Time between civilizations. suppose that there are 100 billion stars in the milky way galaxy, that 1 in 1 million stars gets a civilization at some point, and that these civilizations have arisen at random times over the past 5 billion years. on average, how much time separates the rise of one civilization in the galaxy from the rise of the next? based on your answer, should we expect to make radio contact with another civilization that is either at or below our own current level of technological development?

We are alone living in this universe. So far we have not yet detected any civilization other than Earth. But assume that the possibility of having a civilization in a star in the Milky Way Galaxy over 5 billion years is 1 in million. We are going to find the time separation of each civilization if our galaxy has 100 billion stars.

The number of stars in the galaxy  

The possibility of stars having civilization

It is not possible to make radio contact with another civilization, because our technology did not come to this far yet.

the answer is:

a. a closed question always has yes or no​ answers, whereas an open question is a​ free-response question.