Question

What evidence supports the idea that a collision between two spiral galaxies might lead to the creation of a single elliptical galaxy?

A) observations of some elliptical galaxies surrounded by shells of stars that probably formed from stars stripped out of smaller galaxies
B) the fact that elliptical galaxies dominate the galaxy populations at the cores of dense clusters of galaxies
C) observations of some elliptical galaxies with stars and gas clouds in their cores that orbit differently from the other stars in the galaxy
D) observations of giant elliptical galaxies at the center of dense clusters that may have grown by consuming other galaxies
E) all of the above

Answer 1

The idea that a collision between spiral galaxies can create an elliptical galaxy is supported by the observation of star shells around ellipticals, the composition of galaxy clusters, differently orbiting cores, and giant ellipticals that have likely grown through mergers.

Step-by-step explanation:

Evidence that supports the idea that a collision between two spiral galaxies might lead to the creation of a single elliptical galaxy includes:

• Observations of some elliptical galaxies surrounded by shells of stars, which likely formed from stars stripped out of smaller galaxies.
• The dominance of elliptical galaxies in the populations at the cores of dense galaxy clusters.
• The existence of elliptical galaxies with stars and gas clouds in their cores orbiting differently from other stars in the galaxy, suggesting a complex formation history.
• Observations of giant elliptical galaxies at the centers of dense clusters, which may have grown by merging with or consuming other galaxies, implying a history of collisions and mergers.

These observations, when considered together, point to galactic mergers as a significant process in the evolution of galaxies, with spiral galaxies potentially merging to form the more massive elliptical galaxies observed today.