Q: I am leftover from the beginning of time. Without me and my spots, galaxies could not have formed. I’m everywhere in the cosmos, but not uniformly. My wavelengths were small, but you sense them as stretched. A spacecraft was launched decades ago to take my temperature and look for my spots. What am I, and how did this spacecraft find me?
Draft a response of no more than 250 words and email it to email@example.com for a chance to have it published in the February issue.
FLIGHT-TEST FEEDBACK: We asked you what devices had been removed from a prototype jet that led the test pilot to say the aircraft was difficult to control in certain configurations and wanted to stall sooner than it should. He assessed “a Cooper-Harper of 7 to 8” at times.
WINNER: The engineer was referring to wing vortex generators. These devices on the upper surface of a wing are used to control flow separation along the aft portion of the wing. If they are removed, the flow will separate at a lower angle of attack, and the plane would stall sooner. It would be desirable to not have vortex generators because they produce drag.
David G. Hull
AIAA associate fellow and member emeritus