title: How to convert local time string to UTC?
body: <p>How do I convert a datetime <em>string in local time</em> to a <em>string in UTC time</em>?</p>
  
  <p>I'm sure I've done this before, but can't find it and SO will hopefully help me (and others) do that in future.</p>
  
  <p><strong>Clarification</strong>:  For example, if I have <code>2008-09-17 14:02:00</code> in my local timezone (<code>+10</code>), I'd like to generate a string with the equivalent <code>UTC</code> time: <code>2008-09-17 04:02:00</code>.</p>
  
  <p>Also, from <a href="http://lucumr.pocoo.org/2011/7/15/eppur-si-muove/" rel="noreferrer">http://lucumr.pocoo.org/2011/7/15/eppur-si-muove/</a>, note that in general this isn't possible as with DST and other issues there is no unique conversion from local time to UTC time.</p>