Give 2 reasons y elliptical galaxies are considered to be older & more evolved than spiral galaxies.
They are considered to be older because they have little instellar matter and because they rarely form new stars like the other galaxies do. They seem to be more evolved than the spiral galaxies because they actually are thought to form within the clusters. The spiral galaxies consist of older stars in the center cluster.
Please tell me if this is good; more info would be appreciated, thanks
IT is ok, but one thing is the color of the stars is telling: clusters consist of yellow, red stars, not the hot blue stars. That in itself indicates an older system.
Yes, your answer is correct. Elliptical galaxies are considered to be older and more evolved than spiral galaxies due to two main reasons.
1. Lack of interstellar matter: Elliptical galaxies have little to no interstellar matter, which means they have exhausted their gas and dust reserves. This indicates that they have already formed most of their stars and are not actively creating new ones. In contrast, spiral galaxies contain abundant interstellar matter, allowing for ongoing star formation.
2. Formation within clusters: It is believed that elliptical galaxies form within galaxy clusters. The process of galaxy formation is more complex within clusters, involving interactions and mergers between galaxies. This suggests that elliptical galaxies have undergone more interactions and mergers, leading to their more evolved and mature structure.
Furthermore, elliptical galaxies tend to have round or elongated shapes, lacking the well-defined spiral arms found in spiral galaxies. The majority of stars in elliptical galaxies are older, metal-poor, and red in color. In contrast, spiral galaxies often have a mixture of old and young stars, and their spiral arms contain regions of active star formation.
These additional details should enhance your understanding of why elliptical galaxies are considered older and more evolved compared to spiral galaxies.
Your explanation touches on a couple of key points, but let me provide you with some additional information to further clarify why elliptical galaxies are considered to be older and more evolved than spiral galaxies.
1. Stellar Population: One reason elliptical galaxies are thought to be older is because they predominantly consist of older stars. These galaxies have used up most of their gas and dust reservoirs that are necessary for the formation of new stars. In contrast, spiral galaxies have an ongoing process of star formation, as they still possess significant amounts of interstellar matter to support it.
2. Lack of Structure: Elliptical galaxies have a smooth, spheroidal shape with no distinct spiral arms or disk structure. This lack of structure is a result of violent mergers and interactions with other galaxies, which have disrupted their original disk-like shape. These interactions and mergers are indicative of a more complex evolutionary history compared to spiral galaxies, which tend to retain their well-defined spiral arms and disk structure.
3. Cluster Environment: Elliptical galaxies are frequently found in dense galaxy clusters, where interactions and mergers among galaxies are more common. They are thought to have formed through a process called hierarchical merging, where smaller galaxies merge together to form larger elliptical galaxies. This suggests that elliptical galaxies have undergone more interactions and have had more time to evolve and merge with other galaxies than spiral galaxies, which are often found in less dense regions of the universe.
So, in summary, the main reasons why elliptical galaxies are considered to be older and more evolved than spiral galaxies are the depletion of their gas and dust reservoirs for star formation, their lack of structure due to violent interactions and mergers, and their tendency to form within dense galaxy clusters where mergers are more frequent.