What is the Drake equation and explain it significance.?

Answer 1

The Drake equation provides an estimate of the number of alien civilizations based on several critical factors such as the average number of planets that can potentially support life.

Unfortunately, we don't currently know what the value of these factors are so it's all guesswork at this point.

But if you consider that there are about 10^24 stars in the Universe by present estimates, if one in a billion have at least one planet that could support life, that leaves at least one billion planets that could support life.