““The official record for the fastest manmade object is the Helios 2 probe, which reached about 70 km/s in a close swing around the Sun. But it’s possible the actual holder of that title is a two-ton metal manhole cover. The cover sat atop a shaft at an underground nuclear test site operated by Los Alamos as part of Operation Plumbbob. When the 1-kiloton nuke went off below, the facility effectively became a nuclear potato cannon, giving the cap a gigantic kick. A high-speed camera trained on the lid caught only one frame of it moving upward before it vanished—which means it was moving at a minimum of 66 km/s. The cap was never found.””
![“I looked for it [heavy hydrogen, deuterium] because I thought…” quote by Harold Urey](https://sms4smile.com/quotes/img-quotes/78e/harold-urey-42546_application_i-looked-for-it-heavy-hydrogen-deuterium_1237859.jpg)
