: Last Updated: 17 April 2024

The kiss of planet Theia

This article The kiss of planet Theia was originally an integral part of the parent article "Why are we here?", but given the fact the parent article was growing extremely huge, I decided for the sake of simplicity to have the section "The kiss of planet Theia" on a separate thread for simplicity and easy reading. See below the summary of the main article "Why are we here?" and the location of The kiss of planet Theia, in section 2 article 1. I recommend and encourage you to read all these articles in order (after all, they follow the chronological order of our creation) so that you get the whole picture of really why are we here

Section 1, our star the Sun, without it nothing will be possible

Section 2, the perfect position of planet Earth in the Universe, and the chain of random accidents that caused your existence

The kiss of planet Theia
Diving into the origins of Water
The spark of Life
- List of Extinction Events
Jupiter, the Great Benefactor
In the wrong side of the Congo

Section 3, the abstract of your thoughts and the illusion of control

1. The kiss of planet Theia - 4.5 billion years ago

9.2 billion years of time have passed, and as far as we know nobody was there to ever tell the story. At this point of the article we reach a stage where the Earth is finally formed... kind of...at this moment we should call our beloved planet "Earth minus 1" (also called Gaia by scientists, but I much prefer to use the name Gaia for our current planet). At this moment in time, our "planet-to-be" is about to face one of the most significant transformation that makes it the special home in the Cosmos that we know it today: the only planet where Life exist. It all started 4.5 billions years ago, when Earth -1 was hit by an object the size of planet Mars, to what would be (we hope) the last planetary collision that formed planet Earth, Gaia. It is thought that the inner solar system must have been a very crowded place, with about 20 protoplanets (planets-to-be) down to the 4 rocky planets that we know today (Mercury, Venus, Earth, Mars, and maybe the asteroids belt too), therefore collisions must have happened in the past to reduce that number from around 20 to 4 plus the asteroids belt. Only collisions with other big objects can explain why the Earth is spinning so fast, while Venus... rotate backwards, in retrograde mode; this sort of collisions can also explain why Earth is the biggest of the inner rocky planets while Mercury, who probably had very few collisions, is tiny is comparison to Earth. With every collision that Earth -1 was encountering, its surface and part of the mantle was smashed to pieces, and obviously from the early beginning when Earth was just the size of a continent in space, the heavy materials began to sunk to the center, like nickel but mostly iron (symbol fe), the last of the materials that a star can create just before going supernova. The iron inside Earth must all be very ancient, probably originated from the leftovers of the star father to our Sun, before it went supernova. Iron is a special material, the gateway mineral to other dimensions. It is interesting to know that Iron is both the death cause of a star (when a star starts producing iron, it just got days lo live) and the reason planets like ours are able to sustain Life, as it powers our magnetic field, not to mention the fundamental weight that iron and its subsequence alloys have at the time of empowering and sustaining the infrastructure of our civilisation

It is still very debatable the state of Earth -1 (Earth minus one) prior to Theia collision, and in fact whether the accretion disk theory is valid or not, but without any doubt (you can feel it under your feet) the Earth was indeed formed, and massive collisions with other planets, fighting all for an undisputed space to orbit around the Sun, must have happened in the past. The picture below is a theorised aspect of how the Solar System would have looked 4.5 billions years ago or so, with nearly 20 planets rotating an infant 1 billion years old sun. It is just pure chance that we ended up with 4 inner planets, had the collision of those hypothetical 20 bodies behave differently, we could have end up with 8 inner rocky planets, or even just one, like some of the gigantic exoplanets that we keep discovering nowadays in other solar systems, most of them too hostile to hold liquid water, and therefore unable to host Life as we know it (good to hear that Kepler-62e and 62f could be an exception!). Where did all the rocky material to from our planets came from anyway? Must have been orbiting around the nebula from which the sun's hydrogen collapsed and ignited. As mentioned before, Hydrogen is a gas that, for us here on Earth, takes a lots of effort to compact: it turns into liquid when under pressure. Maybe hydrogen in space behaves differently, perhaps it interacts with dark matter, and it can actually compact an ignite in the vacuum (it definitely ignites somehow, otherwise there would be no stars in the Universe!)

