New theory on origin of the asteroid belt

September 14, 2017 by Bob Yirka report
The asteroid belt may be have started out empty and was populated by objects from across the Solar System. Credit: Sean Raymond, planetplanet.net

(Phys.org)—A pair of researchers with Université de Bordeaux has proposed a new theory to explain the origin of the asteroid belt. In their paper published in Science Advances, Sean Raymond and Andre Izidoro describe their theory and what they found when trying to model it.

The (sometimes referred to as the main asteroid belt) orbits between Mars and Jupiter. It consists of asteroids and minor forming a disk around the sun. It also serves as a sort of dividing line between the inner rocky planets and outer . Current theory suggests that the asteroid belt was once much more heavily populated, but the gravitational pull of Jupiter flung approximately 99 percent of its former material to other parts of the solar system or beyond. Astronomers also assumed that Jupiter's gravity prevented the material in the belt from coalescing into larger planets. In this new effort, the researchers propose a completely different explanation of the asteroid belt's origin—suggesting that the belt started out as an empty space and was subsequently filled by material flung from the inner and .

The researchers note that asteroids closer to the rocky planets (called S-type asteroids) tend to contain silicate, similar to the inner planets. By contrast, asteroids in the belt closer to the gas giants (called C-type asteroids) tend to contain more carbon, making them more like the gas giants. This, the researchers note, suggests that the asteroids actually came from the planets as they were forming—excess material was essentially kicked away into the asteroid belt, where it remains today.

To test their theory, the researchers created a model mimicking the early solar system, during which the belt starts out as empty. Running the model forward, they report, showed that it was possible that material from the other planets could have made its way to the belt, resulting in the disk observed today. They plan to continue their research to see if they can find more evidence for their theory, or for the conventional view.

Explore further: Astronomers identify oldest known asteroid family

More information: Sean N. Raymond et al. The empty primordial asteroid belt, Science Advances (2017). DOI: 10.1126/sciadv.1701138

Abstract
The asteroid belt contains less than a thousandth of Earth's mass and is radially segregated, with S-types dominating the inner belt and C-types the outer belt. It is generally assumed that the belt formed with far more mass and was later strongly depleted. We show that the present-day asteroid belt is consistent with having formed empty, without any planetesimals between Mars and Jupiter's present-day orbits. This is consistent with models in which drifting dust is concentrated into an isolated annulus of terrestrial planetesimals. Gravitational scattering during terrestrial planet formation causes radial spreading, transporting planetesimals from inside 1 to 1.5 astronomical units out to the belt. Several times the total current mass in S-types is implanted, with a preference for the inner main belt. C-types are implanted from the outside, as the giant planets' gas accretion destabilizes nearby planetesimals and injects a fraction into the asteroid belt, preferentially in the outer main belt. These implantation mechanisms are simple by-products of terrestrial and giant planet formation. The asteroid belt may thus represent a repository for planetary leftovers that accreted across the solar system but not in the belt itself.

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22 comments

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Chris_Reeve
1.6 / 5 (14) Sep 14, 2017
Article: "To test their theory, the researchers created a model mimicking the early solar system, during which the asteroid belt starts out as empty."

But, we see places like Valles Marineris, where there is an immense amount of missing matter.

https://en.wikipe..._of_Mars

"like Earth, Mars is a differentiated planet, meaning that it has a central core made up of metallic iron and nickel surrounded by a less dense, silicate mantle and crust."

The situation of the belt's formation is fundamentally historical, which means it's not well suited for modeling. And although it may impress their peers, their model is fundamentally conjectural ...

http://www.nature...-1.15480

"The discovery of thousands of star systems wildly different from our own has demolished ideas about how planets form."

What matters is their observation, not their suggestion for a cause.
Shootist
3.4 / 5 (10) Sep 14, 2017
But, we see places like Valles Marineris, where there is an immense amount of missing matter.


