The Drake equation is one of astronomy’s most famous attempts to answer the question: Are we alone? It asks not just about any life, but the top shelf stuff: intelligent life with the ability to communicate with beings outside their planet. Microbes or floating sentient clouds don’t make the cut. We want aliens that will talk to us.
To be clear, this means there could be life out there in the universe that the Drake equation would discount. But in terms of knowing how likely we are to receive alien signals, it’s a great way to organize our questions. It starts from a sky-high view of the necessities for life and then zooms in, each component of the equation narrowing or broadening the possibilities (and getting harder to determine).
The equation asks first about the average rate of star formation in the galaxy. This doesn’t sound particularly applicable to life, ...