In any case, it is thought that, at the time of this last mayor collision of planet Earth, its surface was completely melted, as if it had already experience very recently other significant impacts, or perhaps it was under the extreme pressure of the imminent collision, getting hotter and hotter with every revolution Earth vs Theia were practising around the Sun, and the surface began to melt by the tidal gravitational waves of Theia. Definitely, right after the impact, the Earth surface was nothing but an immense ocean of liquefy rock, nothing was solid. Only this state of liquefied rock on the whole surface of Earth can explain why the Moon density and rocks composition are so close to those found in the surface of our planet. Literally all the mantle of liquefied rock that was covering the Earth was flown away after the impact. The planet that collided with Earth, as you already guessed, is called Theia, wisely named after the Greek mythology mother of the Moon. In this picture below you see at scale 1:1 a representation of Earth, Mars and the Moon, so you get the idea of how a planet the size of Mars hit our planet (which in the picture below -prior collision- must have been smaller), and that from that collision an object the size of the Moon formed out of the debris. No one is to say that there probably were two or three moons after the impact, but whichever objects were orbiting Earth, eventually they all gather together though the gravity-cannibalism process into our current Moon. The Moon moves away from Earth at a rate of 3.4 cm per year, still driven by the initial separation force of the impact

This collision defines the character of our planet: we are the product of this primeval accident. The collision is rare because it happens (and it was MAJOR) just after the planet is form, when normally this sort of massive collision would have happened during the creation of the planet. For many many millennia, if not millions of years, Theia and Earth -1 were in a collision course. Perhaps every year, during their orbits around the Sun, they draw closer and closer to one another, maybe others collisions around the solar system altered their orbits, but eventually Theia crashed into the Earth (notice that it wasn't the other way around), and luckily for us the Earth remained on an stable orbit around the Sun after the impact, without the risk of colliding with any of its closest neighbours. You might argue that this event does not make our Earth any special than other planets. As mentioned before Venus, Mars and Mercury also had collisions and that's why some of them are bigger than others (the more matter acquired during the collision, the bigger the planet). And surely there must have been many collisions in the Universe similar to that of Earth vs Theia... who knows how many! One for every Solar System? That would be millions and billions of collisions....however... for life to exist after a collision like that on Earth the following factors must all be met to a staggering precision:

Theia was the right size of 1/3 of Earth (the size of Mars). Had it been smaller the force of the collision would not had been powerful enough to eject enough matter from the surface of Earth that will eventually create the Moon, which is of utmost significant to support life on Earth, as we later on will see. Had it been bigger the monumental energy of that collision might have split the Earth in two planets. But nope, the collision was of the right size, and for millions of years after it, our planet must have had rings, just like those in Saturn, while the Moon was still forming and acquiring the material from those rings. How often this radio of collisions 1: 1/3 occurs? Okay, there might be collisions in every Solar System during its formation, but that of a radio 1:1/3? The odds of a similar collision like that on Earth occurring somewhere else in the Universe, have now suddenly been diminished
Theia was travelling at the right speed for the collision to be kind of "gentle", something like around 4 kilometres per second (the asteroid that wiped the dinosaurs, just a tiny fraction of what Theia must have been in size, was travelling a lot faster in comparison with Theia, at an estimated speed of 30 kilometres a second). Had it been faster probably the debris (and hence the Moon after the collision) would have been flown away escaping Earth's gravity. Had it been slower and the debris would have fallen into the Earth and the Moon would never have formed. What are the odds of this "tender" kiss of Theia happening everywhere else in other collisions? The planet must have been dragged by others through hundreds of revolutions around the Sun, and when it finally hit Earth -1 it was moving slow, wiping the surface of Earth -1 with a gentle but determine push
Theia hit with the right angle. The collision wasn't back-to-head, or worse head-to-head, which would have happened if they were orbiting in different counter-clock rotations. Needless to say that Theia must have been orbiting clockwise around the Sun, just like Earth and all the other planets do, otherwise the collision, had it been head-to-head, would probably have created a flat surface of compacted iron and metals of no use... was perhaps the alien visitor Oumuamua of 2017 created like that? This right-angle of collision had the crucial effect of causing the Earth to start spinning really fast, kick-starting a long lasting geo-dynamo effect, when the core melted by the collisions and the upper area of silicates in the nucleus started rotating faster than the interior of iron, creating the magnetic field that protect us from ultra-violet and gamma rays of the sun
Theia was composed of the right materials: surely rock, but Theia must have been very rich in iron too. After the collision, the iron of Theia was absorbed by the Earth, sinking down into the nucleus and strengthening the magnetic field of our planet that makes it deflect the deadly radiation of the Sun, by protecting the ozone layer and other gases from erosion, which filters those deadly rays. That may explain why the inner core of Earth is so rich in iron and nickel, and so big in comparison with the planet itself. Theia literally gave fuel and kinetic energy to Earth, so that it can power its magnetic field, that as we know is of critical importance to life on Earth; without it, the gamma rays (radioactivity) will have prevented any cells from grouping because these high energy rays penetrate anything and destroy any DNA that could have been formed. Life on Earth will not exist on our surface if it wasn't for the quick rotation and iron composition of our planet, that powers our magnetic field. Some ultraviolet radiation is actually needed at the beginning on the planet's life, so that organic life can be started, but there are after some sort of mechanics (like a magnetic field) need to be develop by the planet to preserve that organic life