LOLOL

Regolith that was probably eroded out during the Tharsis uplift, by both lava and water, that obviously flowed east and north filling the 2000 km diameter Chryse Basin and an unnamed 1100 km diameter basin NE of Argyre and south of Aurorae Chaos, continuing its way north into Acidalia Planitia (aka, the putative Borealis Basin).
Maggnus
4.1 / 5 (13) Sep 14, 2017
But, we see places like Valles Marineris, where there is an immense amount of missing matter.
What the hell are you on about here Acolyte? Have you heard of "erosion"? https://en.wikipe.../Erosion Nothing is missing Acolyte.
What matters is their observation, not their suggestion for a cause.
Wow. Ok, Acolyte, given that magnetic reconnection is observed, then you agree it is real. So where does that leave your Cult? Don't they demand that magnetic reconnection cannot be? Or is this another example of you choosing when you close your eyes?
Maggnus
3.9 / 5 (11) Sep 14, 2017
Before someone else points it out, BTW, erosion is not the only force in play when it comes to the Valles. It is likely that a big part of the crustal deformation is related to the formation of the Tharsis bulge and the resulting rifting that likely arose during the formation this large crustal bulge.

No magical bolts from the blue required in any event.
baudrunner
2.2 / 5 (6) Sep 14, 2017
I still favor the worlds in collision theory, as it is much more plausible. The Vega solar system is similar to ours in that it also has an asteroid belt. It also appears to have a planet with a very unusual 2,000+ year orbit, which would lend credence to the collision theory. The jury is currently still out on the existence of Planet X.
Chris_Reeve
1.3 / 5 (14) Sep 14, 2017
From Plato's Dialogues at https://books.goo...pg=PA367

"Phaethon, the son of Helios, having yoked the steeds in his father's chariot, because he was not able to drive them in the path of his father, burned up all that was upon the earth, and was himself destroyed by a thunderbolt. Now, this has the form of a myth, but really signifies a declination of the bodies moving around the earth and in the heavens, and a great conflagration of things upon the earth recurring at long intervals of time ...

All of these stories, and ten thousand others which are still more wonderful, have a common origin; many of them have been lost in the lapse of ages, or exist only as fragments; but the origin of them is what no one has told"
dfjohnsonphd
3.9 / 5 (8) Sep 14, 2017
I thought this was about the asteroid belt, not Mars. Anyway, there are quite a number of "experts" who believe the gas giants actually formed much closer to the sun than they are now, and slowly migrated out to their present positions. This might contradict the above postulate of the belts formation. It all depends on when it formed.

Someone mentioned differentiation. I think there are some iron-nickel asteroids out there, and if that is true, the fracture of a small planet leading to the asteroid belt is not ruled out. Or, you must have such contributions from another fractured planet to get these. Maybe when earth was smacked by another body to form the moon this sent some of these metallic asteroids out to the belt. Still, hard to believe they would all wind up in a localized ring within the ecliptic if they came randomly from all the other planets. That they form this localized "belt" still suggests a busted up planet orbiting that position in the plane.
Chris_Reeve
1 / 5 (12) Sep 14, 2017
The bit about recurring conflagrations is very important: What Plato is describing is the repeated gravitational return of debris over periods of time (which cultures would of course learn to predict), yet as you already know, Plato had no idea what gravity was.

This could easily explain why cultures like the Aztec and Maya created calendars thousands of years ago.
Maggnus
3.3 / 5 (7) Sep 15, 2017
I still favor the worlds in collision theory, as it is much more plausible. The Vega solar system is similar to ours in that it also has an asteroid belt. It also appears to have a planet with a very unusual 2,000+ year orbit, which would lend credence to the collision theory. The jury is currently still out on the existence of Planet X.


