Marauding Gas Giants

[Tomjo59]

I’ve watched the latest program of Prof Cox’s ‘The Planets’ series, about Jupiter.

He states that computer models of the solar system’s formation  indicate that Jupiter migrated towards the inner solar system quite early in its history, explaining several ‘odd’ features, such as the small size of Mars, lack of ‘Super Earth’s’ etc. Jupiter then migrated outwards again, apparently.

However, it didn’t seem clear from his description exactly WHY Jupiter should have performed these migrations.

Did I miss something?

[maw lod qan]

Did it migrate in a regular shaped orbit around the sun? Or in an elipitcal shaped orbit, similar to a comet?

The forces either way would be incredible for it to eventually end up so distant from the sun in the orbit it's in now.

[Tomjo59]

4 minutes ago, maw lod qan said:

Did it migrate in a regular shaped orbit around the sun? Or in an elipitcal shaped orbit, similar to a comet?

The forces either way would be incredible for it to eventually end up so distant from the sun in the orbit it's in now.

A fair question.

I can’t imagine it would have had a ‘comet-like’ orbit, and I assume that a change of a more normal elliptical orbit would have to be related to a change in the overall angular momentum of the solar system, especially the relation between the Sun and Jupiter.

[andrew s]

If you Google " early solar system simulations" you can find several you tube clips and some interesting papers on this topic.

Regards Andrew 

[maw lod qan]

If I remember correctly, Jupiter being so large, it is the only planet where the central gravitational  point between it and the Sun, is outside the Sun.

We view it and know it's big, but to be large enough for everything in the solar system, except the Sun, to fit inside it, takes it from big to enormous. 

[Tomjo59]

21 hours ago, andrew s said:

If you Google " early solar system simulations" you can find several you tube clips and some interesting papers on this topic.

Regards Andrew 

Yes, I’ve seen those, and theories such as the ‘Grand Tack’ seem very speculative (some might even say contrived), and are not without their problems (see https://en.m.wikipedia.org/wiki/Grand_tack_hypothesis, for example).

I suppose that is how science progresses though. I suspect that the uncertainty and complexity of the theory is why Cox didn’t really mention the mechanism by which the migrations took place.

[DaveS]

He was a bit "handwaving" about how the resonance between Jupiter and Saturn caused both to move outward, but that's because orbital mechanics with more than two bodies makes solving Schrödinger's wave equation look like primary school "sums".

[Demonperformer]

There may be more to it than he said, but his constant "Jupiter did this" and "Jupiter did that" all seemed mighty speculative to me. Why should the impact that exterminated the dinosaurs have been caused by Jupiter? There are earth-crossing objects of similar size. Why not just one of those? Wouldn't that be the simplest solution? And doesn't Occams Razor require us to accept the simplest solution?

[kirkster501]

The Planets is mean to be entertainment for the masses.  I think a considerable degree of "artistic license" has been used in this program's creation.  The narrative jumps all over the place and statements made as fact that are, two minutes later, said are "what we think happened".   Ten minutes of material last 50 minutes with panning shots of BC walking around and utterly irrelevant scenery and location shots baked into the show.

Still, entertaining nonetheless if not a bit monotonous.    6/10.

[Paul73]

At least he was walking, rather than wistfully gazing into the distance wondering what to spend his fee on.

Overall, I enjoyed it, but the glacial pace left me falling asleep!

Paul

[Demonperformer]

Caught the latest episode last evening. So, according to one of his early statements, Saturn is "far beyond the sun" ... in relation to what? The earth? Not at the moment - it is in the opposite direction.  Did he maybe mean to say "far away from the sun"?

[tomato]

I must be turning into a grumpy old man because nowadays most TV documentaries do seem to make 10 minutes of footage last an hour by recycling the same content. I remember the Horizon and Equinox programmes in the 80’s and 90’s being so superior, maybe it’s the passage of time.

[Gina]

I've found the same!

[Demonperformer]

6 hours ago, tomato said:

I remember the Horizon and Equinox programmes in the 80’s and 90’s being so superior

they were. i've still got a load of them on disc and revisit them on occasion.

[MarsG76]

maybe it was looking for a new home, thinking that the grass is greener on the other side.... 😉

 

[Tomjo59]

10 hours ago, tomato said:

I must be turning into a grumpy old man because nowadays most TV documentaries do seem to make 10 minutes of footage last an hour by recycling the same content. I remember the Horizon and Equinox programmes in the 80’s and 90’s being so superior, maybe it’s the passage of time.

I think it’s called ‘dumbing down’.

Seems to afflict most of the media these days. Not sure there are any real journalists, who actually investigate stories anymore. They seem to cut and paste each others opinions.

[kirkster501]

42 minutes ago, Tomjo59 said:

I think it’s called ‘dumbing down’.

Seems to afflict most of the media these days. Not sure there are any real journalists, who actually investigate stories anymore. They seem to cut and paste each others opinions.

Yes, it's dumbing down alright.  But a lot of the population is much less well-read than you might think.  People interested in astronomy, on this forum, will by virtue of the topic's very nature be in the higher percentiles when it comes to intelligence and general knowledge.   I used to be incredulous at what by late wife, a theory of knowledge teacher at a local college, used to tell me about this.    She told me that many people think Paris is in Italy for instance.....  And what continent is Egypt located in?  Spain.... The President of the United States?  Ronald Thatcher.....  🙄🙈  There were papers on this she showed me, chuckling over them.

Back on topic.  Still, The Planets is a nice watch on Tuesday evenings.

[Star101]

On 15/06/2019 at 11:04, Tomjo59 said:

I’ve watched the latest program of Prof Cox’s ‘The Planets’ series, about Jupiter.

He states that computer models of the solar system’s formation  indicate that Jupiter migrated towards the inner solar system quite early in its history, explaining several ‘odd’ features, such as the small size of Mars, lack of ‘Super Earth’s’ etc. Jupiter then migrated outwards again, apparently.

However, it didn’t seem clear from his description exactly WHY Jupiter should have performed these migrations.

Did I miss something?

From what I recall, and I have slept since then, Saturn formed and help pull Jupiter back out. 

I think these type of things happen due to frequencies of orbit....Moons going around planets show similar things.

 

[Marvin Jenkins]

From some of the comments about this production I found myself humming My generation by The Who. 

Its just a whole new format for a whole new generation that may well go out and buy a scope and be the future of this website. Let’s hope, maybe ‘The Prof’ will be a catalyst not some guy looking into the distance working out what to spend his fee on.

Marvin!