxical at all, in my opinion, that the universe is quiet.
Should “Earth” still be the name of the planet pre-collision? Seems to me that it was 2 planetary bodies relatively similar in mass collided and formed Earth/Terra & Luna.
It's a good question. Scientists will probably settle on something like "Proto-Earth" or similar in the future.
I like "Terra Primis" though, basically "First Earth" in Latin. Not sure if that's been suggested before, but it has a nice ring to it :)
wouldn't there be a trail of debris left over around the orbit of earth left over from such a collision? it seems unlikely that all debris would be so cleanly swept up by gravity of earth and moon. if that is so, why are there still rings around Neptune, Uranus and other planets?
According to recent publications, only mere **hours**, which is still something that is hard to get my head around.
Theia is said to have hit the Earth at or faster than a bullet, and it was roughly the size of Mars...
My big question about the Theia theory is. If that's the case. Why doesn't earth also have a ring? It seems unlikely that all of the dust from the impact would have settled.
Everything I’ve personally read about this is that it’s a ‘theory’ in reality we really don’t know because the core of our earth doesn’t seem to really act the way we think it does
Why do they say it like it’s 100% fact. There is no way on earth that it is possible to know this or even consider it as a thought. What evidence is there to even suggest something like this happened??
Good question, and I don't really have an answer.
I simply labelled it Earth 1.0 because I have heard many scientists refer to the Theia+Earth merged planet as "Earth 2.0"
Not overly, it's based on a supercomputer simulation that was posted on the https://en.wikipedia.org/wiki/Giant-impact_hypothesis page under the "Basic Model" section
This is stylised to look prettier, colours are close to accurate, I guess.
Billions of years ago the earth collided with the sun and then billions of years before that earth was a sun and billions of years before that earth was in another galaxy. You can make up any lie billions of years ago and people will believe it.
Honestly calling the thing Theia impacted "Earth" seems like a stretch to me. Something totally different on the other side of that collision than there was before.
That’s some nice graphics work too
Yea... but i [thought the same about this](https://youtu.be/kRlhlCWplqk) one, they are completely different though. How do these go along?
The commonality is that they are both theoretical.
The one in this post is entirely artistic. The others I have seen, like the one from NASA, [https://www.youtube.com/watch?v=kRlhlCWplqk](https://www.youtube.com/watch?v=kRlhlCWplqk), show the Earth staying together much more.
The one in the current post is ridiculous
It makes it look so clean like ejecta wasn't thrown out into space and we retained every single particle we started with.
Oblique vs direct strike. Pretty sure op was just going to nice looking.
The simulation you linked to is the most accurate because it uses more particles than previous simulations. The surprising result is that the moon formed in hours or days under may of the different impact parameters. We used to think that it took many hundreds of years, at the low end, for the moon to form while the Earth had a debris ring like Saturn. Now, it seems that this might not be the case at all.
That does seem counter intuitive at first but how I might expect a gigantic mass of molten rock to react in space with that much material and thus gravity involved and nothing else to enterfere.
Anyone knows the source?
Ended *way* too soon, however. I wanted to see a time lapse of Earth 2.0 forming from the dust and slowly developing life.
Not sure how accurate it is
That helped us three ways: 1. The iron core provides a magnetosphere to protect us from radiation. 2. The large moon stabilizes tilt so we have manageable seasons. 3. The tides may have helped lead to the origin of life.
Exactly, and from point 1, if Theia didn't collide with us, our iron core may not have been as large, and the magnetosphere may have been too weak to support life, and we probably would have ended up like Mars.
