how google works?

it knows the official depth of a olympic pool, the speed of light, how to replace a spark plug, it knows every email i have sent or recieved in the past 4 years, it even knows my dogs name.... So how is it that google pretty much knows everything? well, here is my guess:

Ive heard much talk of google's "secret algorithm"-the mythical code that endows google with infinite genius and practicality-and I have to think that this is the crux of how google work. In my mind, as I begin to type something into the google search bar, google is already scanning my every keystroke and referencing this information against a massive data cache of popular searches that start out similar to, or have the same words as what im typing...this then spits out many, many possible questions that I may or may not be asking... then, once ive decided on my question, and hit "search", this is when the google algorithm kicks in. google takes the words i have input, and it rapidly scans for these words across many, many websites, looking for the best fit. but google doesn't just look for websites that fit, it has a way of finding websites that both fit, and are popular, and are relevant, and are in my language...how does it do this? i cant even begin to know. it seems as if google can scan the endless vastness of the internet in its entirety in seconds; finding the good and weeding out the bad...its mind boggling. I cant believe google searches the whole internet...but in many ways that does seem to be the case. how does google do it? does it break up the internet into pre-determined piece, that are then individually, and simultaneously searched? does google go through each corner of the web, site by site? or does google simply know everything? i will probably never know.