Halo of Oligarchs

[zazaban]

I've just read about a hypothesis that has quite captured my imagination. It suggests that dozens of earth-sized protoplanets from the formation of the solar system may have been flung out to about 1,000 to 10,000 AU, where they exist still as a giant halo of dead husks of planets. I find this idea extremely interesting. It gives quite a majestic image. All these cold, desolate rocks floating out far from the sun, quietly orbiting away from all activity in their own graveyard. Perhaps a goldmine of resources for grave robbers from Earth hundreds of years from now.

I'm aware this is a crappy opening post for a topic, but I'm extremely tired, and really into this.

 

[UFmbutler]

I guess it's possible in some alternate version of the solar system, but what is there to support this idea? Why would so many Earth-sized planets get flung out(what flings them out? they would have to be scattered away by something), while planets such as Mars, Venus, our own Earth, etc stayed put? I would think having so many large rocky bodies in the inner solar system would lead to a very unstable system, and we just don't see that. I also think we would be able to detect these planets, considering we can find minor planets(Sedna) out to distances of ~1000 AU.

So while it may sound interesting as an idea, it sounds more like the plot to some scifi novel more than a real scientific hypothesis. There are just too many problems with it and no evidence to support it.

 

[MeteorWayne]

This sounds like the Oort Cloud, except there is no evidence that there are earth sized objects out there, and the distance is greater. If you consider asteroids and comets protoplanets, then that would be a fair description. If there were earth sized objects, we would probably have detected at least a few through gravitational lensing.

 

[SpaceTas]

UFmButler

I've heard of this idea, but wasn't aware it had a name. Some planet formation simulations, have lots of planets being formed in all sorts of orbit. These interact gravitationally, with many close encounters. Three body interaction in particular can send one object flying off. So if these simulations are right there should be a population of free floating planets unattached to any star, or maybe in halos around the star; a bit different from the Oort cloud as left over planetisimals.

There have been a few claims for free floating planets. But no sign of any large (Earth plus objects) well beyond the Kuiper belt. The Kuiper belt = trans Neptunian Objects, Pluto etc. It does appear to have an outer edge.

You have also hit upon an objection to the whole notion of a highly unstable ealy solar system; why is it so sane now? Oh back calculations show that major planetary orbits have been stable for at least a billion years!

 

[MeteorWayne]

The formation of planet sized bodies at the distance of the Oort cloud is extremely unlikely due to the low density of matter there. The formation of the cloud, as currently understood, is that it consists of objects that formed in the inner solar system, and were ejected to that location by interactions with the major planets, primarily Jupiter. Whether that is correct or not remains to be seen.

 

[silylene]

If the Oligarchs did exist, shouldn't we have detected at least one of them in the ongoing long-term stellar occultation studies of the Magellanic Clouds?

 

[xXTheOneRavenXx]

That would be really cool if such objects were found. Not only for their amount of physical resources, but I'm sure they would be quite a useful tool in understanding the very happenings when the solar system was young, especially if they did migrate from the inner solar system to their current location.

 

[MeteorWayne]

I don't know about the physical resources thing...at a light year away, they would not exactly be accessable

The Voyagers and New Horizons won't reach that distance for centuries, and they're the fastest things we've ever shipped outward.

 

[SpaceTas]

My earlier post should have pointed out these simulations are for the inside the orbit of roughly Neptune.

 

[gacia]

I don't know about the physical resources thing...at a light year away, they would not exactly be accessable

The Voyagers and New Horizons won't reach that distance for centuries, and they're the fastest things we've ever shipped outward.

For all we know, they might just become accessible.

 

[kelvinzero]

Would we really have detected them by now if there were only dozens? According to wiki we didnt find Eris until 2005. Eris is nothing to sneeze at with a diameter of about 2500km, and about 20 to 200 times closer than the distances discussed here.

 

[xXTheOneRavenXx]

I know it will be a long time before we could reach that distance. However when we are able to, the resources of such objects would amount to more then just for fuels, etc... My guess is if these objects do exist and did migrate from the inner solar system that their surfaces would be littered with debris from the early solar system since it is believed to have been a very chaotic time. This would be like looking back in time and providing us with very valuable information.

 

[zazaban]

Hm, interesting. I suppose they would be an excellent place for certain kinds of scientific tests that require both incredible cold and solid land as well.

I just like obscure hypothesis like this, ones that aren't totally crazy.

 

[3488]

My earlier post should have pointed out these simulations are for the inside the orbit of roughly Neptune.

Hi SpaceTas,

I would imagine that by now any Earth sized KBOs inside the orbit of Neptune would have been found long before now.

Pluto was discovered whilst still well outside Neptune's orbit & Eris a slightly larger, though somewhat more massive KBO than Pluto has been found well beyond Neptune's orbit. Both Pluto & Eris are considerably smaller than our Moon.

As Wayne says, there is much speculation that the infant Jupiter & Saturn may have flung out ice bodies to the hypothetical Oort Cloud.

The 214 KM wide Saturn moon Phoebe may be one such body that got captured by Saturn instead.

Whether or not any of them could have grown to be Earth sized is open to conjecture at best. Moon sized, Mercury sized or Mars sized are more likely, but even then I suspect even these would be on the large sized.

That's my tuppence worth. :mrgreen:

Andrew Brown.

 

[thebigcat]

I see nothing to suggest that there couldn't be an object of at least Earth mass out in the Oort cloud which we have not yet discovered. It would at least provide an explanation for those long-period comets...Something has perturbed them from their orbits, they don't just fall inward on their own.

To find an object like that using gravitational lensing would be a daunting task. That far out it's orbital period would be tens of thousands of years. It would require comparing photographs taken years apart, perhaps decades, when the Earth is on the same point in it's orbit to eliminate parallax. And even then, the object might not be orbiting on the ecliptic. Comets come at us from all directions. We might have to search the entire sky to find this "Oligarch". Or "Oligarchs" as the case might be.

It's an interesting suggestion, at least.

 

[SpaceTas]

Hi 3488,

sorry I didn't mean to imply there should be any undiscovered earth mass objects inside the orbit of Neptune. The comment was to point out the these simulations of planet formation with ejection of proto-planets say nothing about the Oort cloud.

 

[MeteorWayne]

Actually, yes they do. The models predict that most of the material in the Oort cloud did not form in place (matter was too sparse to form large objects, but rather were ejected to that location from the inner solar system.

 

[ZenGalacticore]

I don't know about the physical resources thing...at a light year away, they would not exactly be accessable

The Voyagers and New Horizons won't reach that distance for centuries, and they're the fastest things we've ever shipped outward.

Well that's one of the interesting ironies about the two Voyager spacecraft. They'll be entering interstellar space some time in the next couple of decades or so, but we have every reason to believe that we'll have much faster craft in fifty to a hundred or so years that will be able to overtake them.

So if we have second thoughts about "crying out in the jungle and letting our presence be known", as Hawking referred to, then we can retrieve them at some future time if we decide to do so. After all, if their trajectories were pointing them to any nearby star systems (which they are not), it would take them 40,000 years just to reach Alpha Centauri.