The latest and most definitive measurement puts the mass of that black hole at 3,600,000 times the mass of the Sun.1
The Milky Way Galaxy’s central black hole by itself is not dangerous to life on Earth. It is too far away to pose a significant source of gravitational disturbance. What does pose a risk for Earth life, though, is the gas, dust, and stars that swirl into the maw of the black hole. As this material nears the event horizon of the black hole, the black hole’s intense gravity causes up to ten percent of the mass of this material to be converted into deadly radiation. Fortunately, for life on Earth, especially the more radiation-sensitive advanced life, the deadly radiation doesn’t prove lethal. The solar system maintains an orbit about the center of the Milky Way Galaxy (MWG) that keeps it within the plane of the Galaxy where a thin dust layer blocks out almost all the radiation emanating from the central black hole.
As enormous as the MWG’s central black hole measures to be, it is tiny by comparison with other comparably sized spiral galaxies. (For a number of reasons advanced life is possible only within a medium-sized spiral galaxy2.) The MWG’s sister galaxy, the Andromeda Galaxy, possesses a central black hole that weighs in at 140,000,000 times the mass of the Sun.3 That’s 39 times the mass of the MWG’s central black hole!
The greater the mass of a galaxy’s central black hole the greater the amount of deadly radiation that will arise from material being sucked into it. In the case of the Andromeda Galaxy the radiation problem is compounded. Recent observations of the nucleus of the Andromeda Galaxy show that huge reservoirs of gas exist in the immediate vicinity of the central black hole.4 These reservoirs imply that far more material is spiraling into the event horizon of the Andromeda Galaxy’s central black hole than is the case for the MWG’s central black hole. So, not only does more deadly radiation arise from the Andromeda Galaxy’s central black hole because of its greater mass but also because of its greater supply of infalling material.
As noted in a previous edition of Today’s New Reason To Believe, for medium-sized spiral galaxies the Andromeda Galaxy is typical whereas the MWG is rare. The MWG has suffered no major merging events with other galaxies over the past ten billion years. Consequently, its central black hole is relatively tiny and the amount of gas available for feeding its central black hole remains small. The unique characteristics of the MWG’s central black hole provides yet one more set of scientific evidences for the supernatural, super-intelligent design of the Milky Way Galaxy for the benefit of advanced life.