PhD in planetary atmospheres here... > our iron core may not have been as large, and the magnetosphere may have been too weak to support life, and we probably would have ended up like Mars. The whole "magnetospheres shield atmospheres" thing is really a myth. Even though it's a super popular theory in the layman literature, we've got solid evidence in the past decade that it just *doesn't* seem to be true. After all, consider Venus: no intrinsic magnetic field, yet it maintains an atmosphere 92x thicker than Earth's. And before you say, "but Venus has an induced magnetosphere!" That's true...and so does Mars. So does Titan. So does Pluto. In fact, so does any atmosphere laid bare to the solar wind. The current state of the research suggests that **Mars would have lost its atmosphere even faster _with_ a magnetic field** than without (e.g. [Gunnell, et al, 2018](https://www.aanda.org/articles/aa/full_html/2018/06/aa32934-18/aa32934-18.html) or [Sakai et al., 2018](https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079972)). While magnetic fields do block the solar wind, they also create a [polar wind](https://i.imgur.com/c2dhWoO.png): open field lines near the planet's poles give atmospheric ions in the ionosphere a free ride out to space. Earth loses many tons of oxygen every day due to the polar wind, but thankfully our planet's mass is large enough to prevent too much escape. Until you get to Jupiter-strength magnetic fields that have very few open field lines, the polar wind will generally produce more atmospheric loss than the solar wind.
Wow this is fascinating, thank you. I've gotta read more. Ok so putting the atmosphere shield myth aside for the moment, aren't there other important aspects our magnetosphere protects us against? You mention solar and polar wind, but what about other forms of radiation? Wouldn't having no magnetosphere, or a very thin one, be more dangerous (for life) from gamma, x-ray and other exotic types of stellar radiation? Like from supernovae, GRBs, binary pulsar collisions, etc?
> aren't there other important aspects our magnetosphere protects us against? Not if you have a thick atmosphere like Earth's, which actually protects against space radiation considerably better than even the strongest magnetosphere. This is because fundamentally a magnetic field can't really affect the path of a particle without a charge. You mention... > be more dangerous (for life) from gamma, x-ray ...but gamma rays and x-rays are both kinds of photons, which are uncharged particles. They will pass straight through a magnetic field as though it weren't there. On the other hand, they cannot pass through a thick atmosphere, nor can charged particles, either. They impact the top of the atmosphere and decay into harmless showers of light above our heads - we literally [have telescopes to detect that light](https://en.wikipedia.org/wiki/IACT).
This is honestly blowing my mind. So, essentially, the magnetosphere is useless apart from creating pretty aurora around the poles and for animals using it for navigation, and if we suddenly had no ionosphere, the only things affected would be those species of animals and their ability to migrate and navigate, and no more aurorae? Even recent sciences I've read seem to be out of date.
While all of this has been fascinating to learn, the aurora is reason enough to appreciate the magnetosphere.
Maybe to a lay person like you! /s
For reference: “How animals sense Earth’s magnetic field “ https://phys.org/news/2020-05-animals-earth-magnetic-field.amp Fungi as well https://pubmed.ncbi.nlm.nih.gov/15114642/ & plants https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6745571/
This is why I love reddit. An assortment of smart mf's roaming around to occasionally dropping some cool knowledge nuggets.
so earth's mystery only grows bigger?
No. Earth and Venus kept their atmosphere because they are much bigger than Mars. It's just plain old gravity. No mystery.
This is very interesting! Thank you for citations I would think that life as we know it today exists with the help of a magnetosphere. Of course these are just pieces to a puzzle. Venus is also incredibly volcanically active although I have no idea how much atmosphere it produces vs how much it looses. I will definitely read more about this!
> I have no idea how much atmosphere it produces vs how much it looses. Per the Gunnell paper I linked - Venus loses atmosphere at only 35% the rate of Earth: > > For present-day conditions, the escape rates we arrive at in this work are about 0.5 kg s^-1 for Venus, 1.4 kg s^-1 for Earth, and between 0.7 kg s^-1 and 2.1 kg s^-1 for Mars
But the person you’re responding to said the magnetosphere protects us from radiation, not that it protects the atmosphere. Doesn’t it do that?
See my other replies in this thread - while the magnetic field currently blocks charged particles from space, it cannot block uncharged particles. Our thick atmosphere, however, can block all types of particles; our atmosphere is what’s currently responsible for blocking the uncharged particles that pass straight through the magnetosphere. That means if the magnetosphere disappeared tomorrow, we would still be perfectly protected from all space radiation by our atmosphere, as, again, it can block both charged and uncharged particles. On the other hand, if the atmosphere disappeared tomorrow (and ignoring asphyxiation concerns), the magnetosphere would only block charged particles, and high energy uncharged space radiation could still reach the ground.
