Wednesday, August 6, 2014

Thermal Gravity And Lost Innocence

From the web,  The surface temperature of planet as a function of   \(x\)  distance from the Sun is given by,

\(T(x) = \cfrac{A}{\sqrt{x}}=A(x)^{-\cfrac{1}{2}}\)

\(A\)  is a constant of proportionality.  Differentiating with respect to  \(x\),

\({ T }^{ ' }(x)\quad =-\cfrac { A }{ 2 } { (x) }^{ -\cfrac { 3 }{ 2 }  }\)

\( { T }^{ '' }(x)\quad =\cfrac { 3A }{ 4 } { (x) }^{ -\cfrac { 5 }{ 2 }  }\)

and from the post "What Thermal Gravity?  Too Hot To Handle..."

\( g_{ T } =v^2\cfrac{x}{T(x)}\cfrac { d^{ 2 }T(x) }{ d x^{ 2 } } \)

\( g_{ T } =v^2\cfrac{x(x)^\cfrac{1}{2}}{A}\cfrac { 3A }{ 4 } { (x) }^{ -\cfrac { 5 }{ 2 }  } \)

\(g_{ T }=\cfrac { 3 }{ 4x } v^{ 2 }=\cfrac{a}{x}=S_TT^2\)

where \(v\) is the speed of \(T\) as it travels across the temperature profile,  \(a\)  a constant,  and  \(S_T\)  a constant of proportionality with the unit ms-2J-2.  The last equation relates  \(g_T\) directly to  \(T\)  this will bring us to a relationship for space density and temperature in another post.

Unfortunately,  a plot of a family of curves of \(\cfrac{a}{x}\)  together with  \(\cfrac{1}{x^2}\),


shows that   \(g_T={a}/{x}\)  does not intersect  \(g={1}/{x^2}\)  again after its goes above \({1}/{x^2}\)   ie after \(g_T>g\)  along  \(x\).  \(g_T\)  has to be greater than  \(g\)  at the start  \(x=x_o\)  for  \(T\)  to flow.  This is the case for nebula where the boundary,  \(g_T-g=0\)  does not exist, but not a general case of planetary spheres and rings where  \(g_T>g\)  for  \(T\) to flow outwards and then  \(g_T-g=0\) at some distance \(x_{ring}\) beyond which  \(g_T\)  oscillate up and down  \(g\).  It is not appropriate to repesent gravity of the hot spot here using  \(1/x^2\).

However, if instead we use \(e^{-x}\) to represent gravity,


Both Nebula and planetary spheres and rings scenarios are encountered as \({1}/{x}\) is scaled appropriately.   The curve marked as  \({a}/{x}\) is higher than the gravity curve  \(g\)  and does not intersect  \(g\).  This is the Nebula scenario where  \(T\) spreads over vast distances.

All other curves below  \({a}/{x}\) cross  \(g\) twice.  The second intersection further out along  \(x\) marks a gap where the net gravity due to  \(g\)  and  \(g_T\)  points away from it, before and after that point.

It should be noted that, beyond the first intersection,  \(T\)  redistributes and  \(g_T\)  is no longer of the form  \({a}/{x}\)  but is expected to have a sinusoidal component and intersect  \(g\)  again multiple times.

Below is a plot of (1/x)*cos(2*x)^2/(cos(2)^2) to show how  \(g_T\)  might look like,


If  \(T(x)\)  can be determined from observations,  then logically  \(g_T\)  should come after  \(T(x)\)  has been formulated.  We shall do that in the next post.

\(g_T\) was derived from an expression for  \(T\)  temperature, based on an moving mass analogy for \(T\), together with the assumption that  \(T\)  propagates as a wave, at a constant velocity  \(v\).  If  \(T(x)\)  can be obtained empirically,  then  \(g_T\)  can be derived directly with just one assumption of how  \(T\)  affects  \(g_T\)  through  interacting with space.