General Relativiy - Definition of a test body?

[binbagsss]

I know it follows a geodesic in space-time, but is it not being able to bend space-time itself, part of the definition?

When I google i just find 'follows a geodesic in space-time'. I thought that it also should not bend space-time itself - but this isn't included in the definitions I've found...


Thanks, greatly appreciated !

 

[ShayanJ]

I think that's part of the definition. Like the test charge used in electrostatics.
Because if we consider the test body's gravitational field, then the gravitational self-interaction will cause the geodesic to be different from the geodesic of the space-time we were considering.