<p>WASHINGTON - In ``Star Wars,'' Darth Vader rules the ``dark side'' of a fantasy universe. In real life, astronomers are exploring the ``dark side'' of our own universe. They find it a mystifying place.</p>
<p>According to a batch of new reports published in a special ``Welcome to the Dark Side'' issue of the journal Science, most of the cosmos cannot be seen, even with the most powerful telescopes. All but a tiny fraction of creation consists of two exotic, invisible ingredients called ``dark energy'' and ``dark matter.''</p>