Asteroids

Jupiter, Saturn Plowed Through Asteroids, Study Says

25 Feb , 2009

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When Mars and Jupiter migrated to their present orbits around 4 billion years ago, they left scars in the asteroids belt that are still visible today.

The evidence is unveiled in a new paper in this week’s issue of the journal Nature, by planetary scientists David Minton and Renu Malhotra from the University of Arizona in Tucson.  

The asteroid belt has long been known to harbor gaps, called Kirkwood gaps, in distinct locations. Some of these gaps correspond to unstable zones, where the modern-day gravitational influence of Jupiter and Saturn eject asteroids. But for the first time, Minton and Malhotra have noticed that some clearings don’t fit the bill.

“What we found was that many regions are depleted in asteroids relative to other regions, not just in the previously known Kirkwood gaps that are explained by the current planetary orbits,” Minton wrote in an email. In an editorial accompanying the paper, author Kevin Walsh added, “Qualitatively, it looks as if a snow plough were driven through the main asteroid belt, kicking out asteroids along the way and slowing to a stop at the inner edge of the belt.” 

Walsh hails from the Observatoire de la Côte d’Azur in France. In his News and Views piece, he explains that the known Kirkwood gaps, discovered by Daniel Kirkwood in 1867, “correspond to the location of orbital resonances with Jupiter — that is, of orbits whose periods are integer ratios of Jupiter’s orbital period.” For example, if an asteroid orbited the Sun three times for every time Jupiter did, it would be in a 3:1 orbital resonance with the planet, he wrote. Objects in resonance with a giant planet have inherently unstable orbits, and are likely to be ejected from the solar system. When planets migrated, astronomers believe objects in resonance with them also shifted, affecting different parts of the asteroid belt at different times. 

“Thus, if nothing has completely reshaped the asteroid belt since the planets settled into their current orbits, signatures of past planetary orbital migration may still remain,” Walsh wrote. And that’s exactly what Minton and Malhotra sought.

The asteroid belt easily gave up its secrets, showing the lingering evidence of planetary billiards on the inner edge of the asteroid belt and at the outer edge of each Kirkwood gap. The new finding, based on computer models, lends additional support to the theory that the giant planets — Jupiter, Saturn, Uranus and Neptune — formed twice as close to the sun as they are now and in a tighter configuration, and moved slowly outward. 

“The orbit of Pluto and other Kuiper belt objects that are trapped in [orbits that resonate] with Neptune can be explained by the outward migration of Neptune,” Minton and Malhotra write in the new study. “The exchange of angular momentum between planetesimals and the four giant planets caused the orbital migration of the giant planets until the outer planetesimal disk was depleted.”  Planetesimals are rocky and icy objects left over from planet formation.

“As Jupiter and Saturn migrated,” the authors continue, they wreaked havoc on the young asteroid belt, “exciting asteroids into terrestrial planet-crossing orbits, thereby greatly depleting the asteroid belt population and perhaps also causing a late heavy bombardment in the inner Solar System.”

The late heavy bombardment is proposed to have occurred about 3.9 billion years ago, or 600 million years after the birth of the Solar System, and it’s believed to account for many of the Moon’s oldest craters. Walsh said a reasonable next step, to corroborate the theory about the newly described clearings in the asteroid belt, is to link them chronologically with the bombardment.

LEAD PHOTO CAPTION: Artist’s depiction of the asteroid belt between Mars and Jupiter. Credit: David Minton and Renu Malhotra

Source: Nature


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Anaconda
Member
Anaconda
February 25, 2009 2:41 PM
Some notable quotes from the post: “Qualitatively, it looks as if a snow plough were driven through the main asteroid belt, kicking out asteroids along the way and slowing to a stop at the inner edge of the belt.” “When planets migrated, astronomers believe objects in resonance with them also shifted, affecting different parts of the asteroid belt at different times. ” The lead sentence in the post states: “When Mars and Jupiter migrated to their present orbits around 4 billion years ago…” What basis do scientists have for the timing of the planets’ “migrations”? Could it be that the “migrations” didn’t happen 4 billion years ago, but at some other time? And what possible dynamics would be… Read more »
David Minton
Guest
February 25, 2009 3:55 PM
Hi, I will try to answer your questions as best as I can. “What basis do scientists have for the timing of the planets’ “migrations”?” The timing is uncertain, but it is not likely to have occurred any later than about 3.8 billion years ago (4 billion is just rounding up). That is because 3.8 billion years ago is about the end of the period of heavy bombardment (or the so-called “late heavy bombardment,” or LHB) that is recorded in lunar rocks. While it is still debated as to whether planet migration can be linked to the LHB, certainly if the migration had happened any later than 3.8 billion years ago then the destabilized asteroids would have left… Read more »
robbi
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robbi
February 25, 2009 5:32 PM

Interesting theory-however, timeframes can be different periods depending on who does the research-therefore, I stay neutral in these ‘exchange of truths’!!

