Interesting article on the early Solar System

[Odin2005]

http://www.psrd.hawaii.edu/Aug06/cataclysmDynamics.html




Red = Jupiter
Orange = Saturn
Purple = Uranus
Blue = Neptune

Wandering Gas Giants and Lunar Bombardment

There may have been a dramatic event early in the history of the Solar System--the intense bombardment of the inner planets and the Moon by planetesimals during a narrow interval between 3.92 and 3.85 billion years ago, called the late heavy bombardment, but also nicknamed the lunar cataclysm. The evidence for this event comes from Apollo lunar samples and lunar meteorites. While not proven, it makes for an interesting working hypothesis. If correct, what caused it to happen?

A group of physicists from the Observatoire de la Côte d'Azur (Nice, France), GEA/OV/Universidade Federal do Rio de Janeiro and Observatório Nacional/MTC (Rio de Janeiro, Brazil), and the Southwest Research Institute (Boulder, Colorado) conducted a series of studies of the dynamics of the early Solar System. Alessandro Morbidelli, Kleomenis Tsiganis, Rodney Gomes, and Harold Levison simulated the migration of Saturn and Jupiter. When the orbits of these giant planets reached the special condition of Saturn making one trip around the Sun for every two trips by Jupiter (called the 1:2 resonance), violent gravitational shoves made the orbits of Neptune and Uranus unstable, causing them to migrate rapidly and scatter countless planetesimals throughout the Solar System. This dramatic event could have happened in a short interval, anywhere from 200 million years to a billion years after planet formation, causing the lunar cataclysm, which would have affected all the inner planets.

:wow: @ Neptune

[Bill McBlueState]

1. whoa!

That's really cool about Neptune.

[1620rock]

2. Wow! All of this happened in just 6000 years?....

:sarcasm:

[DRoseDARs]

7. Well, there's a reason that the animation runs sooo fast... n/t

;)

[NNadir]

3. That is interesting. Thanks.

[Dead_Parrot]

4. Whoa. Too cool... nt

[Ediacara]

5. Sorry to harp on this "clear their neighborhood" silliness

but does this mean that for 100 million years the gas giants stopped being planets because there was so much crap flying around?

[DRoseDARs]

6. That's not what they're saying at all. Not sure where you're getting that

:shrug:

[mccoyn]

9. The new definition of planets.

A planet has to clear its orbital neighborhood of objects to be considered a planet.

[Ediacara]

12. I was being snarky concerning the IAU's new planet definition

and the extremely vague requirement that they must "clear their neighborhood."

[mainegreen]

8. Evidently.

:P

[Bill McBlueState]

10. well, sort of

When there was still "so much crap flying around," none of the planets had cleared their neighborhoods. I would call them protoplanets at this stage.

The objects that did successfully clear their neighborhoods became today's planets.

[Ediacara]

11. Obviously, I should read the paper

but from their model, it appears as though the gas giants had cleared their neighborhood for a period of time before Neptune's ejection, but then during that 100MY window, they had to re-clear their neighborhood, and would in all snark, not be planets.

I understand what is implied by "clear their neighborhood" but I agree with your previous posts that they should have just written "gravitationallly dominant in its orbit," or something like that.

[Bill McBlueState]

13. you've got a point

Using "protoplanet" to describe fully-formed planets that are undergoing a second period of neighborhood clearing is a bit of a stretch.

Okay ... enough about this! So trivial... but I can't... stop... posting about it! :crazy: