Researchers at the Faculty of Physics at the Technion have solved a scientific mystery concerning a critical stage in the formation of planets. The new model has interesting implications for the idea of panspermia - the transfer of biological material between different planetary systems
Researchers at the Faculty of Physics at the Technion present a new theoretical model for the development of planets from "seeds" coming from other planetary systems. The research of Prof. Hagi Peretz and doctoral student Yevgeny Grishin was published in the scientific journal Monthly Notices of the Royal Astronomical Society.
In the early stages of the formation of a solar system, before the planets are formed in it, there is a disk of dust and gas around the young sun. This disk provides the future planets with the raw material for their creation. Apparently it is a simple process in which grains of dust adhere to each other and form lumps of matter that grow larger and larger - stones, from which rocks are formed, which unite into small celestial bodies that collide and adhere to each other until an entire planet is formed.
But to her and a thorn in her side: in the aforementioned theory of aggregate growth there is a bottleneck in the transition phase from small stones (a centimeter to a meter in size) to celestial bodies with a diameter of a kilometer or more. The physical conditions prevailing in protoplanetary disks include very strong gas flow that is expected to erode these rocks and even slow their motion. When the movement of the stones slows down, they are expected to be drawn to the center of the disk and be swallowed up by the Sun. In addition, collisions between small stones are not expected to lead to their adhesion, but rather to their scattering from each other. In other words, small rocks and stones are faced with the "meter barrier" - a developmental stage where their limited size reduces their chances of survival and growth.
"The normal model suffers from a significant bottleneck," says Prof. Peretz, "since it requires an unreasonable leap over the 'valley of death' of the transition from dust and stones to the order of kilometers. This is why astrophysicists around the world are looking for an alternative explanation for the development of celestial bodies larger than a kilometer. Once the diameter of the nascent mass exceeds a kilometer, the existing model works well - because at this stage the object manages to absorb smaller objects that will turn it from a 'planetary embryo' into a real planet. The problem is in the stage before that."
The article by Grishin and Prof. Peretz draws inspiration from the drama created in 2017 by the interstellar body Oumuamua - an elongated body that entered the solar system and was detected in various observations. The discovery of this object gave rise to many different hypotheses, but one thing was clear: it came from outside the solar system. Omuamoa verified old scientific estimates that the interstellar medium - the material found in the space between the different solar systems - is full of holiday rock blocks. It is commonly assumed that such remnants are ejected from various planetary systems in the early stages of their formation.
According to the model proposed by the researchers from the Technion, Omoamua and objects larger than it wander between different solar systems, and some are trapped in the preplanetary disks of young suns. If we take the specific case of the Earth as an example, then like every planet in its embryonic stages, the Earth too was preceded by a pre-planetary disk of gas and dust that surrounded the young Sun. According to this model, this disk captured a large block of rock from another planet and around it, in a long process, the Earth as we know it today was formed.
In conclusion, the key to solving the mystery of Death Valley lies in interstellar objects that come from other planetary systems and are "seeds" for the development of new planets. Put more poetically, the researchers explain, “No planetary system is an island; Planetary systems are created from seeds that came from other systems and later produce their own seeds, which will be sent into space and give birth to new planetary systems."
To assess the feasibility of the innovative model, the researchers developed a mathematical model that examines the probability of such "seeding" occurring. They discovered that the required capture of objects in preplanetary disks is not a common phenomenon, but it is certainly probable.
The innovative model has additional interesting consequences in the biological and evolutionary aspect. According to Prof. Peretz, "If we understand that rocks may pass between different planetary systems, then there is a new model of panspermia here - a transition of life between these systems. In order to capture active biological material, and allow it to survive such an interplanetary journey, a rock with a diameter of a few centimeters is enough, so if we are talking about a rock with a diameter of a kilometer, the possibility that it will be able to preserve bacteria or other biological material is not far-fetched at all. Panspermia is not a new theory, but our model provides an explanation for its feasibility."
The research was supported by the Irwin and Joan Jacobs Fellowship for Outstanding Graduate Students, the National Science Foundation (ISF), and the Minerva Center.
For the full article atMonthly Notices of the Royal Astronomical Society
More on the subject on the science website
20 תגובות
I'm sitting at the computer and the window is open without air conditioning, the air is excellent and a light breeze is blowing, a great day.
I think that in the end everyone is right, it is hard to digest that the planets in our system were formed by balls that came to us from other systems, perhaps they came from the material between the planets which are large and did not manage to actually form their own solar systems.
Nature should be allowed to do its thing and we should look for solutions and most importantly give the world's citizens an answer to the problems of life and existence, climate and livelihood.