Salacious B. Crumb
Guest
Salacious B. Crumb
February 25, 2009 8:15 PM
Anaconda said; “And what possible dynamics would be generated by those planetary migrations. Answering theses questions… “Is it possible that those planetary migrations would effect the electromagnetic equilibrium of the interplanetary medium which science knows is of a electromagnetic nature being made up of plasma (the solar wind)?” NO “Could it be possible electrical discharges were released as a result of this electromagnetic disequilibrium?” NO “And what possoble scientific evidence could there be as a result of these hypothesized electrical discharges?” NONE Gravitational effects were (and are) the principle causes of such migrations, whose outcomes can be understood as to be caused by the “…exchange of angular momentum.” Gravitational perturbations of all planetary bodies has been well researched… Read more »
Total Science
Member
February 25, 2009 10:06 PM

Looks like Democritus and Velikovsky were 100% correct about worlds in collision. Shock and awe.

Salacious B. Crumb
Guest
Salacious B. Crumb
February 25, 2009 10:41 PM
OillsMastery said “Looks like Democritus and Velikovsky were 100% correct about worlds in collision.” Nice try, but total NOT true, especially in Velikovsky’s case. Immanuel Velikovsky is a proven out and out nutter, who thought that recent catastrophic collisions and close contacts occurred in Ancient times – especially towards both mythological and Biblical events. He even attempted to prove this evidence was retained in the geological record. Velikovsky also wrongly argued that electromagnetic effects play an important role in celestial mechanics. He was completely proven wrong in this assumption, and it has been shown that gravitational and perturbational effects are quite sufficiently precise to account for the general evolution of the Solar System. Furthermore, as this article eludes,… Read more »
drksky
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drksky
February 26, 2009 10:21 AM

Oh my….that one finally made my head explode. Someone please give me a rag to mop off my monitor.

Total Science
Member
February 26, 2009 3:46 AM
Salacious B. Crumb, “NOT true” Do you deny the fact that worlds collide? “Immanuel Velikovsky is a proven out and out nutter, who thought that recent catastrophic collisions and close contacts occurred in Ancient times – especially towards both mythological and Biblical events.” Are you saying that comets, meteor showers, and meteorite impacts are mythological events? “Velikovsky also wrongly argued that electromagnetic effects play an important role in celestial mechanics.” Why don’t you believe in electromagnetism? “He was completely proven wrong in this assumption, and it has been shown that gravitational and perturbational effects are quite sufficiently precise to account for the general evolution of the Solar System.” Gravitation causes the moon to fall away from the Earth… Read more »
Salacious B. Crumb
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Salacious B. Crumb
February 26, 2009 5:16 AM
OilIsMastery: Oh dear. Really how silly are you? I mean, how vacuous are you to state such a silly question as; “Why don’t you believe in electromagnetism?” I.e. How else did I communicate this post. Why does the sun hurt the eyes and how come the stars appear bright in the night sky? As to”Gravitation causes the moon to fall away from the Earth at 3.8 cm/year? Can you please explan how F = G x m^1m^2/r^2 accounts for the fact that the moon falls away from the Earth at 3.8 cm per year?” Very simply this is caused by conservation of angular momentum, where the Earth rotation is slowing due to tidal forces from the moon. As… Read more »
Total Science
Member
February 26, 2009 5:54 AM
Salacious B. Crumb, You didn’t answer the questions. Do you or do you not think that worlds collide? Do you or do you not think comets, meteor showers, and meteorite impacts are mythological? You say on the one hand electromagnetic effects play no important role in the universe and on the other hand you acknowledge electromagnetism is required for you to communicate. How do you reconcile your contradictory beliefs? “Very simply this is caused by conservation of angular momentum” So the conservation of angular momentum is anti-gravity? “the Earth rotation is slowing due to tidal forces from the moon.” “Currently, the moon is moving away from the Earth at such a great rate, that if you extrapolate back… Read more »
Salacious B. Crumb
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Salacious B. Crumb
February 26, 2009 6:28 AM

OilIsMastery said:
“So the conservation of angular momentum is anti-gravity?”
No, of course not.
If you don’t even understand that, then there is no one that can help you.
How about a far more modern and up to date quote;
“Some people in this world will always remain fruitcakes” – Salacious B. Crumb, Feb 2008

Total Science
Member
February 26, 2009 6:38 AM

Salacious,

6 years ago not modern enough for you?

