Astrophysical Jets and Theories of Gravitation

We point out that a recently discovered hydrodynamical jet formation mechanism (see work by Fryxell, Taam, & McMillan and Matsuda et al.) provides us with a tool that is capable of distinguishing between general relativity and bimetric general relativity. It is for the first time that such a large-scale phenomenon as the mere presence or absence of relativistic jets can distinguish between theories of gravitation. The present observational situation seems to favor general relativity over bimetric general relativity.