First of all, this site is a site designed to teach and bring publications from the forefront of science to the general public. I will ask that everyone's responses be substantive answers and not insults and profanity.
Having written this, Ariel, the misunderstanding is probably on your part, not mine. Read exactly what I wrote: I wasn't talking about growing objects through collisions in chain reactions; I referred to what was written in this article, according to which the people of the Technion apparently solved the difficulty in the "barrier" mechanism for the growth of particles in ancient dust clouds, as they were at the birth of our solar system (by the way, I myself have never heard of such a barrier, but ...) - to mention: it is written that particles of the order of meters cannot continue to grow in the same mechanism of dust and object accumulation until reaching objects of the order of kilometers - when the latter - after their creation - can continue to grow. The "solution" that appears here, according to which the arrival of a large rock from outside the solar system is necessary to solve this problem sounds "strange" (to say the least) to me, which is similar to the foolish "logic" of the "turtle tower" model from the Middle Ages.
A. Ben Ner and Ariel - you must have heard of the theory according to which the early solar system contained about 30 small planets that eventually created the four inner rocky planets; What are the chances that 30 - or more - "large" objects (as mentioned, on the order of a kilometer or more) will arrive outside the cloud boundaries of the early solar system, and will concentrate only in such a narrow band around the sun - and all of which will also move and cluster in the same plane (plus-minus 6%)? And what are the chances that this is also what happened in other solar systems (discovered by various researchers during the last two decades), in which several "super-Earths" were also observed?
I would love to receive a serious scientific explanation for my question from someone who thinks I'm not "arrogant and evil", with reference to the sections I raised.
How good it is on a hot day to sit next to the air conditioner, and of course, to comment on science articles!
and for our purposes.
Of course, I agree with all those who oppose the explanation of the "importation" of basic building materials needed to create planets from other solar systems, for the purpose of creating planets in our beloved solar system.
And so, I cross my fingers to Conan and others in attacking them just for bringing up the idea that is contrary to the spirit of the article.
For example, the respondent A. Ben Ner, defines Conan's answer as "arrogant and stupid" and added, followed by Ariel, who says that Conan's response shows a "lack of understanding of what is being read".
It seems to me that Conan actually read the article and understood it well, but, what to do, he thinks the article is not scientifically based. If there is a problem of growth from meter to kilometer, the solution will not come from "importing" a kilometer from another solar system.
My private and humble opinion, I don't think there is a problem, and there is no limit to growth. Two meteor asteroids moving next to each other, it is inevitable that they will come closer and stick together during a gravitation that works for millions of years.
The commenter Yehuda Elide brings up a nice idea that we didn't give any thought to, that perhaps electromagnetic forces actually help in connection. I wouldn't dismiss this idea outright.
In short, "sending the problem" to another solar system is not acceptable to me (and others) even if it is given by the best Technion scientists whom I greatly appreciate.
Please respond gently
And may the air conditioner not break down on this hot day!
Sabdarmish Yehuda
"there is"
That is, I meant to ask how the first large rock blocks in the universe were formed (those with a diameter of tens and hundreds of meters) if there were not earlier "rocky seeds" that they could have crystallized on?
"b but b"
Conan,
Your response shows a lack of reading comprehension.
Nowhere is it written that the creation of a body of a size of a kilometer or more is impossible. What the talented scientists at the Technion have shown is that it is enough for a few objects of this type to be created and these will start a chain process that will allow the creation of planets.
It seems to me a bit like the chicken and the egg question, the theory is nice but how were those rock blocks that came from other planetary systems formed? How did they themselves form?
PanaSpephmia
to conan
Your answer is unfortunately both arrogant and stupid.
It would have been better if you had tried to understand the matter in question before sending your stupid comment.
I tell you in short that, the issue in question refers only to the process of the formation of a cloud of dust. Move in an elliptical orbit around a star, to a planet. All this does not mean that in other processes occurring in the universe (for example the explosion of a star), bodies of different sizes, including bodies of a meter or several meters in size, cannot be formed and ejected into the intersolar space.
No one faces infinity
Is it not alohistic to seek an answer
Do educated guesses bring blessing
Does panic at our zeros motivate the questioning
This publication is really an insult to the intelligence of every person - astrophysicist or not.
This article begins by describing the problem according to which it is very difficult for planetary bodies to pass the growth barrier (= the area between a meter and a kilometer); So what do our talented scientists at the Technion do? They simply bring a body outside the solar system that is already a kilometer in size, and say that it will continue to grow and form a planet. But Lord of the worlds - how was this specific body created?!?!? How did this body from outer space manage to cross the growth barrier??? And why can bodies larger than a kilometer form only in outer space and not in a disc of dust and gravel, where there is a higher chance of damage and connecting small particles?
