Skip to comments.Migrating planets caused meteor storm
Posted on 03/26/2013 3:29:15 PM PDT by LibWhacker
Migrating planets caused meteor storm
Meteor storm Migration of giant gas planets such as Jupiter created the biggest meteor storm in our solar system's history, according to a new study.
The research in the journal Nature Geoscience paints the clearest picture yet of the causes of the Late Heavy Bombardment, a cosmic tempest 3.9 billion years ago, which shaped the solar system we have today.
Scientists have long hypothesised the bombardment was caused by planetary migration, as Jupiter and Saturn moved closer in towards the Sun, while Neptune and Uranus moved further out from where they formed.
The gravitational effects caused by these migrations flung large numbers of meteors towards the inner solar system, where they collided with the terrestrial planets, including the Earth and Moon.
They are also credited with sending the asteroids and comets into the orbits they have today.
The new paper by researchers including lead author Dr Simone Marchi from the Southwest Research Institute, in Boulder Colorado, supports this hypothesis based on a new study of Apollo 16 Moon rocks, and two major types of meteoroids.
These include high-metal H-chondrites which make up almost half of all meteors and meteorites believed to have originated on the main belt asteroid Vesta.
Marchi and colleagues used argon isotope readings to determine when the impacts that created the samples occurred.
Their models and computer simulations indicate a period of intense meteor bombardment thoughout the inner solar system between 3.4 and 4.1 billion years ago, coinciding with the Late Heavy Bombardment.
The argon readings also indicate that the meteor samples could only have resulted from high velocity impacts in excess of 10 kilometres per second.
Support for the Late Heavy Bombardment theory had waned after revelations that some lunar zircons and breccias caused by impacts are older than four billion years, and some 3.9-billion-year crater impact dates were all derived from a single large impact site known as the Imbrium Basin.
These findings raised the prospect of an alternative idea that the dates represent impacts from a smoothly declining bombardment of leftover planetary construction material.
But planetary scientist Dr Simon O'Toole from the Australian Astronomical Observatory says the new paper addresses doubts about planetary migration in our solar system.
"The new argon calculations provide an important result filling holes in existing planetary migration models for the Late Heavy Bombardment theory," says O'Toole.
"Previous models predict only low velocity impacts under five kilometres per second occurring in the asteroid belt," says O'Toole.
"Higher velocities would have placed these asteroids on planet crossing orbits, crashing into planets and quickly emptying out the asteroid belt."
However the gravitational influence of the migrating planets changed the orbits of the asteroids sending them far above and below the orbital plane of solar system reducing the risks of a planetary collision, says O'Toole.
"[The study] provides us with a good foundation stone for a better understanding of the early solar system and how it got to look the way it does now."
There’s an episode of “The Universe” about this theory that’s pretty good.
I’m sure right now there’s some RINO in Congress thinking that they should write up an amnesty for undocumented planetary immigrants.
That would be cool if it turned out Immanuel Velikovsky was right after all.
I’ve never read him, but I have a feeling they’d still rush to pick him apart, despite these “new” theories.
I think I’ve seen it. Is it a couple of years old? Anyhoo, love those Sci Channel programs! The only one I’ve ever been able to get my wife interested in was Brian Cox’s “Wonders of the Universe.” She really like those and was properly awed. Don’t look a gift horse in the mouth!
Very cool, thx! I have a feeling I’m going to be wasting even more time on the computer for the next few days than usual!
No way! Meteor showers are caused by anticipatory CO2 levels at least 3.8 billion years in the future.
More likely that Tom Van Flandern was right ...
Cool, I bookmarked it. Have you considered enhancing the code to show 3D orbitals (rather than all in the same ecliptic)?
Here’s one I used to play with.
But I like yours even better.
Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits
New insights into composition of giant planets
Giant planet ejected from the solar system
When straying Jupiter went on the pull
Doesn’t explain why one of those planets is rotating on its side......
That’s a mystery which may defy solution until someone figures out time travel. I mean, we’re all time travellers, but time travel in the opposite direction. :’) The reason for the lack of consensus on the Uranian tipped axis is that the Uranian moon system is the most normal of any in the Solar System, at least among the four known gas giants. Almost any mechanism devised to explain Uranus’ tipped axis trips over the normality of the Uranian moons.
If there’s little or no core in Uranus (it’s the second least dense of the planets, Saturn’s the least dense) it’s at least possible that a slow migration of the planet’s axis, analogous to a spinning top, and due to an irregularly shaped rocky core (or a split core, that is, *two* rocky cores), may account for the change in the axial tilt without screwing too much with the moons. And of course, we’re only seeing the moons now — if they’re ejections or captures by Uranus, the migration of the Uranian axis may have been what normalized them to their current state.
Van Flandern’s EPH might be looked upon as one explanatory model, except for the fact that there’s no explanation for the explanation. :’)
Uranus and Neptune - Origin
Sky&Tel 99, 24 (2000)
These two ice-giant planets would take longer than the age of the solar system to form at their present distances from the Sun. So they must have formed closer and migrated outward. The suggested process is gravitational encounters with Jupiter and Saturn, and subsequent chaotic variations due to interactions with small planetesimals, before their orbits stabilized in their current locations. No gas drag effect of the solar nebula was considered.
Tom Van Flandern comments:
This violates the Poincare theorem forbidding secular perturbations in semi-major axis, and conservation of angular momentum, among other problems. If only Velikovsky had known how easy it was to get a planet into a circular orbit! :-)
Uranus and Neptune - Formation of rings by collisional fragmentation
. JGR Planets 105, 17,589-17,599 (2000)
The narrow Uranian and Neptunian rings cannot be older than 600 million years because of collisional disruption from comets and Kuiper belt asteroids. They are probably formed by collisions with small satellites.
Tom Van Flandern comments:
One wonders why those collisions did not occur within the solar systemâs first 600 million years, unless these colliding bodies originated more recently themselves from exploded planets.
Everybody knows SUVs cause meteor showers....
The other model (which I’d posted before, somewhere, maybe on FR) for the axial tip is the arrival, from the direction of one of the original poles, of the mass of liquid that makes up most of Uranus today; the previous mass of the planet might have been smaller, currently (it sez here) it is about 14 1/2 times the mass of Earth; its original density would have been higher. Arrival of this mass would have to have been sufficient to change the axis after some period of instability.
The arriving mass might have been what is now the rocky core, or (you guessed it) the secondary rocky core, producing the irregular mass distribution which has altered the axis of rotation until it’s nearly in the ecliptic. This is a bit cleaner, and more probable than the arrival of a long train of water of at planetary mass probably exceeding the mass of the Earth.
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