So we have to really be thankful to Theia, this "random accident" set the right conditions for our planet to host life. After the collision the atmosphere of our planet was reset, gone, kaput, it was composed then of of rock vapour, which eventually condensed, was there any water there? I'll look into that on the next chapter. The Moon formed as a ring first, it is estimated by psychics calculations or the current orbits, that right after the impact the orbit of the Moon took 20 days while the days on Earth were lasting 6 hours only

Here below there another video of the kiss of planet Theia, of the impact. This one has been created recently by NASA showing that the Moon may have formed in just a few hours.....very, very optimistic predictions. Then again, way more research is needed "in situ", in the Moon, to dig deeper into the details of this collision. Scientists keep trying to find Earth-1, but that planet stop existing the minute it collided with Theia. The end result is our planet, Earth, Gaia, the child of a planetary kiss between Earth minus one and Theia

Furthermore, the collision left our planet still on the Continuously Habitable Zone (CHZ) of our star, what a relief! Nobody knows if our planet was already on that habitable zone prior the collision, maybe we have to thank to Theia too to leave us right in the center of that blessed zone after her kiss! The habitable zone is a defined area around the Sun were water can exist in liquefied and vapour form, and which borders are still very debatable, with the idea that both Venus and Mars (each on them on opposite sides and at the edges of the habitable zone) also hosted liquid oceans in the past, and had the capabilities of hosting life. Being on the HZ doesn't necessarily means that the planet support life, is just an indicator, meaning that chemical reactions suitable of supporting life are more likely to happen on that area, where water can exist in a liquid state. We need to make a differentiation between the Continuously Habitable Zone (CHZ), the one we are an that is constant during the main sequence lifetime of a star, and the actual Habitable Zone (HZ), which may only last for a few million years. For example, in a few billion years from now the Sun will lose his hydrogen, and start expanding, incinerating planet Earth during its way. For a brief period of time, maybe a few million years, both the moon Europa of Jupiter and the moon Titan of Saturn will be on the Habitable Zone of our star, so Life can potentially manifest during that period in there. However, these moons are not in the CHZ, so whichever life forms can be created while they are warm, will be short lived because with the relentless expansion of the Sun, they'll also be incinerated and reduced to dust, not sure if they will have enough time to question why are we here

