Path: ...!weretis.net!feeder9.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail From: Jan Panteltje Newsgroups: sci.electronics.design Subject: Re: OT: sound speed depends on frequency on mars Date: Sat, 31 Aug 2024 07:31:52 GMT Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; ISO-8859-15 Content-Transfer-Encoding: 8bit Injection-Date: Sat, 31 Aug 2024 07:31:53 -0000 (UTC) Injection-Info: solani.org; logging-data="2074914"; mail-complaints-to="abuse@news.solani.org" User-Agent: NewsFleX-1.5.7.5 (Linux-5.15.32-v7l+) Cancel-Lock: sha1:a/zRANJeY4/7DR4MV758xmB7gT8= X-User-ID: eJwFwQkBA0EIA0BLfIGtHKDEv4SbgafmViQyQLBVbxgFXFvHBg6pVQyXo7z/TJvr7v3m3g7b+JIydBk1+QBtPhZm X-Newsreader-location: NewsFleX-1.5.7.5 (c) 'LIGHTSPEED' off line news reader for the Linux platform NewsFleX homepage: http://www.panteltje.nl/panteltje/newsflex/ and ftp download ftp://sunsite.unc.edu/pub/linux/system/news/readers/ Bytes: 3279 Lines: 48 On a sunny day (Fri, 30 Aug 2024 07:34:05 -0700) it happened john larkin wrote in : >On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje >wrote: > >>NASA's Mars rover Perseverance has found that sound travels much more slowly on the Red Planet than it does on Earth >>and behaves in some unexpected ways that could have strange consequences for communication on the planet. >> https://www.space.com/nasa-mars-rover-perseverance-speed-of-sound#main >> At frequencies above 240 Hertz, "the collision-activated vibrational modes of carbon dioxide molecules do not have enough >> time to relax, or return to their original state," >> the researchers said, which results in sound waves at higher frequencies traveling more than 32 feet per second (10 m/s) >> faster than the low-frequency ones. >> That means that if you were standing on Mars, listening to distant music, you would hear higher-pitched sounds before you >> would hear the lower-pitched ones. >> >>paper: >> https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf >> >>So... >>Music from far away may sound funny? >> >>For Mars we will need compensation headphones with distance measurement and variable delays.... >>;-) >> >>Better use radio.. and earplugs/ headphones... >> >> >> > >Funny, I just delivered a lecture on transmission lines and noted that >microstrips have dispersion from the unbalanced dielectric constants >and skin effect. Rising edges get sloppy at the and of a long trace. > >I wonder if anyone has added surface-mount Heaviside loading coils to >a PCB trace. > >https://en.wikipedia.org/wiki/Loading_coil > >There used to be millions of 88 mH toroids on the surplus market, >telephone loading coils. > >The Mars thing is no big deal. You'd be dead too soon to worry about >acoustics. Imagine Burning Man (literally!) on Mars. It may matter for sonar based systems, distance measurements etc.. I have some small sonar based modules in use from ebay, something like these: https://www.ebay.nl/itm/185960647108