Earth observations taken from orbiter Discovery during STS-91 mission

STS091-713-061 (2-12 June 1998) --- The vertical stabilizer of the Space Shuttle Discovery runs through this Atlantic Ocean image made from its crew cabin. Many sets of internal waves are seen in the 70mm frame traveling through an area off the Atlantic coast of Nova Scotia, Canada. There are seven sets that run perpendicular to each other. Internal waves are tidally induced and travel below the surface of the ocean along a density change which occurs often around 150 feet deep. According to NASA scientists studying the STS-91 collection, the waves are visible because, as the wave action smoothes out the smaller waves on the surface, the manner in which the sun is reflected is changed.