Which parameter is now thought to be vital in the evolution of a pregalactic gas cloud into an elliptical rather than a spiral galaxy?
A) The presence of other evolving galaxies nearby
B) The initial rate of star birth
C) The presence of supernova explosions to trigger star birth within the galactic cloud
D) The presence of a black hole around which the galaxy can form

Question

Quizplus · Accepted Answer

Studies have shown that the initial rate of star birth in a pregalactic gas cloud is crucial in determining whether it evolves into an elliptical or a spiral galaxy. Elliptical galaxies form from gas clouds with high initial rates of star formation while spiral galaxies form from gas clouds with lower rates of star formation. The presence of other galaxies, supernova explosions, or black holes may play a role in the evolution of a galaxy, but they are not considered to be vital parameters in determining its overall shape.

Which Parameter Is Now Thought to Be Vital in the Evolution