My parents in Dallas watched the shuttle re-entry Friday night and report that it was "one of the most spectacular things we have ever seen". They say that it looked like a slowly moving fireball, with a brightly glowing persistent "contrail" left behind it. So persistent, in fact, that the trail in the West was just beginning to fade from view as the shuttle itself disappeared in the East. Is the glow of the shuttle itself just from heat causing the tiles to glow by blackbody radiation, or is there more to it than that? And what causes the persistent glowing train? Air heated to a plasma recombining?