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Brian Albin
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Reged: 08/22/06

Loc: Western Oregon
Is Bode’s Law Universal?
      #5596807 - 12/30/12 07:34 PM

The “Law” of Titius & Bode to describe the spacing of planets in our Solar system is:
Distance in AU = 0.4 + 2n x 0.075 where the exponent n is the ordinal number of the planet as Mercury 1, Venus 2, Earth 3; and AU is the distance of Earth to the Sun.

I have been wondering if this spacing exists in other planetary systems. Does someone here know if the telescope that is looking for exoplanets is able to measure their spacing from each other, or their distance from their sun?


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Rick Woods
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Reged: 01/27/05

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Re: Is Bode’s Law Universal? new [Re: Brian Albin]
      #5596824 - 12/30/12 07:45 PM

"Bode's Law" isn't even a law in our own Solar System. If it were, Neptune would be 9 AU farther out than it is.
I doubt that anyone is even thinking about it in relation to other systems.


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Brian Albin
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Reged: 08/22/06

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Re: Is Bode’s Law Universal? new [Re: Rick Woods]
      #5596841 - 12/30/12 07:55 PM

The Law may be accurate if it describes an original state, so that the deviations from it are seen to be adjustments which have occurred over time due an influencing force.

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GlennLeDrew
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Re: Is Bode’s Law Universal? new [Re: Brian Albin]
      #5596855 - 12/30/12 08:01 PM

Dynamicists propose that our solar system originally had the planets in a substantially different arrangement. The 'elegantly neat' "Bodean" spacing of today could be merely accidental. Exoplanetary systems, as so far found, seem to depart from this 'law' almost universally.

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InterStellarGuy
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Reged: 06/25/08

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Re: Is Bode’s Law Universal? new [Re: GlennLeDrew]
      #5597330 - 12/31/12 02:48 AM

So what you are all saying then is that it does not Bode well for the idea of using this to extrapolate data from exoplanetary systems?

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Mister T
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Reged: 02/01/08

Loc: Upstate NY
Re: Is Bode’s Law Universal? new [Re: InterStellarGuy]
      #5597560 - 12/31/12 09:10 AM

you don't understand the gravity of the situation.

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Ravenous
sage


Reged: 11/14/09

Loc: UK
Re: Is Bode’s Law Universal? new [Re: Mister T]
      #5597697 - 12/31/12 10:34 AM

I'm sure everything will fall into place eventually

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FeynmanFan
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Re: Is Bode’s Law Universal? new [Re: Ravenous]
      #5598018 - 12/31/12 01:49 PM

This thread is getting spaced out.

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Rick Woods
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Re: Is Bode’s Law Universal? new [Re: FeynmanFan]
      #5598102 - 12/31/12 02:39 PM

But the original theory was Bodeacious.

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Dave Mitsky
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Re: Is Bode’s Law Universal? new [Re: Rick Woods]
      #5598144 - 12/31/12 03:06 PM

If the puns get any worse in this thread, somebody will have to lay down the (Bode's) law.

Dave Mitsky


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Charlie B
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Reged: 03/22/08

Loc: Sterling, Virginia
Re: Is Bode’s Law Universal? new [Re: Dave Mitsky]
      #5598183 - 12/31/12 03:23 PM

They just hit bottom.

Charlie B


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scopethis
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Re: Is Bode’s Law Universal? new [Re: Charlie B]
      #5598282 - 12/31/12 04:10 PM

Bode's Law only applies to women and gravity....

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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Is Bode’s Law Universal? new [Re: scopethis]
      #5598288 - 12/31/12 04:16 PM

There's a certain resonance about this discussion.

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Rick Woods
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Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5598320 - 12/31/12 04:35 PM

Dave,

Quote:

Science is a bazaar, not a cathedral




As in "Winchester Cathedral (Bode-oh-de-oh-doh)"?


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llanitedave
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Is Bode’s Law Universal? new [Re: Rick Woods]
      #5598706 - 12/31/12 08:27 PM

You're bringin' me down!

