Figure 1:
The black hole in the Galactic Center - if it is one - is
big and close enough to image its event horizon, or `shadow', with
existing technology. This is argued in a paper by
Falcke, Melia, &
Agol (2000). The figure shows the appearance of the shadow of the
black hole for Sagittarius A* against the compact radio emission. The
images were calculated for the interstellar scattering and the
instrumental resolution expected for upcoming sub-mm VLBI experiments
(right: lambda=1.3mm, middle: lambda=0.6mm). In a second paper Agol
argues that the polarization properties of Sgr A* (see article) strengthen that claim.