Do you always believe the most recent fashions and fads in science? What do you do when the fad changes?

Salacious B. Crumb
Guest
Salacious B. Crumb
February 26, 2009 7:22 AM
Clear, 6 years ago it is not even close to current investigations. One of the current expert in this field is Prof. Bruce Runnegar, who is an Australian born palaeontology expert who currently works at the Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Whilst it is true that the current rate of increase in the lunar orbit at 3.82+/-0.07 cm per year, extrapolating the orbit backwards comes to the Roche limit some 1.6 billion years ago, there are other reasonable and logical explanations for the changes. (One of the biggest failures in these arguments in the currently observed changes are linear, which since have been proven to… Read more »
Total Science
Member
February 26, 2009 7:42 AM
“Clear, 6 years ago it is not even close to current investigations.” Does that mean you’re throwing out Newton and Einstein? Glad to hear it. “it is true that the current rate of increase in the lunar orbit at 3.82+/-0.07 cm per year, extrapolating the orbit backwards comes to the Roche limit some 1.6 billion years ago” I’m happy to hear you acknowledge reality. “Again the solution is via simple angular momentum.” But you already conceded that angular momentum is not anti-gravity. “Physical evidence for this appears in the geological record by sedimentary layering of tidalites.” They don’t mean jack. “Determination of absolute ‘Earth-Moon’ distances and Earth’s paleorotational parameters in the distant geological past from tidal rhytmite, however,… Read more »
Amber K. Muir
Guest
Amber K. Muir
February 26, 2009 7:50 AM

OilIsMastery Said:
“How do you reconcile your contradictory beliefs?”
followed by
“So the conservation of angular momentum is anti-gravity?”

Even I learnt about angular momentum in Junior High. I know it is not anti-gravity.
Salacious in the end might in fact be right about you after all.

Amber K. Muir
Guest
Amber K. Muir
February 26, 2009 7:58 AM

OilIsMastery. Whose being a naughty little boy now?
Four months ago probably feels like an eternity to you.
In my view perhaps we ought to get out the turpentine.
Feeling very sorry for you mate.

David Minton
Guest
February 26, 2009 8:33 AM
Well, it’s certainly been interesting to see such a spirited discussion inspired by this work! I ought to mention that this work really has absolutely nothing in common with Velikovsky, aside from the idea that some planets moved in the past, which is a trivial similarity. Now, I know some people like to point out that scientists seem to change their minds quite a bit, so today’s ideas might turn out to be wrong. Well, yes, but only to a point. It’s important to keep in mind that scientific theories don’t change arbitrarily. Any new theory *must* be compatible with the preponderance of evidence, as it is. To take Velikovsky as an example, his ideas about planetary motion… Read more »
Arcturus
Guest
Arcturus
February 26, 2009 8:33 AM

OIlIsMastery, can you please explain how F = k*q1*q2/r^2 accounts for the fact that the electron doesn’t crash on to the nucleus of an atom?

Total Science
Member
February 26, 2009 8:48 AM
David, In response to: “Now, I know some people like to point out that scientists seem to change their minds quite a bit, so today’s ideas might turn out to be wrong. Well, yes, but only to a point.” “The history of science demonstrates, however, that the scientific truths of yesterday are often viewed as misconceptions, and, conversely, that ideas rejected in the past may now be considered true. History is littered with the discarded beliefs of yesteryear, and the present is populated by epistemic corrections. This realization leads us to the central problem of the history and philosophy of science: How are we to evaluate contemporary sciences’s claims to truth given the perishability of past scientific knowledge?… Read more »
Total Science
Member
February 26, 2009 8:54 AM

Arcturus,

“OIlIsMastery, can you please explain how F = k*q1*q2/r^2 accounts for the fact that the electron doesn’t crash on to the nucleus of an atom?”

Sure.

It doesn’t.

The mathematical proofs of Newton are totally erroneus. Quantum gravity is a myth just as the so-called “Law of Universal Gravitation.”

The alleged “Law of Universal Gravitation” was empirically falsified on August 22nd 1963 when Joseph A. Walker first experienced zero g. So much for universal gravitation.

“An atom differs from the solar system by the fact that it is not gravitation that makes the electrons go round the nucleus, but electricity.” — Bertrand Russell, physicist/philosopher, 1924

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