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llanitedave
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Reged: 09/26/05

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Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5598716 - 12/31/12 08:37 PM

Just to momentarily distract from the world-class humor appearing in this thread, a thought did occur to me about planetary spacings. Unfortunately, I haven't followed up this thought with any research, so if someone wants to knock me down with contrary facts, so be it.

Bode's law seems to operate as a result of resonances derived from the masses and orbital relationships of Jupiter and Saturn. It's thought that, early in the Solar System's history, Jupiter and Saturn migrated from their zones of origin, setting up new gravitational resonances and disrupting the orbits of Uranus and Neptune, in the process also causing the Late Heavy Bombardment.

Had Jupiter formed with a different mass and/or at a different distance from the Sun, these resonance patterns would be very different, and I'm thinking that the modern spacing of orbits in the inner Solar system would also be different.

Is it possible that the migration of Jupiter and Saturn, and the different resonance patterns that might have created, could also have led to a migration of Earth, Mars, and Venus from an initial distance from the Sun to their current positions? I don't know of any evidence that the original length of the Earth's year was any different than today's, but then, I wouldn't expect such evidence to be preserved after 3.9 billion years.

MAYBE, though, relevant evidence could be preserved on Mars?


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Rick Woods
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Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5598847 - 12/31/12 10:29 PM

Nahhhh!

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Jarad
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Re: Is Bode’s Law Universal? new [Re: Rick Woods]
      #5599199 - 01/01/13 08:38 AM

I think that Dave is right about resonances. The planets follow ~2-fold increases in period because those are stable. There are exceptions when masses are low or the planets are far apart (in either case, the result is that the influence of gravity on each other is small enough to ignore).

So, we should expect to see in general that nearby planets tend to follow stable resonance patterns around the most massive one(s). Those arrangements are stable, so once a system hits them, they will tend to stay that way. Other arrangements are possible, but will be unstable and keep shifting until either a planet gets ejected or they fall into a stable configuration.

Jarad


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Ravenous
sage


Reged: 11/14/09

Loc: UK
Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5600765 - 01/02/13 06:49 AM

Quote:

I don't know of any evidence that the original length of the Earth's year was any different than today's, but then, I wouldn't expect such evidence to be preserved after 3.9 billion years.




Fossil record evidence (stromatolites etc.) indicates shorter day in the past, and that tidal influence has lengthened it. But that only goes back less than a billion years I think. (Strictly speaking I think it measured only the number of days per year, too.)

So the evidence we really want (year length, not merely days per year) isn't there.

However, as we can now measure orbital periods in other systems, a nice long term project would be to look for variations in known protoplanetary systems. If there are any such systems identified yet.

Unfortunately current postgrads working in this field might be leaving it to their grandchildren to actually publish the results...


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llanitedave
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Reged: 09/26/05

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Re: Is Bode’s Law Universal? new [Re: Ravenous]
      #5601362 - 01/02/13 02:36 PM

I think these types of migrations operate over millions of years, so it would be tough to find with real-time observations.

One reason I speculated that Mars might retain the evidence is because it has no large moon to cause tidal slowing of its rotation. If the number of days in its year were to change, it would almost certainly mean a change in actual orbital time, rather than simply a rotational slowing.


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BillFerris
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Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5601592 - 01/02/13 05:04 PM

If Earth has migrated from a different orbit to its current distance from the Sun, then the Moon tagged along for the ride. One could approach the question from a standpoint of what one would expect to find at or near the lunar surface. For example, should older lunar impact craters exhibit certain characteristics if they were made by asteroids typically orbiting at different distances from the Sun?

Another approach could be to compare a model of Earth's structure--especially the core--with models of the solar nebula and the distribution of heavy elements during the time of planetary formation. If Earth had formed elsewhere, should its iron core be smaller or larger? Differently composed?

Finally, If the Earth were in a different orbit 1 to 2 billion years ago, shouldn't the geological record retain some evidence of climatic evolution tied to a move from the former to the current location? There are places on Earth where one can gain relatively easy access to rock layers that were formed 1 to 2 billion years ago. Let's have a look.