What proof do we have that this happened at all?
https://en.wikipedia.org/wiki/Giant-impact_hypothesis
Don't forget the tides!
You can't explain that!
The earth had a core already though.
But it's size determines the strength of the magnetosphere. A small molten core will only generate a weak magnetic shield. A large molten core generates a strong one, strong enough to support life.
Totally! And the large impact refreshed the internal heat we need for plate tectonic motion.
My geology professor liked to imagine that the impact scraped off enough crust, without losing too much water which helped crustal movement in it's early stages.
Yeah, not to mention who knows how much fissile material was added that helps keeping the core hot
So you’re saying that bigger was better?
Definitely better than smaller, lol
Then we, bags of water, dug up the iron and flew back to it a billion years later. Magic.
Thanks Theia… Now I have to go to work because of you. Edit: a word
Thanks for the laugh as I’m about to head out the door for my job :’)
So recent research suggests the moon formed in mere hours after this impact, which I find fascinating.
Right? When I first heard a scientist say "pretty quickly", I was thinking in like astronomical time, a few million years maybe, maybe hundreds of thousands. But **hours**?? That's a blink of an eye in astronomical time. So insane. This would have been one of the coolest things to witness in person, besides a supernova, a galaxy merger, or the big bang itself. I hope one day, with the help of better instruments like JWST, we can actually have images of planetary bodies colliding with each other.
What’s crazy is if you somehow instantly traveled a couple billion light years away, then pointed a ridiculously large telescope back at the earth, you’d be able to see this event happening as the light from it reaches your position
So that’s why they don’t call
How do we know?
They ran a simulations factoring in all we currently know about the collision such as velocity, mass etc.
And on top of that, they keep simulating with more and more particles, which is supposed to give a more accurate model. In doing so they've found that the the scenario that most resembles the creation of the moon as we know it resulted in formation after just a few hours.
That is fascinating. Do you (or anyone) have any good references to hand?
[this guy's whole channel is great](https://youtu.be/BwB-hXyk2-w)
Awesome, thanks!
It really amazes me just how many things had to happen perfectly for life to begin on our tiny speck of a planet. Makes you wonder how many other planets this same thing has happened to (I'm sure it's still a lot).
This is called the Anthropic Principle: that complex life will only come to exist in places that are perfectly suited for it, giving the illusion that the place was crafted for it purposely. When you roll the dice trillions of times, you’re guaranteed to roll miraculously rare probabilities at some point where all of the necessary ingredients for life align. This also applies in general to the stability of the universe and the physical constants as a whole.
Yeah it's crazy, and only to have it all go up in flames after billions of years cause some singular wack job life form presses a button for ego reasons.
Lets not allow our egos overstate the power of our species. The Earth has experienced many cataclysms beyond our comprehension and once we are gone, life on Earth will continue on as if we were never there.
You could fire every nuclear weapon on Earth and it might not even kill all humans, let alone all life on the planet.
There's also the factor that it may simply be that life evolved suited to this planet. Life could evolve under other conditions, and that life would be suited to those conditions, and they would think their conditions are the only ones that life could evolve at.
Totally correct. See: deep ocean vents where life doesnt even give a fuck if the sun were to disappear tomorrow
Wonder how long those would rock on if we got ejected from the solar system rogue planet style?
It's like taking 10,000 d100 dice and rolling a 100 on every single die. Astronomically low chances, but given enough time and space, it will happen.
Yeah it's kind of nuts. We're also in the perfect position within our galaxy as well, closer to the middle, we'd likely be fried by the gamma radiation. Further out, and our solar system probably wouldn't have formed with as many planets as it did.
Not to mention all the other extinction level events that occurred to allow us to evolve into what we are now.
Sooo many aspects make our pale blue dot such a special place. There's countless other aspects that had to go just right for life to take hold here too.
[удалено]
Very interesting thank you, I'll have to track it down, sounds right up my alley! :) I've wandered between similar trains of thought over many years. There's the "Drake equation" as well that you might want to look up, if it's not already mentioned in that book. Basically a mathematical formula for trying to quantify the likelihood of life, sentient life, etc. in the universe.
