Planet Between Mars And Jupiter

[Moontanman]

It has been long said that Jupiter prevented a planet from forming between Mars and Jupiter, in fact some sources seem to indicate the Jupiter may be the reason Mars is so small. 

 

Thought experiment, if it was possible to move a planet between Mars and Jupiter, for the sake of this thought experiment lets say something about the mass of Earth. (Lets say Venus)

 

Would such a planet be stable in that orbit? (ignoring the asteroid impacts it would attract of course) 

[SwoopdeSwoop]

I presume it would be necessary that it end up much closer to Mars than Jupiter if you want the most stable orbit, but I don't see why not.

[Eclogite]

I do not think you can arrive at an intuitive conclusion. Implicit in your question is the belief that the solar system is currently stable, has been so since the end of the Late Bombardment Phase and will continue to be so until the sun's demise. This is not the case. The point is illustrated by these few examples from the literature.

 

The issue is well summarised here:

Batygin, K. et al  Chaotic Disintegration of the Inner Solar System The Astrophysical Journal 799-2 2015

 

On timescales that greatly exceed an orbital period, typical planetary orbits evolve in a stochastic yet stable fashion. On even longer timescales, however, planetary orbits can spontaneously transition from bounded to unbound chaotic states. Large-scale instabilities associated with such behavior appear to play a dominant role in shaping the architectures of planetary systems, including our own.

 

This is a specific instance: 

Laskar,J. Large Scale Chaos in the Solar system Astronomy and Astrophysics 287 L9-L12 1994

 

Numerous integrations of the solar system have been conducted, with very close initial conditions, totaling an integration time exceeding 100 Gyr. The motion of the large planets is always very regular. The chaotic zone explored by Venus and the Earth is moderate in size. The chaotic zone accessible to Mars is large and can lead to eccentricities greater than 0.2. The chaotic diffusion of Mercury is so large that its eccentricity can potentially reach values very close to 1, and ejection of this planet out of the solar system resulting from close encounter with Venus is possible in less than 3.5 Gyr.

 

This paper discusses in detail the determination of stability, explores specific cases and offers conclusions.

Davies, M.B. et al The Long-Term Dynamical Evolution of Planetary Systems arXiv:1311.6816 [astro-ph.EP] 2014

 

The possible instability of the terrestrial planets on a timescale of a few Gyr shows that the solar system has not yet finished evolving dynamically. Its overall structure can still change in the future, even if marginally within the remaining main-sequence lifetime of the Sun.

 

On this basis, while long term stability of such a planet's orbit is possible, it is by no means certain.

[Moontanman]

Ok, I see that I asked the question wrong, would such a planet be stable as the earth or at least for a few billion years as we see in he rest of the solar system? 

[Eclogite]

I think the papers I have quoted on provide an answer: possibly, perhaps even probably, but not necessarily.

[Moontanman]

Let me make sure we are on the same page, if we could move an earth sized planet into the orbit between Mars and Jupiter it would be at least as stable as the other inner planets? 

[Moontanman]

I think the papers I have quoted on provide an answer: possibly, perhaps even probably, but not necessarily.

 

 

Actually I couldn't access any but the last one and they all had little to nothing to do with the possible stability of placing a Earth sized planet in orbit between Mars and Jupiter. 

[Eclogite]

I don't know why you are having access problems. I checked the links and all were working for me.

 

The three papers have everything to do with the "possible stability of placing a Earth sized planet in orbit between Mars and Jupiter". They make the point that no orbit in the inner solar system is stable in the long term. There is no reason to suspect that an Earth sized planet between Mars and Jupiter would be a unique exception to this inherent instability.

 

There are many other similar papers detailing similar research and all reaching similar conclusions. I attempted to find research that offered a contrary view and was unsuccessful.

[CraigD]

Thought experiment, if it was possible to move a planet between Mars and Jupiter, for the sake of this thought experiment lets say something about the mass of Earth. (Lets say Venus)

 

Would such a planet be stable in that orbit? (ignoring the asteroid impacts it would attract of course)

Ok, I see that I asked the question wrong, would such a planet be stable as the earth or at least for a few billion years as we see in he rest of the solar system?

Good thought experimental question! :thumbs_up

 

I’d answer “yes”.

 

There actually is a planet, albeit a dwarf planet, in a nearly circular (eccentricity .075823) orbit as stable as the other inner planets, between the orbits of Mars (1.5237 AU from the Sun, eccentricity .093412) and Jupiter (5.2034, .048392) : Ceres, at 2.7675 AU.

