xkcd feeds.twtxt.net Sun, Apr 28 22:00 (29w ago) Doppler Effect The Doppler effect is a mysterious wavelength-shifting phenomenon which seems to primarily affect sirens, which is why the 🚨 emoji is red. DownloadThe Doppler effect is a mysterious wavelength-shifting phenomenon which seems to primarily affect sirens, which is why the 🚨 emoji is red. ⌘ Read more ⤋ Read More Yarn