The Moon, like the Mother, is a giver of Life, literally. The Moon creates frictions and drags that slows our planet, causing the atmosphere to be more benign without so many powerful hurricane forces. If the Moon wasn't there, and considering the rapid rotation of our planet, each of the hurricanes that will form would be absolutely devastating. Without the Moon, and the 'smooth' tilt effect that it has on us (wobble), there could had been two possible outcomes: either the Earth would have had no tilt meaning that everywhere will receive 12 hours of day/night, just like Mercury, cold will always be freezing and hot will always be an boiling, obliterating the surface, or we would have had an exacerbate tilt, meaning that the North Pole would be in almost the Equator during summer time and vice verse. Both scenarios are part of Science Fiction thanks to the existence of our Moon, which provides a sinuous tilt to planet Earth, enable sessions stations (Winter, Spring, Summer and Autumn) and essentially nurturing life

This impact was also the direct cause of the rapid rotation of our planet. We know for fossil records that, in the distant past, the Earth was rotating much faster, and that is actually slowing as time pass by. Right after the impact, it is estimated that it must have been spinning at a rate of 5/6 hours to complete a day. We know this because of coral fossils, dated 4 billions years ago, showing on the filaments of deposit that a year lasted 410 days, meaning the days must have been shorter. Once the planet cooled, the gases condensed and water began magically appearing on the surface of Earth, and that is when the role of the Moon became to be decisive, as it regulates the fast rotation of Earth, stabilising the wobble of the poles and that of the Earth itself at an angles of 23 degrees, preventing that the North or South pole move further beyond an inclination of 23 degrees from its spin axes. Complex life forms would have been impossible on Earth, otherwise, with drastic changes of temperature that would have make the timeline of evolution to stop at the single cells barrier. Just imagine that every year, for 3 or 4 months, the North Pole of our planet falls into the city of Rome, and around that area you get 70 or 90 degrees Celsius below zero. This rapid shifting of the poles is regulated by the Moon, which just happens to be of the right size too, to effective and efficiently have the gentle gravitational force to prevent the wobble of the Earth from creating extreme temperatures on the surface, yet allowing a mild-wobble, that causes seasons like winter, spring, summer and autumn, fundamental aspects of the mechanics of evolution. I know I am repeating myself from the previous paragraph, but I love it! I find this impact so fascinating

In addition to all to these "fortunate" circumstances, another incredible benefit of Theia's impact was the creation of our magnetic field. See the picture below a comparison of Venus, Earth and Mars effect of the solar wind over their individual atmospheres. None of our neighbours have a significant magnetic field that deflect the deadly sun rays. This is disappointing particularly when looking at Venus, our twin-planet, of similar size to Earth and expected to have a similar size of iron core, yet no magnetic field. After all, both Venus and Earth were formed in exactly the same conditions, so how come they evolved so differently?....well, that's the thing: they did not form with the exact same conditions. Venus's rotation is extremely slow, a day takes half a Venusian year, while our day last only 24 hours. Our Earth was gently kissed by Theia, kick starting the magnetic field, and that was the beginning of a history of love between Life and our planet. Every time you see a shooting star, burning bright in the pitch black sky as it kisses the atmosphere, think that that piece of rock that you have just seen burnt could well be a leftover of Theia's collision, still a reminder of the eternal kiss of love in between these two planets

And you might wonder... all right, how do we know all these thing happened? Nobody was there during the collision to take a snap and upload it to Instagram, right? For those silly cows who still believe we did not reach the Moon, I've got a surprise for you: we did indeed landed in the Moon. The Apollo missions 11, 14 and 15, back on the late 1960s and early 1970s, placed some special mirrors on the surface of the Moon, which helped us measure 'exactly' the distance between our planet and its satellite. It turns out that the Moon is receding from Earth at a rate of 3.8 centimetres a year, roughly the same rate at which your nails grow. If the Moon is receding, that means that in past it must have been closer, right? You do the calculations, going back in time, and it turns out that around 4.5 billions years ago the Moon was just 22,000 kilometres from our planet...while now (at its closest approach, the perigee) is at approximately 363,000 kilometres, that's a clear indication that the Moon formed out of debris circling planet Earth, debris product of a collision. Besides, the rock samples that the Apollo astronauts brought from the Moon, show that the surface of the Moon is a burnt version twin of our planet, and that both have the same origin, both were one part of the same thing. Like Tony Robinson said on the Catastrophe British Documentary series: "we are here by chance; we survived, 99% of all the species who ever existed, didn't"

