Notice this thing has an eccentricity of 0.3, something with the eccentricity of
0.3 something major access of 15 means that it's uphilling.
That's farthest away from the sun is more like 20 AU's.
So it's an invading all the way to out here.
It goes up to here now.
And eccentricity of 0.5 and 20 AU, that means,
it's uphilling all the way out here.
There's no way these objects can survive while these very eccentric
objects are making their way through there.
Plus, these two objects are crossing their orbits, it's crazy.
The eccentricities of the Kuiper belt get very quickly raised up, and
that whole Kuiper belt gets essentially destroyed.
In the meantime, the eccentricities of Uranus and Neptune,
by scattering all these things out of the solar system, or into Jupiter and Saturn.
The eccentricities that Uranus and Neptune start to drop,
the inclinations start to drop, the simulation doesn't continue
on to where they finally drop down to their present values.
But they will.
They have a lot of material to scatter out.
Dynamical friction is very powerful.
They will drop back down and as they drop down to their present locations and
present values they will eject everything from the solar system except for
things that are in these mean motion resonances or
things that are far enough away that they're not affected.
And we will end up with something that looks an awful lot like the Kuiper belt.
Okay, so this, maybe, doesn't seem that much different.
Jupiter, Saturn, Uranus, Neptune form in close, and they either smoothly push their
way out, or Uranus and Neptune get tossed out there, and eject things.
These are, in fact, however, profoundly different.
It's a difference between a very smooth migration of all the planets and
a very orderly reshaping of the outer solar system versus a sudden dynamical
explosion which shakes the entire solar system ejects stuff all over the place.
Now, this sudden shaking of the solar system doesn't happen
necessarily right at the very beginning of the solar system.
It happens whenever Jupiter and Saturn cross that 2:1 resonance.
So, it could be time,
we don't know when it happened if it happened, but it could've happened
something like 600 million years after the formation of the solar system.
Why do I say 600 million years to the formation of the solar system?
Well, that's a special time.
Remember there are all the material in the outer part of the solar system,
all that shaking caused it to be
spewing all over the solar system including the inter solar system,
including the moon, including what could be the late heavy bombardment.
These Kuiper belt objects from further out
could have been the things that hit the moon for the late heavy bombardment.
Plus, Jupiter and Saturn becoming very eccentric would
dislodge many of the asteroids in the asteroid belt.
They would hit the Earth, they would hit the moon, they would hit Mars.
This could be an explanation not just for
that mundane sounding thing of the eccentricities of the planets but for
this, again, profound thing, this late heavy bombardment.
There are few more things of this model predicts or
explains depending on how you want to look at it.
And one of them is the presence of
two of the small body populations we haven't talked much about.
One of them is the irregular satellites.
Remember that Jupiter, of course, has couple of regular satellites.
Io, Europa, Ganymede, Callisto, pretty close to Jupiter, pretty big.
Regular we call them because they are nice regular circular orbits around Jupiter.
But it has a whole host of irregular satellites, really far away,
eccentric orbits.
Going all over the place, tiny things.
And these have always been understood to be captured.
It was just never clear where they were captured or when they were captured,
or what sorts of objects they were before they were captured.
In this Nice model, these things have to be Kuiper belt objects.
They have to have come from the outer part of the disk and
as this big instability is going on, well the Kuiper belt is the most massive,
small body population at the beginning of the solar system.
And so when there are millions and millions
of objects flying around the solar system, they are mostly capable objects.
So what is their most link to be captured, mostly Kuiper belt objects.
One of the interesting questions to find out is
if we could look at some of these small, irregular satellites,
are we going to find out do they look just like a Kuiper belt object would look?
I'm actually trying to do that project right now and
answer some of these questions about some of these irregular satellites.
There's a second population that we haven't talked much about but
it's another population of what are called asteroids.
And these are trojan asteroids.
These are asteroids that are on an orbit either 60 degrees in front of Jupiter or
60 degrees behind Jupiter.
And sort of like the regular satellites these had to have been captured
into this peculiar orbit.
They're stable in that orbit because the forces from the sun, and
from Jupiter cancel out and let them be very stable right there.
So they will stay there forever.
And the question is how did they get there and, where did they come from.
For years it was thought they had come from the asteroid belt in here, and
somehow migrated their way out to there and become part of the Trojan population.
So if we could look at Trojan asteroids in detail we would find out that they
are just like the outer parts of the asteroid belt.
The Nice model, on the other hand,
proposes that these things came from the Kuiper belt.
In that same period when everything was flying around everywhere Kuiper belt
objects were flying everywhere and
they would have been the things that have been captured in.
If we could get to these Trojans and see what they're made out of, and
see that they're made out of the same materials as Kuiper belt objects.
See that they're made out of materials that we only expect to form in this
outer part of the solar system,
I think we will have answered an incredibly profound question.
Because, remember this is Jupiter, there's Saturn, there's Uranus, there's Neptune.
There are a lot of giant planets between the Kuiper's belt and the Trojans.
There's no reasonable way that we could get Kuiper belt objects in here to
the Trojans if we had smooth migration of all these planets inward and outward.
The only way we can get these outer parts of the disk into the inner part of a disk
is through this one sort of dynamical explosion.
So, in some ways I believe that these Trojan asteroids are the key
to understanding if this amazing story that the Nice model tries were opposed.
This amazing story is really true.
How would you do it.
Well, we have some ideas.
NASA is very interested in sending spacecraft to Trojan asteroid.
I think this would be a really good idea as long as it doesn't have a lame acronym.
And we have some tricks.
We're trying to use telescope on the ground to try to connect
to see if we can find similarity between these objects.
In these subjects, and best I can tell you is that this is what I worked on earlier
this week and you have to stay tuned, I'm going to let you know.