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Brian Albin
Seeker


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
Postmaster
*****

Reged: 01/27/05

Loc: Inner Solar System
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
Seeker


Reged: 08/22/06

Loc: Western Oregon
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
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
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
professor emeritus
*****

Reged: 06/25/08

Loc: Overland Park, KS
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
Pooh-Bah


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
professor emeritus
*****

Reged: 02/18/11

Loc: N Colo front range
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
Postmaster
*****

Reged: 01/27/05

Loc: Inner Solar System
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
Postmaster
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Reged: 04/08/02

Loc: PA, USA, Planet Earth
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
scholastic sledgehammer


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
Postmaster
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Reged: 05/30/08

Loc: Kingman, Ks
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
Humble Megalomaniac
*****

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
Postmaster
*****

Reged: 01/27/05

Loc: Inner Solar System
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
Humble Megalomaniac
*****

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
Humble Megalomaniac
*****

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
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
Postmaster
*****

Reged: 01/27/05

Loc: Inner Solar System
Re: Is Bode’s Law Universal? new [Re: llanitedave]
      #5598847 - 12/31/12 10:29 PM

Nahhhh!

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Jarad
Postmaster
*****

Reged: 04/28/03

Loc: Atlanta, GA
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
Humble Megalomaniac
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Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
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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