You are the leader of the international Event Horizon Telescope, a collaboration of radio astronomers who want to take a picture of the black hole at the center of the Milky Way (Sag. A*). That black hole has a mass of about 4.1 million solar masses and is about 8 kpc away. If you are observing with a radio wavelength of about 1 mm, what effective diameter of your radio interferometric array is needed in order to just resolve the diameter of the Sag. A* black hole event horizon. (Assume the black hole is non-spinning, so its diameter is twice the event horizon radius.)

You are the leader of the international Event Horizon Telescope, a collaboration of radio astronomers who want to take a picture of the black hole at the center of the Milky Way (Sag. A). That black hole has a mass of about 4.1 million solar masses and is about 8 kpc away. If you are observing with a radio wavelength of about 1 mm, what effective diameter of your radio interferometric array is needed in order to just resolve the diameter of the Sag. A black hole event horizon. (Assume the black hole is non-spinning, so its diameter is twice the event horizon radius.)