How has the fraction of galaxies with irregular morphologies evolved from 4 billion years ago to the present epoch?
A) About 10 percent of today's galaxies are peculiar, whereas 4 billion years ago more than half the galaxies were peculiar.
B) The fraction has remained at 50 percent over the last 4 billion to 5 billion years.
C) At the present epoch there are far more interacting galaxies than when the universe was about 9 billion to 10 billion years old.
D) The fraction has remained at 10 percent over the last 4 billion to 5 billion years.
E) There are no peculiar galaxies today, whereas 4 billion years ago they comprised nearly 10 percent of galaxies.

Question

Quizplus · Accepted Answer

4 billion years ago, the universe was more chaotic, with more interactions and mergers, leading to a higher fraction of peculiar galaxies. Over time, galaxies have settled into more regular forms, reducing the fraction of irregular morphologies.

How Has the Fraction of Galaxies with Irregular Morphologies Evolved