A "scientific" theory that claims that it is necessary to bring a large body (which no one knows how it was formed) outside the disc of the early solar system in order for planets to form reminds me of a very similar argument from the Middle Ages, when the popular assumption was that the Earth (in fact then it was believed to be a flat plate and not spherical ) balanced on the carapace of a giant turtle. When the skeptics at that time asked: "Wait, but what is this turtle standing on?" The answer was: "What do you mean? This turtle is standing on top of another turtle, which is also standing on top of another turtle, and so on - all the way down!"
Really absurd. If these are the theories that senior physicists develop and publish in international professional media - it is clear that the human race is still in the dark ages.
Not the best at astronomy. But this is a theory based on models.
It actually seems to me that the matter of the particles sticking together and as they grow, they absorb more... It doesn't really make sense to me because it looks like a collision to me, and if a collision at what speed? And then everything fell apart
I do not understand
Let's start with the fact that this is just a theory.
What are you looking for, everything will be found in the Torah, Book of Genesis.
Don't think that I wrote it, I just threw in dots and they alone connected and became a sentence.
Only four dots remained as they are and became a period at the end of a sentence.
There is still something essential missing in the model
For more than a century, all the models proposed for the process of the formation of planets in star systems, including Earth in the solar system, assume by default that the material that accumulated in the cloud of gases and dust came from previous systems and perhaps also from more "ancient" galaxies, where they were enriched with new "heavy" elements, formed in the cores of massive stars and were dispersed in supernova explosions even before the conditions for the formation of massive bodies within the local cloud were created. So what is the problem with the orthodox models? It has two sides: on the one hand, the gravitational pull between two dust particles is negligible relative to the "thermal noise" (Brownian motion) that tends to separate them. On the other hand, a particle embedded in a relatively homogeneous gravitational field, created by a uniform distribution of particles and stochastic motion, will not be attracted to any other particle with the preference necessary to create crystallization nuclei. The model proposed by the Technion researchers seemingly provides a Deus Ex Machina solution to the problem of the size of the nuclei, on the assumption that these arrived already crystallized from previous systems and all that is left for gravity to do is stick enough layers of dust to the large rock that arrived outside the system so that it grows to the dimensions of a planet. Can be. But like any Deus Ex Machina solution it leaves a feeling of missing a more fundamental explanation.
I think we need to attack the problem from a different point. Not how we will "invent" a crystallization nucleus by importing ready-made nuclei from other systems, but what force can replace gravitation at this stage of dispersing homogeneous matter. For example: can ionization of certain dust particles, as a result of radiation absorption near the young sun where nuclear fusion processes have already begun (accompanied by intense radiation in the entire spectrum from UV to Gamma), can initiate point crystallization under electromagnetic forces - since nothing forces us to assume homogeneity Chemistry of the dust! It is certainly possible, and statistically even the large numbers are required, that there will be dust grains that are more or less inclined to accumulate electrostatic electricity, positive or negative in relation to other particles in their immediate environment. And even if, on average, significant volumes of dust remain neutral, crystallization nuclei will form at points, like snow crystals in a cloud.
I wonder how the seeds of dinosaurs got here.
They didn't ride an asteroid and won't survive on a comet.
They were brought here in an orderly manner, something like that
for a comfortable box.
I guess we will soon find evidence of that.
I wonder how the seeds of dinosaurs got here.
They didn't ride an asteroid and won't survive on a comet.
They were brought here in an orderly manner, something like that
for a comfortable box.
I guess we will soon find evidence of that.
Dear Yehuda, your questions do provoke a discussion since an object arriving with kinetic energy into the system can create collision reactions.
It is also possible that objects came from another solar system with minimal kinetic energy that would allow it (the object) to be a kind of 'nucleus' for the formation of a planet.
I assume that it will be a combination of local and external circumstances to the solar system that allowed the creation of these 'nuclei'
It doesn't seem to me that only the arrival of a rock from another solar system is the one that will cause the formation of a planet in our sun cave. In the orbit of the gas moving around the young sun, there is gas and dust that move a little faster and a little slower, so the planets that form will have no problem gathering the material into a large planet. It seems to me that a body that would arrive outside the solar system and cross the orbits of the newly formed planets could actually endanger them and prevent their formation.
Such rocks will participate in the formation of our planets but will not be a necessary condition for their formation
But maybe I'm wrong and don't forget that these are three in the morning thoughts that may not be true,
In general, it annoys me that a huge amount of dark matter that is known to be found everywhere and can be attached to all kinds of properties that can be engaged in the import and export of construction materials to the planets is simply being ignored
So please respond gently
Good night
Sabdarmish Yehuda
crazy!!