Friday, August 8, 2014

Gravity Exponential Form Again

Consider s space density function of the form,

\({ d }_{ s }(x)=A{ e }^{ -bx }+B\)  where A, B and b are constant to be determined.

At  \({ d }_{ s }(0)={ d }_{ e }\)  space is compressed, its space density is  \({d}_{s}\),  on surface of earth. And  \({ d }_{ s }(x\rightarrow \infty )={ d }_{ n }\)  where at long distance, space is relaxed and the corresponding space density is \({d}_{n}\).

We have,

\({ d }_{ s }(x)={ e }^{ -bx }({ d }_{ e }{ -d }_{ n })+{ d }_{ n }\) ----(1)

Then we let the inverse relationship between time speed squared  \({v}^{2}_{t}\)  and space density,  \({ d }_{ s }(x)\)   to be,

\({v}_{t}^{2}=C-D{ d }_{ s }(x)\)   where  \(C, D\)   are to be determined.

We know that as  \(x\rightarrow \infty, { d }_{ s }(x)\rightarrow{ d }_{ n }\)  where space is relaxed and time speed is \(c\),

\({v}_{t}^{2}={c}^{2}\),  \({ d }_{ s }(x)={ d }_{ n }\)

So,

\(C={c}^{2}+D{d}_{n}\)    then,

\({v}_{t}^{2}={c}^{2}-D({ d }_{ s }(x)-{d}_{n})\)

Differentiating with respect to time,

\(2{v}_{t}\cfrac{d{v}_{t}}{dt}=-D\cfrac{d({d}_{s}(x))}{dx}\cfrac{dx}{dt}=-D\cfrac{d({d}_{s}(x))}{dx}v_s\) ---(2)

But from the energy equation,

\(2{v}^{2}_{t}+{v}^{2}_{s}={c}^{2}\) differentiating it

\(4{v}_{t}\cfrac{d{v}_{t}}{dt} + 2{v}_{s}\cfrac{d{v}_{s}}{dt}=0\), since \(\cfrac{d{v}_{s}}{dt}=g\)

\(2{v}_{t}\cfrac{d{v}_{t}}{dt} = -g.{v}_{s}\)    substitute into (2)

and so,

\(g=D.\cfrac{d({d}_{s}(x))}{dx}\)

From (1), differentiating with respect to x,

\(\cfrac{d({d}_{s}(x))}{dx}=-b{e}^{-bx}({d}_{e}-{d}_{n})\) subsitute into the above we have,

\(g=-D({d}_{e}-{d}_{n}).b{e}^{-bx}\)

when  \(x=0\),    \(g=-g_o\)

\(g_o=\cfrac{G_o}{r^2_e}=D({d}_{e}-{d}_{n}).b\)

\(g=-g_o{e}^{-bx}=-\cfrac{G_o}{r^2_e}{e}^{-bx}\)

And if  we consider

\(\int^{\infty}_0{g}dx=\cfrac{G_o}{r_e}=\int^{\infty}_0{\cfrac{G_o}{r^2_e}{e}^{-bx}}dx\)

\(\cfrac{G_o}{r_e}=\cfrac{G_o}{r^2_e}[^{\infty}_0-{e}^{-bx}\cfrac{1}{b}]\)

\(r_e=\cfrac{1}{b}\)

\(b=\cfrac{1}{r_e}\)

So,

\(g=-g_oe^{-\cfrac{x}{r_e}}=-\cfrac{G_o}{r^2_e}{e}^{-\cfrac{x}{r_e}}\)

This expression is based on compression of free space, in a exponential manner.