Description:
------------
Checked the number of seconds since the epoch using the code shown in the 'Test 
script' section below. There is a discrepancy when number of seconds = 
10000000000 in that time goes backwards, i.e. 1973 to 2001 to 2014 to 2008.

Number of seconds since epoch = 1, date = 1 January 1970 01:00:01 
Number of seconds since epoch = 10, date = 1 January 1970 01:00:10 
Number of seconds since epoch = 100, date = 1 January 1970 01:01:40 
Number of seconds since epoch = 1000, date = 1 January 1970 01:16:40 
Number of seconds since epoch = 10000, date = 1 January 1970 03:46:40 
Number of seconds since epoch = 100000, date = 2 January 1970 04:46:40 
Number of seconds since epoch = 1000000, date = 12 January 1970 14:46:40 
Number of seconds since epoch = 10000000, date = 26 April 1970 18:46:40 
Number of seconds since epoch = 100000000, date = 3 March 1973 10:46:40 
Number of seconds since epoch = 1000000000, date = 9 September 2001 03:46:40 
Number of seconds since epoch = 10000000000, date = 7 September 2014 06:50:08 
Number of seconds since epoch = 100000000000, date = 11 July 2008 06:56:32 

Test script:
---------------
<?php
  for ($i=0; $i<12; $i++) {
    $numberOfSecondsSinceEpoch = pow(10,$i); 
    $date = date("j F Y H:i:s", $numberOfSecondsSinceEpoch);
    echo "Number of seconds since epoch = $numberOfSecondsSinceEpoch, date = $date <br />";
  } 
?>