 

Ceres is much smaller than the other inner planets, less than 1/360th the mass of Mercury. Most astronomers theorize that Ceres, in about its present orbit, formed at the same time as the other planets, but didn’t have as much protoplanetary material as the others, putting it below the critical threshold needed to “clear the neighborhood around its orbit” and raise it to the classification of (non-dwarf) planet. There’s about 2 times as much mass in Ceres’ orbital vicinity (the asteroid belt), as in Ceres itself, about 1/4th of it in the next 2 largest asteroids, Vesta and Palas, and another 3/4s in the 16 next largest asteroids – a pretty exact fit of the definition of an “uncleared neighborhood” the IAU had in mind when they came up with the planet vs. dwarf planet distinction back in 2006.

 

The most accepted theory is that Jupiter’s responsible for this, having swept a much larger orbital band than the smaller planets, overlapping Ceres’ and depriving Mars’ of so much that, despite its orbit being 1.5 times the circumference of Earths’, it only gathered 1/10th the mass.

 

Had Jupiter formed much further out, we can hypothesis that Mars and Ceres would have much larger masses, there’s be no asteroid belt, and there might be several more inner planets.

 

If you could, through magic or super-engineering, place an Earth-mass planet in a circular orbit between Mar’s and Jupiter’s, I can’t imagine any reason it wouldn’t stay there for billions of years.

[Eclogite]

If you could, through magic or super-engineering, place an Earth-mass planet in a circular orbit between Mar’s and Jupiter’s, I can’t imagine any reason it wouldn’t stay there for billions of years.

I sometimes feel I am talking to myself. Imagination, or intutition as I noted earlier, are irrelevant to the potential stability of such a planet. The research I have offered a tiny selection of reveals why it might not stay there for billions of years.

 

Yes, it is an interesting question, but the answer should be based upon sound research and not imagination.

[Moontanman]

I sometimes feel I am talking to myself. Imagination, or intutition as I noted earlier, are irrelevant to the potential stability of such a planet. The research I have offered a tiny selection of reveals why it might not stay there for billions of years.

 

Yes, it is an interesting question, but the answer should be based upon sound research and not imagination.

 

 

I couldn't read most of the links (behind pay walls or had to be printed) you provided and the one i could wasn't exactly clear on the question at hand. 

 

I know that orbit are not necessarily stable over huge stretches of time but from what we know the planets we now see have been relatively stable over giga years. 

 

I am thinking of technology that could move planets, not really impossible over long periods of time but of course that is not what i had in mind. I looks at newly discovered planetary system and see several planets orbiting within the orbital distance of our own mercury. 

 

I understand that Jupiter prevented a large planet from forming where we expected to find one back in the old days but if we could move a planet, in little or no significant time into orbit would Jupiter sling it out of the solar system pronto or would it be stable over giga years like the rest of the inner planets, of course my nest question is how long would it take for Venus to cool down at that distance but ultimately it's my story and the science is not as important as the story... 

[Eclogite]

I couldn't read most of the links (behind pay walls or had to be printed) you provided and the one i could wasn't exactly clear on the question at hand. 

There are three links. The first link is only to the abstract. I chose it because it is an excellent summary of the point I am trying to make. I tried to convey this by introducing it with the words: "The issue is well summarised here."

 

The second link takes you to the ADS abstract for the paper. However, if you select the third line down from the top of the page, Full Refereed Jounral Article (PDF/Postscript), it will give you access to the full paper.

 

I know that orbit are not necessarily stable over huge stretches of time but from what we know the planets we now see have been relatively stable over giga years

Yes, but the research I have quoted and the wealth of similar research, indicates that there is no assurance that they shall remain so for giga years into the future.

 

 

I am thinking of technology that could move planets, not really impossible over long periods of time but of course that is not what i had in mind.

That sentence appears to have two mutually exclusive clauses. Would you clarify?

 

 

I looks at newly discovered planetary system and see several planets orbiting within the orbital distance of our own mercury.

I suspect part of the impetus to investigate long term stability of orbits was in an effort to understand the dramatically different geometries of other planetary systems.

 

 

but if we could move a planet, in little or no significant time into orbit would Jupiter sling it out of the solar system pronto or would it be stable over giga years like the rest of the inner planets,

The act of moving the planet into position would create instabilities amongst the other terrestrial planets. If we could avoid this in some way then the orbit could be quasi-stable over giga years, but could also drop into an unstable condition in the same time frame. The point is that orbital mechanics in a multi-planet system are governed by chaos.

[sanctus]

Or see it this way: you are asking to solve an n-body problem (with n at least 4: mars, jupiter, new planet and sun), analytically we are able to solve only 2-body problems, 3-body in case of one body having a negligible mass compared to the others (eg. earth sun and moon).

[CraigD]

If you could, through magic or super-engineering, place an Earth-mass planet in a circular orbit between Mar’s and Jupiter’s, I can’t imagine any reason it wouldn’t stay there for billions of years.

I sometimes feel I am talking to myself. Imagination, or intutition as I noted earlier, are irrelevant to the potential stability of such a planet.

