Bartosz Milewski
Apr7-04, 08:42 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resize=yes,status=no,wi dth=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>\n"Peter Tobias" <tobiasep@comcast.net> wrote in message\nnews:ItOdnY3zWL9RQPHdRVn-gg@comcast.com...\n> I remember something of a 1/r^6 decay over distance r, weaker over long\n> distances than 1/r^2 forces, of course, but not as weak as exponentially\n> decaying forces.\n\nYou\'re right, my mistake. It\'s the Yukawa force (nuclear force) that fades\nexponentially.\n\n> > Stable systems kept together by gravity\n> > have to be at least the size of comets or planetoids.\n>\n> Do you want to express that comets or planetoids are hold together by\n> gravity? I think they rely on ionic, covalent or metallic bonding.\n> Also dipole forces can hold matter together like a water sphere in zero\n> gravity (with some vapor pressure outside). All these examples,\n> however, contain atomic matter.\n\nWhat you\'re saying is definitely true about meteors, but as you go towards\nlarger bodies--comets and planetoids--gravity plays bigger and bigger role.\nThese object have a solid core but they also have some loose material\n(gravel, dust, etc.). It\'s hard to pinpoint exactly at what size gravity\nbecomes the leading force.\n\n\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>"Peter Tobias" <tobiasep@comcast.net> wrote in message
news:ItOdnY3zWL9RQPHdRVn-gg@comcast.com...
> I remember something of a 1/r^6 decay over distance r, weaker over long
> distances than 1/r^2 forces, of course, but not as weak as exponentially
> decaying forces.
You're right, my mistake. It's the Yukawa force (nuclear force) that fades
exponentially.
> > Stable systems kept together by gravity
> > have to be at least the size of comets or planetoids.
>
> Do you want to express that comets or planetoids are hold together by
> gravity? I think they rely on ionic, covalent or metallic bonding.
> Also dipole forces can hold matter together like a water sphere in zero
> gravity (with some vapor pressure outside). All these examples,
> however, contain atomic matter.
What you're saying is definitely true about meteors, but as you go towards
larger bodies--comets and planetoids--gravity plays bigger and bigger role.
These object have a solid core but they also have some loose material
(gravel, dust, etc.). It's hard to pinpoint exactly at what size gravity
becomes the leading force.
news:ItOdnY3zWL9RQPHdRVn-gg@comcast.com...
> I remember something of a 1/r^6 decay over distance r, weaker over long
> distances than 1/r^2 forces, of course, but not as weak as exponentially
> decaying forces.
You're right, my mistake. It's the Yukawa force (nuclear force) that fades
exponentially.
> > Stable systems kept together by gravity
> > have to be at least the size of comets or planetoids.
>
> Do you want to express that comets or planetoids are hold together by
> gravity? I think they rely on ionic, covalent or metallic bonding.
> Also dipole forces can hold matter together like a water sphere in zero
> gravity (with some vapor pressure outside). All these examples,
> however, contain atomic matter.
What you're saying is definitely true about meteors, but as you go towards
larger bodies--comets and planetoids--gravity plays bigger and bigger role.
These object have a solid core but they also have some loose material
(gravel, dust, etc.). It's hard to pinpoint exactly at what size gravity
becomes the leading force.