Which is a mark of a galaxy formed by collapse?(1 point)
Responses
abundant gas and dust
same age stars
uniformly young stars
a mix of young and old stars
abundant gas and dust
The correct response is: abundant gas and dust.
The mark of a galaxy formed by collapse is the presence of a mix of young and old stars. To understand this, we need to know a bit about galaxy formation.
Galaxies form through various processes, such as gravitational collapse or merging of smaller galaxies. When a galaxy forms through collapse, it starts with a cloud of gas and dust. Over time, this cloud of gas and dust collapses under its own gravity, forming stars. The collapse process occurs over an extended period, during which both young and old stars are formed.
Abundant gas and dust are commonly found in galaxies, regardless of their formation mechanism. Gas and dust serve as the building blocks for new stars and provide the material necessary for the growth and evolution of galaxies. Therefore, the presence of abundant gas and dust is not a distinguishing mark of a galaxy formed by collapse.
Similarly, having uniformly young stars is not necessarily a mark of a galaxy formed by collapse. Although new stars are continually formed in galaxies through various processes, galaxies can also have old stars that were formed in earlier stages of their formation.
On the other hand, a mix of young and old stars is characteristic of a galaxy formed by collapse. Over time, the collapse of the gas and dust cloud leads to the formation of both young, hot, and massive stars, as well as older, cooler, and less massive stars. The presence of this variety of stellar populations indicates that the galaxy has undergone a collapse process rather than being formed by other mechanisms.
So, among the given options, "a mix of young and old stars" is the mark of a galaxy formed by collapse.