What is the best evidence for the existence of an extremely massive black hole at the center of the Milky Way?

• A. The observation of supernova explosions near the center of the Milky Way
• B. The detection of strong radio waves coming from the center of the galaxy
• C. The observation of stars orbiting rapidly around an invisible point, indicating a massive compact object
• D. The presence of large amounts of interstellar dust near the galactic center

Answer: (C)

Verified step by step guidance

1. Understand that the question asks for the best evidence supporting the existence of an extremely massive black hole at the center of the Milky Way galaxy.
2. Recall that a black hole itself cannot be observed directly because it emits no light; instead, its presence is inferred from its gravitational effects on nearby objects.
3. Recognize that observing stars orbiting rapidly around an invisible point suggests a very massive and compact object exerting strong gravitational pull, which is consistent with a black hole.
4. Contrast this with other options: supernova explosions and radio waves indicate energetic phenomena but do not directly prove a massive compact object; interstellar dust presence does not confirm a black hole either.
5. Conclude that the key evidence is the precise measurement of stellar orbits near the galactic center, which allows astronomers to calculate the mass and size of the central object, strongly indicating a supermassive black hole.