•Question 12  (1 point) The black hole in the
 center of our Milky Way galaxy
 seems to be about 2.6 million times the mass of the sun according to the text.  (Recently updated to 3.6 million solar masses, so use the new value here.)  What is the radius of its event horizon? Think about how big this is compared to
 other astronomical objects
 (e.g., Earth, the sun, the solar system, the distances between stars).
 •a.About a billion km.
 •b.About 5.5 thousand km.
 •c.About 5.5 million km.
 •d.About 11 thousand km.
 •e.About
 11 million km.
 •
 •Use the
 equation for the even horizon radius, R = 2GM/C2 and plug in the right numbers.  Or remember that the horizon for a solar mass black hole is 3 km, and multiply by
 3.6 million.
 •