Yes, it's possible: that's generational garbage collection. But last I heard, Google decided writing a modern GC was too complicated.
They're probably right, because Google doesn't need it. But for everyone else who decided to use a language designed to solve Google's fairly-unique problems as if it were a general-purpose language: that kind of sucks, doesn't it?
The fact seems to be that the go team is not so well funded as it seems. Go is not Google's language in the sense C# is MS' language or Java was Sun language.