Rephrasing my previous summation, “If you could, through magic or super-engineering, place an Earth-mass planet in a circular orbit between Mar’s and Jupiter’s, Based on all the theory and literature I can recall, Including the work Laskar and Gastineau, I know of no more than 50% likely scenario in which it would not stay there for 5 billion years.”

 

The research I have offered a tiny selection of reveals why it might not stay there for billions of years.

Although I’ve read only the abstracts of those papers, in ”Chaotic diffusion in the Solar System” 22 Feb 2008 %5BarXiv%5D Jacques Laskar, I find

In (Laskar 1994), I showed the possibility of a very large increase of the eccentricity of Mercury, allowing for a close encounter or a collision with Venus. But in this work, there was no estimate of the probability for such an event to take place within a few Gyr. Here, such an estimate is given, by the extensive study of more than 1001 orbits. Indeed, it is found that the probability for Mercury’s eccentricity to exceed 0.6 within 5 Gyr is about 1 to 2 % which can be considered as a large value for such an important event.

This is important, because Laskar and Gastineau scenario for the destabilization of the inner planets’ orbits begins with Mercury’s orbit becoming very eccentric. (source, with references: this Wikipedia article section)

 

Although the 1 to 2 % probability of this happening within 5 billion years calculated by Laskar and Gastineau is “a large value for such an important event”, it implies a 98 to 99% probability that the inner planets will remain stable for the next 5 billion years.

 

I’m unaware of any calculations about the stability of thought-experimental planet with orbit between Mar’s and Jupiter’s carried out with the sophistication, precision, and long time scale of Laskar and Gastineau’s work, so conclude that such an orbit would be subject to the same destabilizing scenario they describe for the existing planets. The orbit of the dwarf planet Ceres, which is believed to be as old as the other inner planets’ (about 4.5 billion years), shows that such an orbit has been stable. Thus, I conclude that were an Earth-mass planet present in such an orbit, Laskar and Gastineau’s work indicates the probability that it would be stable for another 5 billion years to be 98 to 99%.

[Moontanman]

 

 

 

Eclgolite I appreciate your accuracy on this but to be honest I was simply looking for an assurance that such an orbit wasn't inherently unstable over short periods of time, as usual I asked the question wrong. I wanted to know if Jupiter's influence had just prevented a planet from forming there or if it would prevent a planet from orbiting there. 

 

I didn't know that our entire solar system is potentially unstable over long periods of time so i did learn something at least... 

[Eclogite]

Yes, I have the annoying habit of asking the question that was asked, not the one that was meant. But honestly, my name is not Sheldon.

[Moontanman]

Rephrasing my previous summation, “If you could, through magic or super-engineering, place an Earth-mass planet in a circular orbit between Mar’s and Jupiter’s, Based on all the theory and literature I can recall, Including the work Laskar and Gastineau, I know of no more than 50% likely scenario in which it would not stay there for 5 billion years.”

 

Although I’ve read only the abstracts of those papers, in ”Chaotic diffusion in the Solar System” 22 Feb 2008 %5BarXiv%5D Jacques Laskar, I find

In (Laskar 1994), I showed the possibility of a very large increase of the eccentricity of Mercury, allowing for a close encounter or a collision with Venus. But in this work, there was no estimate of the probability for such an event to take place within a few Gyr. Here, such an estimate is given, by the extensive study of more than 1001 orbits. Indeed, it is found that the probability for Mercury’s eccentricity to exceed 0.6 within 5 Gyr is about 1 to 2 % which can be considered as a large value for such an important event.

This is important, because Laskar and Gastineau scenario for the destabilization of the inner planets’ orbits begins with Mercury’s orbit becoming very eccentric. (source, with references: this Wikipedia article section)

 

Although the 1 to 2 % probability of this happening within 5 billion years calculated by Laskar and Gastineau is “a large value for such an important event”, it implies a 98 to 99% probability that the inner planets will remain stable for the next 5 billion years.

 

I’m unaware of any calculations about the stability of thought-experimental planet with orbit between Mar’s and Jupiter’s carried out with the sophistication, precision, and long time scale of Laskar and Gastineau’s work, so conclude that such an orbit would be subject to the same destabilizing scenario they describe for the existing planets. The orbit of the dwarf planet Ceres, which is believed to be as old as the other inner planets’ (about 4.5 billion years), shows that such an orbit has been stable. Thus, I conclude that were an Earth-mass planet present in such an orbit, Laskar and Gastineau’s work indicates the probability that it would be stable for another 5 billion years to be 98 to 99%.

 

 

 

Super technology is what I have in mind, anyone who could move planets around could make their orbits stable as well i am sure but i do appreciate everyone's efforts to school me on this. Now back to writing...