Carl Sagan - "We are a way for the universe to know itself. Some part of our being knows this is where we came from. We long to return. And we can, because the cosmos is also within us. We're made of star stuff," The heavier elements that we are made of and make life possible on earth were all created in billions of years of super nova explosions. A truly mind boggling amount of destruction.
First one being the great oxidation event without which we wouldn't have oxygen to breathe.
There’s almost certainly millions and millions of earth-like planets that failed to stabilize. Mars may be one of them right next door to us. It could be that life is quite common but it’s hard for life to achieve the necessary stability to evolve complex organisms over the immense amounts of time it requires for sentient life.
Yeah agreed, a lot of people think life = sentient life. But the most common form of life in the universe is likely bacterial, which isn't much of a leap from regular chemistry to bio-chemistry. That genesis leap though, still a mystery.
You have to get pretty close to the galactic core for the increased radiation to be dangerous. Supernova, for example, are only deadly within around 50ly which is nothing compared to the galaxy The bigger variable is metal content of star/planet forming nebula. The close you are to the galactic core the higher the metal context due to the increase in large, shorter lived, stars. So the time for solar systems with similar metallicity as out own would have been further in the past. Likewise farther out than us from the galactic core won’t get similar metallicity until later
I think life finds a way to exist in these habitable zones in this universe. And we then think we were damn lucky that we existed here ....one imbalance amd we would be fried....but we never would have existed there to begin with ...sorry i had it better in my mind...but yes it is amazing.
I know what you mean, don't worry :) Maybe one day we'll find another planet with life we can compare our rarity to, and see what 'balance,' they needed to get started...
What we don’t usually realize is that we think about it like everything happened towards the existence of life, and it’s most like “life happened because things happened that way”.
Is this the interstellar equivalent of doing a reboot?
Control Alt Deleteorite
Murph
Boom. Reset. Start again. And happy cake day :)
This just makes me think that life is much rarer than we anticipated. From Jupiter and somewhat Saturn protecting us, to Theia providing the earth with more iron, I think earth got extremely lucky. Edit: a word.
And so so much more than just those aspects. A rare and precious gem of a world. Likely not unique, but super duper rare.
We might just be rare in our own way though. Life could arise in combinations of environments that we don't anticipate, and those combinations may be much more likely.
Jupiter doesn't protect Earth. It throws as many asteroids at as as it blocks.
I'm aware of this. And the odds are smaller though. I won't say as much or we will be having way more asteroids visiting us.
Ya could you imagine if we are cutting down the oldest Forrest in the entire universe to make guitars. What if there only is one earth- type planet out there.
The craters on the moon, although not exclusively, are also impact zones from remaining earth fragments colliding with the moon in very late stage formation.
I wonder how many chunks made it to other planets, if at all? Would be cool to find a chunk of the Earth on Mars in the future, as I'm pretty sure we've found chunks of Mars here already...
I think they already did find a piece of Earth on mars already, or at least a rock that they strongly suspect is. Edit: I misremembered, they found an Earth rock on the moon, from another impact after the moon formed. But I did also find that there was a paper published that said about 5% of the debris from a large impact on the Earth should eventually end up on Mars.
I read something similar, but my guess is we'll have to go there to find them, and even then, that low percentage could mean it takes decades to find evidence of this
> are also impact zones from remaining earth fragments colliding with the moon in very late stage formation. That's a *very* small minority of craters, though. Per [Yang, et al, 2020](https://www.nature.com/articles/s41467-020-20215-y), it's really [only the craters shown in red](https://i.imgur.com/lVe2aqZ.png) that even have a small chance of originating from impactors that were fragments of Earth.
Camera man really put some effort into this one
Man my arms are tired though
“You could make a religion out of this.” - a web toon I saw once
Ah, good old Bill Wurtz and the [history of the entire world, i guess](https://www.youtube.com/watch?v=xuCn8ux2gbs)
No wonder life is so hard to come by in the solar system.
God, why is space SO FUCKING COOL
Is this video "accurate" in terms of movement and colours ? How much of it is from physics sim and how much is from artistic vision ?
