This horn antenna was used by Harold I. Ewen and Edward M. Purcell at the Lyman Laboratory of Physics at Harvard University in 1951 for the first detection of radio radiation from neutral atomic hydrogen gas in the Milky Way at a wavelength of 21 …
We are building the largest online collection of historical markers, along with other markers that
represent significant events, people, places, and more, but we can't do it without your help. Become
a member and you'll be able to add historical markers, post comments, save favorites, check in, and
Subscribe To Our Newsletter
Keep up with everything we do — We'll deliver our newsletter to your inbox each week.