Re: OT: sound speed depends on frequency on mars

On 31/08/2024 12:34 am, john larkin wrote:

On Fri, 30 Aug 2024 11:13:05 GMT, Jan Panteltje <alien@comet.invalid>
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 hope you pointed out that buried strip-line isn't dispersive. I have pointed this out here from time to time.
https://www.wevolver.com/article/stripline-vs-microstrip

I wonder if anyone has added surface-mount Heaviside loading coils to
a PCB trace.
 https://en.wikipedia.org/wiki/Loading_coil

It would be a bit silly. You can make lumped constant transmission lines by linking a series of capacitors with discrete inductors, if you want a high impedance transmission line - people sold them thick film hybrid assemblies, and I even used a few, a very long time ago.

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.

Unless you wore a pressure suit. Not exactly the usual music festival costume, but you'd need to wear one to survive an outdoor concert on Mars.
--
Bill Sloman,