... APOD: 2004 August 24- Supply Ship Approaches the Space Station . ... Earth at Night . ... Nearly 400 years ago astronomer Johannes Kepler observed comet tails blown by a solar breeze and suggested that vessels might likewise navigate through space using appropriately fashioned sails. ... Lightning on Earth . ... It is known that charges slowly separate in some clouds causing rapid electrical discharges (lightning), but how electrical charges get separated in clouds remains a topic of much research. ...