The observable universe is
A)the minor portion of the universe we can observe.
B)the part of the universe that is within the visible electromagnetic spectrum.
C)part of the universe visible to the unaided eye.
D)about 100 billion light years across.

Question

Quizplus · Accepted Answer

The observable universe refers to the portion of the universe we can observe, which is limited by the distance light has had time to travel since the Big Bang. This means that there may be parts of the universe beyond our observable horizon that we cannot see, making choice B incorrect. While some objects in the observable universe may be visible to the unaided eye, this is not a defining characteristic of the observable universe, making choice C incorrect. The size of the observable universe is difficult to measure precisely, but it is estimated to be around 93 billion light years in diameter, making choice D incorrect. Therefore, the best choice is A.

The Observable Universe Is