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A Nine-Planet Solar System Once More? NASA Telescope May RevealNew Planet, Tyche
Dr J R Stockton wrote:
With an assumed mass of 4 Jupiters, such a planet would be very easy to detect given 19th century (or earlier) technology and sufficient patience. It will displace the barycentre of the solar system periodically by of the order of 250 AU, and Sun and Earth both orbit that barycentre. That will easily be detected by parallax measurements of many of the nearer stars, assumed to be on the average fixed. Unfortunately, the orbital period is of the order of 1.8 M years. Sam Wormley wrote: Jupiter at a distance of ~ 5AU has a much greater effect on the Sun than would a 4 Jupiter-mass planet beyond the Kuiper belt. I think you missed his point. He's not talking about somehow measuring the tidal effect or gravitational force of the planet (either Jupiter or the putative Tyche) on the Sun, which would indeed be much greater for Jupiter; he's talking about the gravitational wobble, which is basically proportional to mass times orbital distance. The wobble induced by Tyche would be vastly greater than Jupiter's, but it would have a correspondingly low frequency. So...easy, but tedious. -- Brian Tung The Astronomy Corner at http://www.astronomycorner.net/ Unofficial C5+ Page at http://www.astronomycorner.net/c5plus/ My PleiadAtlas Page at http://www.astronomycorner.net/pleiadatlas/ My Own Personal FAQ at http://www.astronomycorner.net/reference/faq.html |
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A Nine-Planet Solar System Once More? NASA Telescope May RevealNew Planet, Tyche
On Feb 21, 4:38*pm, (Brian Tung) wrote:
Dr J R Stockton wrote: With an assumed mass of 4 Jupiters, such a planet would be very easy to detect given 19th century (or earlier) technology and sufficient patience. *It will displace the barycentre of the solar system periodically by of the order of 250 AU, and Sun and Earth both orbit that barycentre. *That will easily be detected by parallax measurements of many of the nearer stars, assumed to be on the average fixed. Unfortunately, the orbital period is of the order of 1.8 M years. Sam Wormley wrote: * *Jupiter at a distance of ~ 5AU has a much greater effect on the Sun * *than would a 4 Jupiter-mass planet beyond the Kuiper belt. I think you missed his point. *He's not talking about somehow measuring the tidal effect or gravitational force of the planet (either Jupiter or the putative Tyche) on the Sun, which would indeed be much greater for Jupiter; he's talking about the gravitational wobble, which is basically proportional to mass times orbital distance. *The wobble induced by Tyche would be vastly greater than Jupiter's, but it would have a correspondingly low frequency. *So...easy, but tedious. -- Brian Tung The Astronomy Corner athttp://www.astronomycorner.net/ *Unofficial C5+ Page athttp://www.astronomycorner.net/c5plus/ *My PleiadAtlas Page athttp://www.astronomycorner.net/pleiadatlas/ *My Own Personal FAQ athttp://www.astronomycorner.net/reference/faq.html Yes, extremely slow wobble caused by Tyche. |
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A Nine-Planet Solar System Once More? NASA Telescope May Reveal New Planet, Tyche
In sci.astro.amateur message , Mon,
21 Feb 2011 16:38:38, Brian Tung posted: Dr J R Stockton wrote: With an assumed mass of 4 Jupiters, such a planet would be very easy to detect given 19th century (or earlier) technology and sufficient patience. It will displace the barycentre of the solar system periodically by of the order of 250 AU, and Sun and Earth both orbit that barycentre. That will easily be detected by parallax measurements of many of the nearer stars, assumed to be on the average fixed. Unfortunately, the orbital period is of the order of 1.8 M years. Sam Wormley wrote: Jupiter at a distance of ~ 5AU has a much greater effect on the Sun than would a 4 Jupiter-mass planet beyond the Kuiper belt. I think you missed his point. He's not talking about somehow measuring the tidal effect or gravitational force of the planet (either Jupiter or the putative Tyche) on the Sun, which would indeed be much greater for Jupiter; he's talking about the gravitational wobble, which is basically proportional to mass times orbital distance. The wobble induced by Tyche would be vastly greater than Jupiter's, but it would have a correspondingly low frequency. So...easy, but tedious. It appears that you both failed to notice my "and sufficient patience". Nor that although I referred to 19th century technology, I did not say that it could have been be done within the 19th century. IIRC, in c19 it was possible to measure the parallax of the nearer stars using a baseline of 2 AU. So the question is one of how long does it take for Tyche to displace Sol (corrected for other planets) by 2 AU from a straight path, given that in 1.8M years it can swing Sol around a circle of radius 60 AU (if that is the figure). That's clearly over a century. -- (c) John Stockton, nr London, UK. Turnpike v6.05 MIME. Web http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms and links; Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc. No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News. |
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A Nine-Planet Solar System Once More? NASA Telescope May RevealNew Planet, Tyche
Dr J R Stockton wrote:
It appears that you both failed to notice my "and sufficient patience". Nor that although I referred to 19th century technology, I did not say that it could have been be done within the 19th century. I didn't miss your "and sufficient patience"; I was agreeing with it with my "easy but tedious." -- Brian Tung (posting from Google Groups) The Astronomy Corner at http://www.astronomycorner.net/ Unofficial C5+ Page at http://www.astronomycorner.net/c5plus/ My PleiadAtlas Page at http://www.astronomycorner.net/pleiadatlas/ My Own Personal FAQ at http://www.astronomycorner.net/reference/faq.html |
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