tag:blogger.com,1999:blog-627288822362203855.post7201422485747965958..comments2020-04-29T08:55:29.230-05:00Comments on Cosmic Yarns: The Elements Nobody Talks About: IridiumRobert Scherrerhttp://www.blogger.com/profile/17341214577362261827noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-627288822362203855.post-87295156246666094162016-07-19T15:08:52.709-05:002016-07-19T15:08:52.709-05:00Oh I see! Thanks so much for the follow up. Also, ...Oh I see! Thanks so much for the follow up. Also, mind blown :)Justinhttps://www.blogger.com/profile/04138857652921543796noreply@blogger.comtag:blogger.com,1999:blog-627288822362203855.post-9576560839631286792016-07-19T14:55:38.160-05:002016-07-19T14:55:38.160-05:00Start with the speed of light. If you define it to...Start with the speed of light. If you define it to have a certain known value in meters per second, then a unit of time (seconds) can be converted exactly into a unit of distance (meters). Now remember that Planck's constant has units of energy times time. So if you define it to have a fixed value, then you can convert you unit of time into a unit of energy. But E = mc^2, and we've already defined c to have a known value, so now we convert our unit of energy into a unit of mass. Robert Scherrerhttps://www.blogger.com/profile/17341214577362261827noreply@blogger.comtag:blogger.com,1999:blog-627288822362203855.post-89860326517034420602016-07-19T14:49:10.492-05:002016-07-19T14:49:10.492-05:00"If we simply define Planck's constant to..."If we simply define Planck's constant to have a fixed value, then we can calculate a value for the kilogram directly in terms of the second."<br /><br />Can you elaborate? I know Planck's constant defines the minimal size of space / unit of time. How do you get to mass?Justinhttps://www.blogger.com/profile/04138857652921543796noreply@blogger.comtag:blogger.com,1999:blog-627288822362203855.post-85114615808050318692016-07-19T14:48:36.017-05:002016-07-19T14:48:36.017-05:00This comment has been removed by the author.Justinhttps://www.blogger.com/profile/04138857652921543796noreply@blogger.comtag:blogger.com,1999:blog-627288822362203855.post-79010794798836707342016-07-12T09:29:01.927-05:002016-07-12T09:29:01.927-05:00Agreed. Iridium is a much more colorful name (all ...Agreed. Iridium is a much more colorful name (all good puns should be bilingual )Kathynoreply@blogger.comtag:blogger.com,1999:blog-627288822362203855.post-51227993921893299752016-07-12T09:20:04.702-05:002016-07-12T09:20:04.702-05:00Thanks! I didn't know that. It looks like ther...Thanks! I didn't know that. It looks like there are 66 satellites in orbit, which implies the name "dysprosium satellites". I see why they stuck with iridium!Robert Scherrerhttps://www.blogger.com/profile/17341214577362261827noreply@blogger.comtag:blogger.com,1999:blog-627288822362203855.post-66379030486402505042016-07-12T09:09:21.898-05:002016-07-12T09:09:21.898-05:00I know this one!
The original plan for the satell...I know this one!<br /><br />The original plan for the satellite constellation called for 77 satellites, equal to iridium's atomic number. Ergo the name. By the time it was deployed, fewer satellites were used, but the name stuck.<br /><br />BTW Asimov's robots' positronic brains were made of a platinum-iridium alloy.Kathynoreply@blogger.com