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IWETHEY Home / IWETHEY Board / Science Forum / Am I in the Dark Ages or something?
Post #209,363
by warmachine
6/1/05 12:07:05 PM
Reply
New Am I in the Dark Ages or something?
I thought Copernicus threw out this idea by using a solar system, which explained why the planets appeared to loop in their orbits and didn't require bizarrely elliptical orbits. Isn't the idea that the Sun orbits the Earth one of the defining accusations thrown at the Dark Ages? I doubt the Greeks believed in this, just like they didn't believe in a flat Earth. Like flat Earthers, aren't advocates of Geocentrism beyond contempt and into the realm of pity?
Matthew Greet


But we must kill them. We must incinerate them. Pig after pig, cow after cow, village after village, army after army. And they call me an assassin. What do you call it when the assassins accuse the assassin? They lie. They lie and we must be merciful to those who lie.
- Colonol Kurtz, Apocalypse Now.
Post #209,390
by ben_tilly
6/1/05 2:48:36 PM
Reply
New You've jumbled the story
The Ptolemaic system used epicycles to make the orbits all come out to what they should around the Earth.

Coopernicus used only circles, but made the Earth go around the Sun, and then all of the planets go around the Sun as well. His system was more complex than the Ptolemaic. (And his justifications were extremely mystical points about what he thought was natural.)

The idea that orbits were elliptical is due to Kepler (who supported the Coopernican system). Kepler's 3 laws say:

  1. Planets move in orbits that are ellipses.
  2. The planets move such that the line between the Sun and the Planet sweeps out the same area in the same area in the same time no matter where in the orbit.
  3. The square of the period of the orbit of a planet is proportional to the mean distance from the Sun cubed.

(Note, you thought that the "weird elliptical orbits" were Ptolemaic. They were not.)

These laws were found to be very close, but not quite perfect. However Isaac Newton demonstrated that the second law implies that all forces on the planets are directed towards the Sun. The third law implies that the forces in question vary as distance squared. He verified that these two facts explain why the orbits are elliptical (actually they are conic sections). He found that if the force pulling us to the Earth also varies as distance squared, he could explain the Moon's orbit. He then showed that if he assumed that all pairs of masses attracted each other in this matter he could not only explain the above orbital facts, but he could explain a plethora of other phenomena, including tides, the precession of the Earth and the orbits of moons around other planets.

Cheers,
Ben
I have come to believe that idealism without discipline is a quick road to disaster, while discipline without idealism is pointless. -- Aaron Ward (my brother)
     Geocentrism - (bluke) - (41) - June 1, 2005, 10:29:52 AM EDT
         other than moving to the religious forum sure - (boxley) - (1) - June 1, 2005, 10:46:26 AM EDT
             I wasn't actually referring to that - (bluke) - June 1, 2005, 10:50:21 AM EDT
         It's a bogus argument. - (Another Scott) - June 1, 2005, 10:50:37 AM EDT
         Here is one of his responses ... - (bluke) - (28) - June 1, 2005, 11:21:07 AM EDT
             You're arguing with an idiot. - (pwhysall) - (2) - June 1, 2005, 11:24:10 AM EDT
                 I would but ... - (bluke) - (1) - June 1, 2005, 11:27:44 AM EDT
                     You can't control what other people do. - (Another Scott) - June 1, 2005, 11:56:00 AM EDT
             my answer to this specific - (boxley) - (22) - June 1, 2005, 11:36:12 AM EDT
                 also why do toilets/huricanes/typhoons rotate in different - (boxley) - (21) - June 1, 2005, 11:46:13 AM EDT
                     Toilets don't depend on hemisphere - (ben_tilly) - (20) - June 1, 2005, 05:40:37 PM EDT
                         eh, flush your can, static flush your can - (boxley) - (19) - June 1, 2005, 07:22:21 PM EDT
                             Google for proof if you want - (ben_tilly) - (18) - June 1, 2005, 08:17:20 PM EDT
                                 I just remember when I became a frog - (boxley) - (17) - June 1, 2005, 08:40:32 PM EDT
                                     Somebody was playing games on you - (ben_tilly) - (16) - June 1, 2005, 09:04:52 PM EDT
                                         having dug in the bowels of many a toilet - (boxley) - (15) - June 1, 2005, 09:50:37 PM EDT
                                             It probably has more to do with the toilet design. - (Another Scott) - (14) - June 1, 2005, 09:58:41 PM EDT
                                                 again let static and meerkat pull the top off their tank - (boxley) - (13) - June 1, 2005, 10:17:16 PM EDT
                                                     Sure. But ye canna change the laws of physics! - (Another Scott) - June 1, 2005, 10:25:30 PM EDT
                                                     Perhaps it isn't obvious to you... - (ben_tilly) - (10) - June 1, 2005, 11:36:50 PM EDT
                                                         You actually spent time researching this? - (bionerd) - (3) - June 2, 2005, 09:29:55 AM EDT
                                                             It's not just a toilet, it's a belief system. - (admin) - (2) - June 2, 2005, 11:01:17 AM EDT
                                                                 ICLRPD (new thread) - (Steve Lowe) - June 2, 2005, 11:33:33 AM EDT
                                                                 ICLRPD (new thread) - (static) - June 2, 2005, 08:26:43 PM EDT
                                                         okay, we have 10 toilets in this building I will flush them - (boxley) - (5) - June 2, 2005, 09:55:10 AM EDT
                                                             ICLRPD (new thread) - (drewk) - June 2, 2005, 10:31:49 AM EDT
                                                             Invalid - (Andrew Grygus) - (1) - June 2, 2005, 11:40:54 AM EDT
                                                                 Also invalid because ... - (drewk) - June 2, 2005, 11:43:43 AM EDT
                                                             We have a counter-clockwise one here. - (admin) - (1) - June 2, 2005, 02:47:59 PM EDT
                                                                 good enough I retract my statement about earth rotation - (boxley) - June 2, 2005, 03:00:49 PM EDT
                                                     Actually, we can't perform that experiment. - (static) - June 2, 2005, 12:37:47 AM EDT
             He falls apart at the third line - (JayMehaffey) - June 1, 2005, 12:46:02 PM EDT
             He's an idiot - (ben_tilly) - June 1, 2005, 05:37:02 PM EDT
         Am I in the Dark Ages or something? - (warmachine) - (1) - June 1, 2005, 12:07:05 PM EDT
             You've jumbled the story - (ben_tilly) - June 1, 2005, 02:48:36 PM EDT
         Yeah, here in California we have the Flat Earth Society**. - (Andrew Grygus) - (6) - June 1, 2005, 12:58:07 PM EDT
             part I dont understand is if at sealevel the horizon - (boxley) - (5) - June 1, 2005, 01:17:17 PM EDT
                 He believes in a geocentric universe, not a flat Earth -NT - (ben_tilly) - (3) - June 1, 2005, 02:36:31 PM EDT
                     was responding to Andrews flat earth stuff -NT - (boxley) - (2) - June 1, 2005, 03:00:52 PM EDT
                         Yeah, it's called 'topic drift' . . . - (Andrew Grygus) - June 1, 2005, 03:08:32 PM EDT
                         Oops. - (ben_tilly) - June 1, 2005, 05:42:38 PM EDT
                 Hey, ask them, not me . . . - (Andrew Grygus) - June 1, 2005, 02:50:38 PM EDT

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