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Did Venus Have A Moon?
nprev
post Oct 11 2006, 07:06 PM
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...or two?

http://skytonight.com/news/home/4353026.html


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Rob Pinnegar
post Oct 11 2006, 08:09 PM
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Cute, but it's just speculation. Nobody can prove or disprove that any such moons ever existed.

The presenter is listed as being an undergraduate... I'm guessing this is his fourth year thesis. Presumably it's being reported in the news because it "sounds exciting".

As far as the model's concerned, I'd been under the impression that Venus' slow rotation rate can be explained away by despinning due to solar tides acting on its atmosphere, because the atmosphere is so massive. (This is a dim recollection from years ago -- correct me if my memory is inaccurate here.) If that's correct, it's an important point, because it would make a second impact unnecessary, which would really simplify the model. *Any* moon, whether primordial, captured, or giant-impact-derived, would have spiralled into Venus after the planet's rotation was tidally slowed.

Guess the same goes for Mercury.
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JRehling
post Oct 11 2006, 09:07 PM
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Keep in mind that the rate of Venus's rotation, at its equator, is just a fast walk by a person. It is incredibly close to zero -- though not quite there. It's more likely to signify an attractor AT zero (eg, solar tides) than cosmic billiards which would have no such attractor.
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Posts in this topic
- nprev   Did Venus Have A Moon?   Oct 11 2006, 07:06 PM
- - Myran   I read it and agree that slow rotation of Venus ar...   Oct 11 2006, 08:01 PM
- - Jyril   I agree, the theory sounds a bit too complicated a...   Oct 11 2006, 08:08 PM
- - Rob Pinnegar   Cute, but it's just speculation. Nobody can pr...   Oct 11 2006, 08:09 PM
|- - JRehling   Keep in mind that the rate of Venus's rotation...   Oct 11 2006, 09:07 PM
|- - AndyG   QUOTE (Rob Pinnegar @ Oct 11 2006, 09:09 ...   Oct 12 2006, 08:41 AM
- - tasp   Whew, heady stuff. I think the odds for the Satur...   Oct 12 2006, 03:20 AM
- - nprev   I gotta agree with the majority opinion so far; th...   Oct 12 2006, 03:53 AM
- - edstrick   Venus's solar tidal drag on the solid body is ...   Oct 12 2006, 10:18 AM
|- - Rob Pinnegar   QUOTE (edstrick @ Oct 12 2006, 04:18 AM) ...   Oct 12 2006, 02:20 PM
- - RNeuhaus   QUOTE (nprev @ Oct 11 2006, 02:06 PM) ......   Oct 12 2006, 02:49 PM
|- - JRehling   QUOTE (RNeuhaus @ Oct 12 2006, 07:49 AM) ...   Oct 12 2006, 04:08 PM
|- - Rob Pinnegar   Hmmm. Would a satellite small enough to avoid disi...   Oct 12 2006, 04:58 PM
|- - RNeuhaus   QUOTE (JRehling @ Oct 12 2006, 11:08 AM) ...   Oct 12 2006, 06:53 PM
|- - JRehling   QUOTE (RNeuhaus @ Oct 12 2006, 11:53 AM) ...   Oct 12 2006, 08:25 PM
- - Bill Harris   QUOTE My initial thought was "but that requir...   Oct 12 2006, 03:42 PM
- - DonPMitchell   According to dynamics calculations by Alexandre Co...   Oct 12 2006, 07:36 PM
- - nprev   Interesting...but how about Mars' relatively r...   Oct 13 2006, 04:55 AM
|- - RNeuhaus   QUOTE (nprev @ Oct 12 2006, 11:55 PM) Int...   Oct 13 2006, 06:59 PM
- - nprev   Well, I'll be...I actually didn't know tha...   Oct 14 2006, 12:14 AM
|- - JRehling   QUOTE (nprev @ Oct 13 2006, 05:14 PM) Wel...   Oct 14 2006, 02:24 AM
- - nprev   Argh...my apologies for misunderstanding you, RN. ...   Oct 14 2006, 03:45 AM
|- - JRehling   QUOTE (nprev @ Oct 13 2006, 08:45 PM) wha...   Oct 14 2006, 04:59 AM
||- - ugordan   QUOTE (JRehling @ Oct 14 2006, 05:59 AM) ...   Oct 14 2006, 09:21 AM
||- - helvick   That was my thinking too. To nudge this slightly ...   Oct 14 2006, 11:17 AM
||- - JRehling   QUOTE (helvick @ Oct 14 2006, 04:17 AM) T...   Oct 15 2006, 04:59 AM
||- - helvick   QUOTE (JRehling @ Oct 15 2006, 05:59 AM) ...   Oct 15 2006, 06:07 AM
||- - JRehling   QUOTE (helvick @ Oct 14 2006, 11:07 PM) A...   Oct 15 2006, 03:32 PM
|- - RNeuhaus   QUOTE (nprev @ Oct 13 2006, 10:45 PM) Arg...   Oct 15 2006, 12:00 AM
|- - nprev   Delinquent thanks for the great "pocket...   Oct 19 2006, 09:27 AM
|- - diane   QUOTE (nprev @ Oct 19 2006, 05:27 AM) Del...   Oct 20 2006, 10:42 PM
- - Myran   QUOTE JRehling wrote: ...would we be here as an ad...   Oct 16 2006, 11:48 AM
|- - tty   QUOTE (Myran @ Oct 16 2006, 01:48 PM) Hal...   Oct 16 2006, 06:19 PM
|- - JRehling   QUOTE (tty @ Oct 16 2006, 11:19 AM) In ea...   Oct 16 2006, 06:35 PM
- - dvandorn   Here's a question: If this model is correct a...   Oct 21 2006, 02:11 AM
- - tasp   QUOTE (dvandorn @ Oct 20 2006, 09:11 PM) ...   Oct 21 2006, 02:24 AM
- - Rob Pinnegar   QUOTE (dvandorn @ Oct 20 2006, 08:11 PM) ...   Oct 24 2006, 08:57 PM


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