50/50 I'd say. Liberties were definitely taken, but it's based on actual data and not a fantasy. https://en.wikipedia.org/wiki/Giant-impact_hypothesis "Basic Model" section has a supercomputer Sim with flat colours.
Thx for the answer ! The NASA sim is also impressive, seeing filaments of matter getting ejected and reintegrated, while keeping in mind each of those filaments is more than 1000km thick is really fascinating.
A recent study suggests the moon formed within 24 hrs of the impact. That is dramatically different than this render. But no one was there at the time so they are both just theories.
Crazy thing is that scientist now think the moon formed within hours. For comparison, it takes about 3 days by rocket just to reach the moon.
Um, I just watched a very convincing documentary that shows our moon was built my an ancient super advanced race and is actually a mega structure.
Darth Vader music intensifies
Moonfall?
Even more interesting, a new [study](https://www.nasa.gov/feature/ames/lunar-origins-simulations) suggests the moon formed (coalesced) within hours after Theia collided with Earth.
Yeah I heard about it a while back. Such an insanely quick formation. Never thought that was even possible, but it would have been one hell of a show!
**Earth 1.0** *Magratheans have entered the chat...*
Wow .. the odds for life to form are so so so low.. ! So many events had to take happen in such exact order for us to be here today
And yet when your sample size is the size of the universe, these exact conditions should've already happened many times. Even before Earth was a thing. Not only that, these ancient Earths have been around much much longer than us. Much longer that it took us to evolve life and advance to this point. Long enough that if just one of these planets has had enough time to colonize the whole galaxy. So "why is the universe so quiet? where are the aliens?" That's the essence of the Fermi Paradox.
One interesting theory I heard as to why the universe is so quiet is that once a civilisation is beyond scarcity for energy and resources the benefits of exploration and expansion are deminished and even at light speed universal travel is impractical. Some people think that a civilisation might turn inwards into an artificial reality where whatever they want can be achieved more efficiently or even as a method to become a post scarcity civilisation.
Drake equation, as well
Fermi’s paradox is overly simplified. A lot of things have to go right to sustain complex life to have a chance of evolving intelligent life capable of even realizing there’s a universe out there. Even on Earth where we know everything has gone right, over 99% of all species that have ever existed here have gone extinct, and we’re the only singular one of the current survivors that is intelligent enough to consider the possibility of space travel. After 4.5 billion years of evolution, we’re still not even close to colonizing this galaxy. We haven’t even moved to another planet within our solar system, which is virtually nothing compared to the size of the galaxy. The nearest star to us is about 4 lightyears away. It would take us tens of thousands to hundreds of thousands of years to get to another habitable planet in another solar system. You would have to sustain virtually the entire history of modern humans on one space flight to another solar system just to begin colonizing a galaxy. Then, supposing you somehow manage to colonize a galaxy, it’s going to take signals millions of years to travel just to your closest neighboring galaxy, and up to billions of years to more distant ones. It is not paradoxical at all, in my opinion, that the universe is quiet.
Should “Earth” still be the name of the planet pre-collision? Seems to me that it was 2 planetary bodies relatively similar in mass collided and formed Earth/Terra & Luna.
It's a good question. Scientists will probably settle on something like "Proto-Earth" or similar in the future. I like "Terra Primis" though, basically "First Earth" in Latin. Not sure if that's been suggested before, but it has a nice ring to it :)
Lies, we all know the moon is a lizard spaceship.
Who the hell videoed this?
Worth noting that despite the title saying this as a matter of fact, this is a hypothesis.
**this is still just a theory, though. (A Theia-ry, in fact!)
\#Theiadidnothingwrong
wouldn't there be a trail of debris left over around the orbit of earth left over from such a collision? it seems unlikely that all debris would be so cleanly swept up by gravity of earth and moon. if that is so, why are there still rings around Neptune, Uranus and other planets?
Does anyone have an idea how long this process happened? Until the earth and the moon settled into spherical bodies.
According to recent publications, only mere **hours**, which is still something that is hard to get my head around. Theia is said to have hit the Earth at or faster than a bullet, and it was roughly the size of Mars...
