<p></p> <p>Auroras are the most visible manifestation of the Sun’s effect on Earth, but many aspects of these spectacular displays are still poorly understood. Thanks to ESA’s Cluster and NASA’s Image
<p style="text-align: center;"></p> <p>The placid appearance of the Sun’s surface belies a hot fireball of plasma in constant turmoil. A granular network invisible to the naked eye pervades the solar disc,
<p>A favorite theme of science fiction is “the portal”–an extraordinary opening in space or time that connects travelers to distant realms. A good portal is a shortcut, a guide,
<p>NASA’s Voyager probes are truly going where no one has gone before. Gliding silently toward the stars, 9 billion miles from Earth, they are beaming back news from