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Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it?

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On 8/1/15 7:08 PM, Double-A wrote:
> On Saturday, August 1, 2015 at 3:11:12 PM UTC-7, Sam Wormley wrote:
>> On 8/1/15 5:07 PM, reber g=emc^2 wrote:
>>> On Friday, July 31, 2015 at 6:49:43 PM UTC-7, Sam Wormley wrote:
>>>> If the Sun [or a Black Hole] pulls things directly toward it, then why
>>>> does everything move in circles around it?
>>>>> http://www.askamathematician.com/2014/10/q-if-the-sun-pulls-things-directly-toward-it-then-why-does-everything-move-in-circles-around-it/
>>>>
>>>>> So that's how a planet can accelerate toward the Sun forever without
>>>>> getting any closer.  The sideways motion of planets is due to the
>>>>> fact that if a planet were not moving sideways, it would find itself
>>>>> in the Sun in short order.  In fact, the Sun is nothing more than a
>>>>> massive collection of all the matter from the formation of the solar
>>>>> system that wasn't moving sideways fast enough (which is nearly all
>>>>> of it).
>>>>>
>>>>> Why things end up in circular orbits is a more subtle question.  The
>>>>> quickest explanation is that things in not-circular orbits run into
>>>>> trouble until either their orbit is sufficiently round or they're
>>>>> destroyed.  It's not that circular orbits are somehow better, it's
>>>>> just that other orbits carry more risk of serious impacts or
>>>>> gravitational interactions (e.g., with Jupiter) that may lead to
>>>>> short, unfortunate orbits.
>>>>>
>>>>> Assuming that an orbit is stable, then it will be an ellipse (there's
>>>>> a post here on exactly why, but it's a whole thing.).  A circle is
>>>>> the simplest kind of ellipse, but ellipses can be extremely stretched
>>>>> out.  For example, comets have very elliptical orbits (like Sedna in
>>>>> the picture below).  In these orbits the comet is mostly moving
>>>>> toward and away from the Sun, so for them the Sun's pull mostly
>>>>> changes their speed and changes their direction less.
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> sci.physics is an unmoderated newsgroup dedicated
>>>> to the discussion of physics, news from the physics
>>>> community, and physics-related social issues.
>>>
>>> When as a kid I use to think of falling but side stepping and missing the sun. It works. Its easy to picture.It should be taught as a way of orbiting.TreBert
>>>
>>
>>     It was taught by Johannes Kepler about 400 years ago. It is known
>>     as Kepler's 1st Law. Planets are forever falling around the Sun in
>>     elliptical orbits.
>
>
> So, maybe Bert as a kid was reading Kepler.
>
> Double-A
>


   That... would be nice, indeed!


-- 

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If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Sam Wormley <swormley1@gmail.com> - 2015-07-31 20:49 -0500
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Fabian Russell <root@localhost.localdomain> - 2015-08-01 03:22 +0000
    Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? john <johnsefton288@gmail.com> - 2015-07-31 20:56 -0700
      Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? HVAC <Mr.HVAC@gmail.com> - 2015-08-02 06:11 -0400
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-01 15:07 -0700
    Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Sam Wormley <swormley1@gmail.com> - 2015-08-01 17:11 -0500
      Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Sam Wormley <swormley1@gmail.com> - 2015-08-01 20:56 -0500
      Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Double-A <double-a3@hush.com> - 2015-08-01 17:08 -0700
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-03 11:49 -0700
    Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Double-A <double-a3@hush.com> - 2015-08-03 12:00 -0700
      Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-03 12:08 -0700
        Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? HVAC <Mr.HVAC@gmail.com> - 2015-08-04 06:20 -0400
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "Y.Porat" <y.y.porat@gmail.com> - 2015-08-03 20:18 -0700
    Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "Buck Futter" <invalid@example.com> - 2015-08-05 22:32 -0700
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Nicolaas Vroom <nicolaas.vroom@pandora.be> - 2015-08-04 05:42 -0700
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-04 12:48 -0700
    Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Double-A <double-a3@hush.com> - 2015-08-04 13:45 -0700
  Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-08-04 13:05 -0700
    Re: If the Sun [or a Black Hole] pulls things directly toward it, then why does everything move in circles around it? Sam Wormley <swormley1@gmail.com> - 2015-08-04 16:13 -0500

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