What mechanisim in the vicinity of a star gives us a hint of the precence of a black hole as a companion to the stars?
A) The light from the companion starr shows extreme redshift because of the gravitational field of the black hole.
B] The star periodically disappears from the view point of earth during its eclipses by the black hole as the two objects orbit each other.
C[ the space near the stars darken indicating that the black hole prevents the light from distant objects from reaching earth.
D[ Gas from the star, falling in toward a black hole, is compressed to very high densities and temperatures so that it emitsan intense and rapidly fluctuating flux of x rays.