Classical Gravity
The easiest case for the application of a test particle arises in Newtonian gravity. The general expression for the gravitational force between two masses and is:
where and represent the position of each particle in space. In the general solution for this equation, both masses rotate around their center of mass, in this specific case:
In the case where one of the masses is much larger than the other, one can assume that the smaller mass moves as a test particle in a gravitational field generated by the larger mass, which does not accelerate. By defining the gravitational field as
with as the distance between the two objects, the equation for the motion of the smaller mass reduces to
and thus only contains one variable, for which the solution can be calculated more easily. This approach gives very good approximations for many practical problems, e.g. the orbits of satellites, whose mass is relatively small compared to that of the earth.
Read more about this topic: Test Particle
Famous quotes containing the words classical and/or gravity:
“Culture is a sham if it is only a sort of Gothic front put on an iron building—like Tower Bridge—or a classical front put on a steel frame—like the Daily Telegraph building in Fleet Street. Culture, if it is to be a real thing and a holy thing, must be the product of what we actually do for a living—not something added, like sugar on a pill.”
—Eric Gill (1882–1940)
“Here I sit down to form characters. One I intend to be all goodness; All goodness he is. Another I intend to be all gravity; All gravity he is. Another Lady Gish; All Lady Gish she is. I am all the while absorbed in the character. It is not fair to say—I, identically I, am anywhere, while I keep within the character.”
—Samuel Richardson (1689–1761)