As to the question of whether or not Earth migrated to its current orbit from another, I look at the two options--formed here and survived because it's a stable orbit versus formed in an unstable orbit and was lucky enough to move to a stable orbit--and I lean in favor of the former. In the absence of persuasive evidence to the contrary, it seems more likely that a planet will remain in the stable orbit in which it formed versus moving from an unstable to a stable location.

Bill in Flag


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Rick Woods
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Re: Is Bode’s Law Universal? new [Re: BillFerris]
      #5601634 - 01/02/13 05:30 PM

Tsk! Hasn't anyone read Velikovsky?

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llanitedave
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Re: Is Bode’s Law Universal? new [Re: Rick Woods]
      #5602102 - 01/02/13 10:52 PM

In all fairness to Velikovsky, it was he who first got me interested in science.

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llanitedave
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Re: Is Bode’s Law Universal? new [Re: BillFerris]
      #5602125 - 01/02/13 11:06 PM

Quote:

If Earth has migrated from a different orbit to its current distance from the Sun, then the Moon tagged along for the ride. One could approach the question from a standpoint of what one would expect to find at or near the lunar surface. For example, should older lunar impact craters exhibit certain characteristics if they were made by asteroids typically orbiting at different distances from the Sun?

Another approach could be to compare a model of Earth's structure--especially the core--with models of the solar nebula and the distribution of heavy elements during the time of planetary formation. If Earth had formed elsewhere, should its iron core be smaller or larger? Differently composed?

Finally, If the Earth were in a different orbit 1 to 2 billion years ago, shouldn't the geological record retain some evidence of climatic evolution tied to a move from the former to the current location? There are places on Earth where one can gain relatively easy access to rock layers that were formed 1 to 2 billion years ago. Let's have a look.

As to the question of whether or not Earth migrated to its current orbit from another, I look at the two options--formed here and survived because it's a stable orbit versus formed in an unstable orbit and was lucky enough to move to a stable orbit--and I lean in favor of the former. In the absence of persuasive evidence to the contrary, it seems more likely that a planet will remain in the stable orbit in which it formed versus moving from an unstable to a stable location.

Bill in Flag




We're looking back way further than 1-2 billion years. We're looking for things happening associated with the Late Heavy Bombardment some 3.9 billion years ago, in response to the hypothesized dynamic migration of the orbits of the outer planets. Climatic evolution would be obscured by a combination of the evolution of life and photosynthesis, the steady increase in the solar output, the bombardment itself, and the changing nature of the crust and the oceans as plate tectonics developed.

We have a very dynamic history to deal with, and much of its effects are un-postdictable.

As for the stability of past orbits, that again is hard to establish -- in fact, it's even hard to agree on what we mean by "stable". It's obvious that the original orbits of Jupiter and Saturn were unstable, as they influenced each other and were influenced in turn by the billions of bodies sharing their zones. If the Earth's original orbit was stable, the question is whether it would have become unstable due to the increasing perturbations of Jupiter's influence as the latter migrated ever closer to the Sun. That's my real question. And if the Earth's orbit was influenced, that of Mars would have been affected even more.

Since the formation of the Solar System was such a chaotic process, I hesitate to claim that any planetary orbit was stable until all the debris was cleared out and the different resonances settled down.


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Rick Woods
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Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5602251 - 01/03/13 12:59 AM

Quote:

We have a very dynamic history to deal with, and much of its effects are un-postdictable.





Un-postdictable! Ooo, I like that!


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Brian Albin
Seeker


Reged: 08/22/06

Loc: Western Oregon
Re: Is Bode’s Law Universal? new [Re: Rick Woods]
      #5602302 - 01/03/13 02:18 AM

I don’t want to interrupt this flow of ideas (at least not now that those damned puns have stopped), But I wanted to say hello and let everyone know I have read what has been posted and thank you for it. It is good to have a place to share an idea and get it thought over by those who know more about it than I.

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Dave Mitsky
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Re: Is Bode’s Law Universal? new [Re: Brian Albin]
      #5603003 - 01/03/13 01:27 PM

There's an article on a new model of Jupiter's rolling-stone past at http://www.nasa.gov/topics/solarsystem/features/young-jupiter.html

Dave Mitsky


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