title: Difference between time () and new MongoDate()?
body: <p>Is there a difference between using PHPs <code>time()</code> and using <code>new MongoDate()</code>?
  I need to store created_at and updated_at dates for each documents in by mongoDB collection
  so that I can query them by date (for example documents updated last week).</p>
  
  <p>From what I can see time() and new MongoDate() produces the same result?</p>