No the jury came back years ago. They laughed and laughed. Jeezus baud quit running.
Maggnus
4 / 5 (8) Sep 15, 2017
FPhaethon, the son of Helios, having yoked the steeds in his father's chariot, because he was not able to drive them in the path of his father, burned up all that was upon the earth, and was himself destroyed by a thunderbolt. Now, this has the form of a myth, but really signifies a declination of the bodies moving around the earth and in the heavens, and a great conflagration of things upon the earth recurring at long intervals of time ...

All of these stories, and ten thousand others which are still more wonderful, have a common origin; many of them have been lost in the lapse of ages, or exist only as fragments; but the origin of them is what no one has told"


Oh wonderful, now the Acolyte promotes Hellenism. with a Velikovskyism twist - all religions are involved! You are a loon Chris.
Maggnus
4 / 5 (8) Sep 15, 2017
The bit about recurring conflagrations is very important: What Plato is describing is the repeated gravitational return of debris over periods of time (which cultures would of course learn to predict), yet as you already know, Plato had no idea what gravity was.

This could easily explain why cultures like the Aztec and Maya created calendars thousands of years ago.


Oh good god, it could also easily explain why vigins are offered to Christian crusaders bent on the re-subjection of the European masses. Gobblygook bullshit!!!!
Maggnus
4.2 / 5 (5) Sep 15, 2017
@dfjohnsonphd - yes there are certainly simulations that suggest the giants could have formed close to their host star and then migrated out to their current positions. There is also suggestions in the planetary models that some of the outer giants swapped places, and may even have kicked out one or more other planets during the early dance after their formation.

The fracturing of a small planet is not likely, although the possibility is not zero. Jupiter is the arbitrator, and its immense gravity is what likely prevented the formation of a planet in this area in any event.

Some light reading for you: http://hubblesite...ets-form
Chris_Reeve
1 / 5 (7) Sep 15, 2017
https://www.thund...eris.htm

"Valles Marineris is four times deeper than the Grand Canyon, and stretches for almost 3,000 miles across the face of Mars. Its presence has continued to baffle scientists. When the Mariner probes returned the first pictures of this continental-scale trench, many proposed catastrophic flooding as its cause. But scrutiny of later images revealed no outwash or debris field left by erosion, and no sign of ponding. Nor did the short 'tributaries', ENDING IN CLEANLY CUT ALCOVES, fit any reasonable profile of a drainage system."
barakn
3 / 5 (6) Sep 15, 2017
https://www.thund...eris.htm

"Valles Marineris is four times deeper than the Grand Canyon,

Wow, the links just keep coming.
Maggnus
3.4 / 5 (5) Sep 15, 2017
"*snip* Its presence has continued to baffle scientists. When the Mariner probes returned the first pictures of this continental-scale trench, many proposed catastrophic flooding as its cause. But scrutiny of later images revealed no outwash or debris field left by erosion, and no sign of ponding. Nor did the short 'tributaries', ENDING IN CLEANLY CUT ALCOVES, fit any reasonable profile of a drainage system."
Yea, back in 1976 the surprise of finding such a large canyon was totally unexpected and led to a number of investigations as to its cause. In the 40 years since then, much has been learned,. Although the Thunderdolts Cult of Magical Lightning doesn't think that science progresses, there is much more agreement about the likely origin now. Here is an example, and a simple google scholar search reveals some 5180 papers on the subject:

http://adsabs.har...28.1413T

rrwillsj
3 / 5 (4) Sep 15, 2017
It is obvious from many of the comments that people have little comprehension of how vast, 'vast' is. Or, how far,, 'far' is. Or, how long ago four billion years is.

The conclusions of this article, as I understand it, is trying to explain events that occurred billions of years ago. Perhaps new empirical evidence will be found to prove, disprove or modify these researcher''s hypothesis.

But it won't come from the corybantic commentators gibbering primitive stuporstitions.

During the early Solar System. As the planetesimals were still forming. "For every action, there is an equal & opposite reaction". A whole lot of debris was sent flying in all directions.

