Glenn Rebka checking a detector in the basement of Jefferson laboratory, at the bottom of the 74 foot tower. He is using a telephone to speak to Robert Pound, who is in the attic at the top of the tower.

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1. Robert McNees (mcnees@mastodon.social)'s status on Saturday, 09-Mar-2024 16:36:35 UTC Robert McNees

   in reply to

   That is precisely what Pound and Rebka needed, as they sent photons up and down a 74 foot tower and tried to measure a tiny fractional decrease and increase, respectively, in their frequency.

   Here is Robert Pound seated at the top of the tower, which stretched from the attic to the basement of Harvard's Jefferson laboratory. He is speaking on the phone to Glenn Rebka, stationed at the bottom.

   Images: Harvard University News Office