Question

question 2
1 pts
we estimate the mass of the galaxy by observations of its _______ curve.

• temperature
• luminosity
• spiral
• density
• rotation

Explanation:

The rotation curve of a galaxy shows how the orbital speed of stars or gas in the galaxy depends on their distance from the center. By analyzing this curve, we can estimate the mass of the galaxy (using gravitational laws like \(v = \sqrt{\frac{GM}{r}}\), where \(v\) is the orbital speed, \(G\) is the gravitational constant, \(M\) is the mass enclosed within radius \(r\)). Temperature curve relates to thermal properties, luminosity curve to brightness, spiral is a galaxy type, and density curve to mass - per - unit - volume distribution (but not directly used in the standard mass - estimation method like rotation curve).

Answer:

rotation