What part of our planet did Theia hit? This is a really tricky question, but I want to know, and in spite of that collision happened 4.5 billion years ago, and given the fact that the aftermath of its effect are clearly perceived nowadays (fast rotation of our planet, for example) I believe that some scars may have been left on the planet, right? I am probably talking nonsense, but the South Atlantic Anomaly (SAA), a distortion on our magnetic field, has all the needed shape and position, right close to the Equator, to reflect the point of impact of Theia, and there is evidence that this anomaly is at least 11 million years older, could it be much much older? And if my supposition is right and the South Atlantic Anomaly is the actual place where Theia hit, what where the effect of such immense impact on the other side of the globe? Could the feature called volcanic ring of fire, around the Pacific Ocean, be a result of Theia's collision? I know the magnetic field of our planet formed after Theia's collision, and that the ring of fire is a plaque tectonic development way younger than Theia's collision, but I like to present the reader with this sort of questions (where did Theia collided?). We are not afraid of asking, and every possible explanation should be investigated. The existence of the Large low-shear-velocity provinces (LLSVPs), irregular structures of the mantle of our planet, could also be an indication of where Theia made its kiss

Is this where Theia collided?

Is this where Theia collided? Credit: The CHAOS-7 geomagnetic field model

Should we still study LLSVPs? The kiss of Theia

Credit Should we still study LLSVPs?

Thanks to Theia, the stage to support Life in long-term conditions was setup on our planet. Now, the time was ready for water to appear on the surface and for some chemical reactions to occur undisrupted for billion of years. To close this chapter nicely, let's recap the conditions so far of our planet to support life. If any other planet fail to account for any of these bullet points, game over for Life!:

The star hosting the planet must be on a quiet area of the galaxy, safe from supernovas that will sterilise the prospects of life, and safe from invisible black holes too!
The star must be at a safe distance from its neighbourhood, to prevent collisions or unexpected visits during the life of the planets subjects to host Life
The star itself must be very stable, shinning steadily for billions of years. Come on, our sun has not taken a break even once!
The planet must be positioned in the habitable zone of the star, for liquid water to form on the surface. Water is a key element for chemical reactions to develop into Life
The planet must have a magnetosphere or something to deflect or reduce the amount of radiation coming from the parent star, radiation that otherwise will sterilise the planet
For a magnetosphere to be powerful enough to do that, the planet must be spinning fast
For a magnetosphere to be powerful enough to do that, the planet must have enough iron on its nucleus to behave as a geo-dynamo and generate the magnetic field
For the planet to spin fast and also has enough iron, some sort of collision must have occurred on the planet during its birth, to ensure its spin motion is fast enough for the effect of geo-dynamo to manifest. Without the extra push of a collision, and had the planet had a magnetic field from its very origins, this one would have shutdown half-way through the life of the planet, which is probably what happened on Mars
A Moon or other mechanism must exist around the planet, to counteract for the fluctuations that such a rapid spin may produce on the surface of the planet, like extreme temperatures that will compromise the evolution of Life
A big protector, like Jupiter or similar, must exist to absorb comets and collision that otherwise will jeopardise the evolution of Life on that planet, resetting it every time a major collision occur
Plaque Tectonics must be present in the planet to drive the dynamics of the weather and release heat from the interior in a timely fashion, else the planet may experience "basaltic eruptions" in an aim to lose heat, like those occurring in Venus which will flood the surface with lava every half a million years or so and chock the atmosphere with CO2

Even the kiss of Theia had an impact in the long run in our civilisation, with the creation of the Lagrange Points that are so useful nowadays by our spacecrafts, they do exist thanks to the presence of the Moon, and hence due to Theia's collision with Earth -1

Yep, there are 100 thousands million stars in the Milky Way alone (1 plus 8 zeros: 100.000.000). If each of those stars had a planet like Earth, how many of those will match these 11 conditions above? If each of these conditions only appears on 1/10 (one tenth) of the planets, that means a probability of... 0.01 planet. In theory, we shouldn't even exist

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