Geodesic Eq: Deriving 2nd Term on RHS

In summary, the geodesic equation can be derived by parameterizing the curve with a time coordinate instead of a space coordinate and looking at how the equation transforms under this change. This method does not involve working with the metric directly. The second term on the right hand side of the equation can be obtained by considering the transformation of the geodesic equation under this variable substitution and keeping in mind the relationship between the time and space coordinates.
  • #1
peterpang1994
37
0
As the geodesic equation in a form of
ed2e808ce2b6aa1859eb947f21f23ec0.png

is quite familiar for me. But I still cannot derive it in terms of time coordinate parameter;
a82eae864b04bc27b468fc0becfabe9d.png

I can't get the second term on the right hand side
what I can get is
½{d[lngαβ(dxα/dt)(dxβ/dt)]/dt}dxμ/dt

How can I obtain that term?
 
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  • #2
I suggest you do not work in terms of the metric. The equation follows directly from the variable substitution to parameterise the curve with ##t## instead of ##s## and looking at how the geodesic equation transforms under this change. Keep in mind that
$$
\frac{d^2 t}{ds^2} = - \Gamma^0_{\alpha\beta} \dot x^\alpha \dot x^\beta .
$$
 
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Related to Geodesic Eq: Deriving 2nd Term on RHS

What is a geodesic equation?

A geodesic equation is a mathematical expression used to describe the path of a free particle in a curved space. It is derived from the principles of general relativity and is used to understand the motion of objects in the presence of gravity.

What is the RHS in the geodesic equation?

The RHS (right-hand side) in the geodesic equation represents the effects of curvature on the motion of a particle. It includes terms such as the Christoffel symbols, which describe the curvature of the space, and the velocity of the particle.

What is the 2nd term on the RHS in the geodesic equation?

The 2nd term on the RHS in the geodesic equation is the acceleration term. It takes into account the acceleration of the particle due to the curvature of space. This term is essential for predicting the motion of objects in a gravitational field.

How is the 2nd term on the RHS derived?

The 2nd term on the RHS is derived using the principle of least action, which states that the actual path taken by a particle is the one that minimizes the action (a measure of the energy) along its path. By applying this principle to the geodesic equation, the 2nd term on the RHS can be derived.

Why is the 2nd term on the RHS important in the geodesic equation?

The 2nd term on the RHS is important because it takes into account the effects of curvature on the motion of a particle. Without this term, the geodesic equation would not accurately describe the motion of objects in a curved space, such as planets orbiting around a star or satellites moving in Earth's gravitational field.

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