Blink from a remote world

摘要

Sometimes, a blink is more informative than a steady look. This is certainly the case when it comes to stellar occultations, events that occur when a planetary body hides a star as it moves across the sky. More than being a mere curiosity, such events provide a wealth of information about the occulting body -more so than direct images of it. For instance, stellar occultations have proved a powerful tool in discovering planetary rings, probing remote atmospheres at microbar pressure levels and measuring sizes at kilometric accuracies for bodies located hundreds of millionsrnof kilometres from Earth. On page 897 of this issue, Elliot and colleagues' report the first detection of a stellar occultation by a small object orbiting beyond the giant planet Neptune. The object is 2002 TX_(300) (also known as KBO 55636), which lurks at a distance of more than 6 billion kilometres from our planet.