11. Many efforts have been made to detect gravity waves directly, but all have failed. 12. This contrasts with non-linear surface gravity waves , which have sharp crests and flat troughs. 13. Gravity waves have teased physicists for decades, because they have announced their presence only indirectly.14. During this time, Lindzen published some research on gravity waves , as well as Hadley circulations. 15. The quest for gravity waves goes back many years. 16. Gravity waves should occur whenever a mass is accelerated.17. It is designed to look not for light or radio waves, but for gravity waves . 18. An internal wave is a gravity wave that moves along density stratification within the ocean. 19. Image : Wave phase . gif See Gravity wave . 20. In practice, the quest is complicated by the fact that gravity waves are very weak.
