Scoring and relevance, old article gets higher score then the new one

I'm using UnifiedSearch, a simple search like this:

SearchClient.Instance
    .UnifiedSearch()
    .For(query)

I know that this example is stupid and not a real world example but it's an easy way to reproduce the error.

I have two identical pages, except that one page is older (Document.PublishDate and Document.UpdateDate) and of course the url segment is different. The older page gets a higher score which must be wrong? I tried to boost the date but it seems like that's not possible when using UnifiedSearch? Is it possible to alter the default behavior so new articles are rated with a higher score?

- Marcus