Respuesta :
Answer:
Explanation:
The fact that the outer portion of the rotation curve of a galaxy is mainly flat indicates the presence of dark matter.
Rotation curves describe the rotational velocity of stars or gas in a galaxy as a function of their distance from the galactic center. In a typical galaxy, the expected behavior would be for the rotational velocity to decrease as you move farther from the center. However, observations have shown that in many galaxies, the outer portion of the rotation curve remains relatively constant or flat, indicating that the rotational velocity does not decrease as expected.
This unexpected behavior can be explained by the presence of additional mass in the form of dark matter. Dark matter is an invisible and elusive form of matter that does not interact with light or other electromagnetic radiation, making it difficult to directly detect. However, its gravitational effects can be observed through its influence on the motion of visible matter, such as stars and gas.
The flat rotation curve suggests that there is more mass in the outer regions of the galaxy than can be accounted for by visible matter alone. This additional mass is attributed to dark matter, which provides the gravitational pull necessary to keep the outer portions of the galaxy rotating at higher velocities. Therefore, the flat rotation curve is evidence for the existence of dark matter in galaxies.
