stardate.php

<?php

class Stardate {
  # Ported from https://github.com/pioz/stardate/blob/master/lib/stardate.rb
  
  private static $year_0 = 2323;
  private static $year_duration = 365.2425;
  
  public static function date_to_stardate($date) {
    # days since the beginning of the year
    $days = $date->format('z'); 
    
    # seconds since the beginning of the day
    $seconds = ((int)$date->format('G')*60*60) + ((int)$date->format('i')*60) + (int)$date->format('s');
    
    return (($date->format('Y') - self::$year_0) + $days / self::$year_duration + $seconds / (self::$year_duration * 24 * 3600)) * 1000;
  }
}

$date = new DateTime('2413-11-26 18:35:34 +0100');
echo Stardate::date_to_stardate($date)."\n";