What is Drake equation? I was reading an article on aliens, where I found something called Drake equation. I tried to understand it, but just couldn't get it in my head, as I belong to class 11. So, can anyone explain me it in simple language, in terms that I'm capable of understanding? 
 A: Simply put, it is: how many aliens could we meet?
More specifically: The Drake Equation is a way of predicting how many intelligent species there might be in the universe and the likelihood of them contacting us.
There are a lot of things that can change the number of aliens we can expect to find.  So we use what we know about the universe so far and keeping multiplying the various factors to get some sort of idea (no one knows if it is accurate, but it is nice to have some sort of idea).
The factors include: 


*

*How many stars are there? (because we think all life would need to be
near a star).

*How many planets are there? (because life obviously needs some place
to live and it can't live on a star)

*How many of those planets have water and air? (i.e. habitable
planets)

*How many of those airy, watery planets contain aliens?

*How many of those aliens are clever?

*How many clever aliens invent radio or some other way of
communicating?


And most importantly:


*

*How long do they try to communicate? (because if they blow themselves
up in a war or give up trying to say hello then they are never going
to be found by our telescopes).


The universe has been around such a long time that it's possible aliens nearby have lived and died long ago and we are going to find younger aliens somewhere else, but not for millions of years. etc. etc.
Of course, we can't know the answers to some of these questions, but we do know the answers to others and we get more accurate and more information all the time.  Eventually we'll have enough info to make an educated guess and that will be an exciting time indeed!
