shape of the solar system [Archive]

Ralph E. Frost

Apr24-04, 11:18 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>While the traditional picture of the solar system show it as a flat disc, is\nits (exaggerated, dynamic) shape more like a ice cream cone, with the sun in\nthe leading apex position, roaring along the path of action followed by the\nspiralling trail of planets and dust clouds?\n\nAnd, while our line of sight measures indicate a flat disc with purely\nellipital orbits, if all rays of light follow a strongly, naturally curved\npath, can we actually tell how flat the disc is?\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>While the traditional picture of the solar system show it as a flat disc, is
its (exaggerated, dynamic) shape more like a ice cream cone, with the sun in
the leading apex position, roaring along the path of action followed by the
spiralling trail of planets and dust clouds?

And, while our line of sight measures indicate a flat disc with purely
ellipital orbits, if all rays of light follow a strongly, naturally curved
path, can we actually tell how flat the disc is?

Arnie King

Apr27-04, 02:03 PM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>The plane defined by the positions of a planet\'s center of mass at\nthree times,\nin the limit that these times approach some time t, is called the\nosculating plane at time t. This plane contains the center of mass of\nthe sun, so the cone shape you suggested does not occur.\n\nThe osculating plane is constant in the case of a two-body system with\nthe sun and the planet both having radially symmetric mass\ndistributions. However, the orbital planes of the real planets slowly\nchange because of the forces between the planets, and perhaps the\noblateness of the sun. (I expect this effect is quite small.) This\nmeans that an orbit is really a space curve that does not define a\nplane.\n\nBy the way, each planet has its own plane. Pluto\'s plane is rather\nstrongly inclined to all the others, which do lie pretty close\ntogether.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>The plane defined by the positions of a planet's center of mass at
three times,
in the limit that these times approach some time t, is called the
osculating plane at time t. This plane contains the center of mass of
the sun, so the cone shape you suggested does not occur.

The osculating plane is constant in the case of a two-body system with
the sun and the planet both having radially symmetric mass
distributions. However, the orbital planes of the real planets slowly
change because of the forces between the planets, and perhaps the
oblateness of the sun. (I expect this effect is quite small.) This
means that an orbit is really a space curve that does not define a
plane.

By the way, each planet has its own plane. Pluto's plane is rather
strongly inclined to all the others, which do lie pretty close
together.