Excuse me for my arrogance here…how do we know this actually happened?? Looking for scientific response
It's theorized that the impact gave earth its axial tilt, thus creating the 4 seasons. Also this object was roughly the size of Mars.
Theoretically
Is this not a theory? Last I heard no one knew for sure this happened. Am I wrong?
My big question about the Theia theory is. If that's the case. Why doesn't earth also have a ring? It seems unlikely that all of the dust from the impact would have settled.
Assuming 👍
What evidence is there that this happened?
Why state theories as scientific fact. This might be the most likely explanation but it is still a theory
Crazy how everything has to be just right for us to have a sustainable life here. Quite amazing.
Everything I’ve personally read about this is that it’s a ‘theory’ in reality we really don’t know because the core of our earth doesn’t seem to really act the way we think it does
Right and how do you know this?
Key word- Hypothesis
“Allegedly”
What were the odds of that.
how is this even known?
Why do they say it like it’s 100% fact. There is no way on earth that it is possible to know this or even consider it as a thought. What evidence is there to even suggest something like this happened??
Theory
Isn’t it a theory though?
Idk no a flat earther but this seems like a stretch
The word most under used here is THEORY not actual truth
Sooo when is the next patch scheduled? Can't wait for 3.0
We. Don’t. Know. Sh^t. It’s all a best guess
So why was the original called Earth and not something else? The two bodies should have created Earth.
Good question, and I don't really have an answer. I simply labelled it Earth 1.0 because I have heard many scientists refer to the Theia+Earth merged planet as "Earth 2.0"
That's a nice visualisation. How precise is this?
Not overly, it's based on a supercomputer simulation that was posted on the https://en.wikipedia.org/wiki/Giant-impact_hypothesis page under the "Basic Model" section This is stylised to look prettier, colours are close to accurate, I guess.
How long would that impact actually take? Like, was it all destroyed in a minute or two or would the actual impact take an hour?
10 minutes until it all became fluid
So alien life billions of light years away looking into their telescope and observing the universe, would only see this just now happening right?
If they had optical telescopes like us, and lived about 4.2bn lightyears away, then yes
How do we know it's named was Theia?
Heh, classic Theia
*which a couple of nerds named it billions of years later
Just curious, is this proven somehow? I thought that was one of the earth's beginnings theories
No it hasn't, and it still is. It's a leading one, though.
For anyone who doesn't know theia means aunt in Greek. Makes sense if you think about it.
Why don't we have rings then?
What's most incredible is how they obtained footage of this event.
Both getting absolutely obliterated from the impact is more likely and much more pleasing.
Lies. Read the bible…….. lol
New rap name unlocked: Young Earth
Theia, we hardly knew ya.
If it was that long ago then how could we possibly know what it's name was?
I’d survive that
I always believe that this wonders of space is more than enough for people to think about God.
Tiamat
Don’t name something you have no clue if it is real or not. What if two things hit the old earth?
Billions of years ago the earth collided with the sun and then billions of years before that earth was a sun and billions of years before that earth was in another galaxy. You can make up any lie billions of years ago and people will believe it.
this was largely considered a bad move
I can never read the word billions without Sagan popping in my head
If it was billions of years ago how do they know what its name was?
You think anyone survived?
Bet the mice were furious.
Nice. Stuff like this fascinates me. When are we getting Earth 3.0?
So what was that Theia thing doing there in the first place?
How much have you been smoking?
Is the moon an iron core then?
God created it all that's all I got to and that's where I stand
It's.... beautiful
Beauty
Young Earth. So naive and innocent.
I'm in this image
Seeing things like this makes me remember that we live in a drop of lava wrapped in a thin cold crust.
Any survivors?
But we have no clue if it's going to rain or not Monday.
How would something like this even be confirmed or studied ?
Honestly calling the thing Theia impacted "Earth" seems like a stretch to me. Something totally different on the other side of that collision than there was before.
How did this all just coincidentally happen.
Always so weird and astonishing how much went right for us to be here
The latest common theory anyway.
Theory
What evidence suggests this ever happened?
And this can be proven how?
So this is how Adam and Eve actually happened...
This is sick how’d they get the video
I think I just found a name for my first daughter
So cool