Another billion years or two, gravitational forces of the Sun & planets began to thin the jetsam & flotsam out. Organizing some of it into asteroidal clusters of the Belt and Trojan points.

My advocacy of this being a fractal crap-shoot of a universe, explains the extreme differences between star systems.
dfjohnsonphd
3.7 / 5 (3) Sep 15, 2017
@Maggnus, if the gas giants formed closer to the sun, than other rocky planets could have too and ended up somewhere further out. If a smashed planet(s) caused the asteroid belt, it need not have formed there. Since the data seem to confirm that the proto-earth was hit by a mars sized planet a long time ago to form the moon, there might have been a number of these rocky planets coalescing closer to the sun. The outward migration of the gas giants may have dragged some of these rockies into different orbits from where they were formed, with some ending in smash ups. Indeed, the proto-earth smash up might have been caused by the giants migrating out. Seems unilkely that two planets would form in nearly to same orbit (i.e. earth's). These planet draggings certainly would have happened early on. So a couple of planets crashing together to form the asteroid belt doesn't mean one or both of them formed where the current debris field is.

baudrunner
1 / 5 (1) Sep 15, 2017
No the jury came back years ago. They laughed and laughed. Jeezus baud quit running.
Hah! Think again.. https://phys.org/...sis.html
Maggnus
4 / 5 (4) Sep 15, 2017
dfjohnsonphd - while most of what you say is true, it is also the case that the constituents of the asteroid belt favours a situation where they were not a part of a single or two objects, The Bode law (http://www.astro....law.htm) also supports that the area where the asteroid belt is located is under too much gravitational interference from Jupiter for an object to have formed there. Keep in mind as well, that fully 2/3 of the mass of the asteroid belt is in one object, the dwarf planet Ceres, and if all of the mass of all of the objects in the asteroid belt somehow coalesced, the total mass would be less than our Moon.

Here's a little bit of information you may find interesting: https://physics.s...s-it-did
Maggnus
3 / 5 (4) Sep 15, 2017
No the jury came back years ago. They laughed and laughed. Jeezus baud quit running.
Hah! Think again.. https://phys.org/...sis.html

That's not Planet X baud, and the article doesn't give any credence to the worlds in collision hoopla in any event.
dfjohnsonphd
3 / 5 (2) Sep 15, 2017
Maggnus, Wiki calls this "Titius–Bode law". I had forgotten this postulate. It says that "bodies in some orbital systems, including the Sun's, orbit at semi-major axes in a function of planetary sequence" and that "each planet would be approximately twice as far from the Sun as the one before. The hypothesis correctly anticipated the orbits of Ceres (in the asteroid belt) and Uranus, but failed as a predictor of Neptune's orbit and has eventually been superseded as a theory of solar system formation." Also, "the large number of asteroids discovered in the belt removed Ceres from the list of planets" that support the "law". Sounds like it is off the table for most planetary formation theorists.

Wiki does imply you are correct about Jupiter preventing formation of a planet in that area, but that is under current conditions. From wiki "gravitational perturbations from Jupiter imbued the protoplanets with too much orbital energy for them to accrete into a planet...cont. next post
dfjohnsonphd
1 / 5 (1) Sep 15, 2017
From last post. still wiki quote.... "Collisions became too violent, and instead of fusing together, the planetesimals and most of the protoplanets shattered." But it also goes on to say that "99.9% of the asteroid belt's original mass was lost in the first 100 million years of the Solar System's history." This is a major loss, and further suggests a collision, at least to me. Not suggesting that Wiki has it all right, but the belt has been there for a very long time, and there is no telling today how it formed. Does not rule out a major collision between two larger planetary bodies long ago. Jupiter may prevent formation of a single body now, but Jupiter many not have been there during formation of the initial debris field. I suspect we will never be certain what happened out there a long time ago, but it seems highly unlikely that all that material simply appeared there in a relatively narrow zone WITHIN the ecliptic plane. What are the chances of that? I suggest zero.

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