Sgr A* is believed to be the center of the Milky Way galaxy because
I. It lies in the general direction of the center of the galaxy based on observations of globular clusters in the plane of the Milky Way.
II. Long wavelength dust penetrating images show it to be a region crowded with stars
III. Orbits of stars around it indicate a mass several million times that of the Sun within a volume a few light hours in size
IV. Radio observations show it is a concentrated source at the center of swirling clouds of gas

Question

Quizplus · Accepted Answer

All four statements provide evidence for Sgr A* being the center of the Milky Way galaxy. I and IV suggest its location and gravitational influence, II illustrates its starry nature, and III confirms its mass. All of the statements are true and provide evidence for Sgr A* being the center of the Milky Way galaxy. Statement I is based on observations of globular clusters, which are collections of stars that orbit the center of the galaxy. Statement II is supported by long wavelength dust penetrating images, which reveal a dense concentration of stars in the region of Sgr A*. Statement III is confirmed by observing the orbits of stars around Sgr A* and measuring their speeds, which indicate that a large amount of mass is present within a small volume. Finally, statement IV is based on radio observations, which show Sgr A* as a strong source of radiation located at the center of swirling clouds of gas.

Sgr A* Is Believed to Be the Center of the Milky