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Mars Science

Perseverance Rover Reveals Speed of Sound On Mars (phys.org) 59

Posted by BeauHD from the sound-analysis dept.
An international team of researchers analyzing the sounds captured by the Perseverance rover has determined the speed of sound on Mars. Phys.org reports: Baptiste Chide, with Los Alamos National Laboratory, gave a presentation (PDF) at this year's 53rd Lunar and Planetary Science Conference outlining the findings by the team. [...] Chide reported that the team has used data from the microphone to measure the speed of sound on Mars. This was done by measuring the amount of time it took for sounds emanating from laser blasts from Perseverance to return to the rover's microphone. The laser blasts were used to vaporize nearby rocks to learn more about their composition. They found sound to be traveling on Mars at approximately 240 m/s. But they also found that different frequencies of sound travel at different speeds on Mars. The speed increases by approximately 10 m/s above 400 Hz. This finding suggests that communication would be extremely difficult on Mars with different parts of speech arriving to listeners at different times, making conversations sound garbled.

Chide says the microphone also allowed for measuring temperature on Mar's surface in and around the rover. This is because sound travels at different speeds depending on temperature. By measuring sound speed every time Perseverance fired its laser, the researchers were able to calculate rapid temperature changes. Chide also noted that the research team plans to continue monitoring and analyzing sounds from Mars over the course of a year to learn more about fluctuations during different events on the planet, such as during the winter months or when dust storms kick up.
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Perseverance Rover Reveals Speed of Sound On Mars More

Perseverance Rover Reveals Speed of Sound On Mars

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  • Non-sequitur (Score:4, Insightful)

    by wierd_w ( 1375923 ) on Thursday March 24, 2022 @03:11AM (#62385329)

    The local speed of sound in the open martian environment's effects on human language is a non-issue:

    1) humans attempting to breathe that atmosphere will be quite dead in very short order. Nobody is going to be trying to huff the frigid, dry, and highly sparse 90+% carbon dioxide of the martian atmosphere, unless they are supremely drunk, or pathologically stupid.

    2) Communication with a loudspeaker is a foolish prospect, as the loudspeaker would quickly get contaminated with the extremely powder-fine, and highly corrosive martian regalith.

    3) this just leaves radio based communication, which will have the human-facing sides of the exchange wholly within simulated earth atmosphere (vehicle, habitat, or suit environment-- does not matter.), which will have normal sound conduction properties.

    Why even bring this kind of thing up? It is a total non-sequitur.

    • Sound is more than just conversational (though this is what the article does delve into). It would be important to alert nearby people (even in a space suit, because those would probably transmit the sound into the suit from outside), about explosions or loud events. Even a PA system could conceivably be made loud enough to address all persons in space suits near by. All of this is to say nothing of the potential to geo-engineer Mars's atmosphere to be livable, though admittedly, that would change the compo

      • If humans are living on another planet and are still using a damn bullhorn to communicate with each other, then we probably deserve to die prematurely arguing about standard vs. metric bolts on the solar-powered electric moon-kart engine, which we still measure in horsepower.

        Nothing quite like the tradition of ignorance.

        • Gosh, such peremptory dismissal of a simple, low maintenance, and cheap communications system that has worked for hundreds of years.
          Sound has huge advantages over radio - it is localised, directional, and readily available. And, every human has a transmitter and receiver with acceptable bandwidth built in - and very reliable. I'd be surprised if it doesn't get used in some way on Mars.

          • "But they also found that different frequencies of sound travel at different speeds on Mars."

            TFS literally explained to you the exact challenges of using this "hundreds of years" old system that was designed around a certain planet's unique environment, and yet you sit here and challenge it.

            Thank you for explaining exactly why Ignorance will bring a bullhorn to another planet and try and use it, in the sheer face of science.

            Thank you for explaining exactly why we'll continue the Darwin Awards for many generations to come, because none of us, are as dumb as all of us.

            • The concerns were addressed in the thread, dumbass. Go Darwin-award yourself, your comments add no value to the conversation.
            • You expected someone to have read TFS, let alone TFA (or even any paper that actually covers the ground of this presentation) before commenting.

              You must be new here.

              I wonder who got UID 10,000, or 100,000?

      • Re: (Score:2)

        by noodler ( 724788 )

        (even in a space suit, because those would probably transmit the sound into the suit from outside)

        Not very likely. Due to the low pressure in the atmosphere the kinetic energy contained in the sound wave is going to be low. A space suit on the other hand has a lot of mass. The vibrations the atmosphere will be able to induce in the space suit and in the air contained in the space suit is going to be comical and you won't hear a lot, or actually, you won't even hear a little.
        Communicating by sending sound through the atmosphere is going to be quite quite bad even without this new finding.

        Even a PA system could conceivably be made loud enough to address all persons in space suits near by.

        Could it? How lo

        • Re: (Score:2)

          by tragedy ( 27079 )

          No geoengineering is going to increase the mass of mars to a significant degree. That means that the atmosphere, whatever the composition, is going to stay quite rare.

          Not that it's simple to do, but if you were actually geo-engineering/terraforming to such a degree, you could actually build a bubble around the entire planet to contain the atmosphere inside a physical barrier. Completely sealed, or with only a few holes, it would hold itself up, but it could also be supported with gasbags on the atmosphere side. The idea seems preposterous, but only when considered alone. In the context of terraforming a whole planet, it actually sounds quite reasonable. So the concern ab

          • Re: (Score:2)

            by noodler ( 724788 )

            Eventually humanity might become advanced enough to undertake such projects, but it won't be anytime soon. And ultimately i don't get the point of colonizing these inhospitable places. We can't even keep earth balanced, so it speaks to our arrogance that we think we can terraform another planet without severely fucking up in one way or other. Another obvious flaw with this line of thinking is that it requires something close to total harmony between all people on earth. Otherwise there can't be a unified pl

            • Re: (Score:2)

              by tragedy ( 27079 )

              Eventually humanity might become advanced enough to undertake such projects, but it won't be anytime soon. And ultimately i don't get the point of colonizing these inhospitable places. We can't even keep earth balanced, so it speaks to our arrogance that we think we can terraform another planet without severely fucking up in one way or other. Another obvious flaw with this line of thinking is that it requires something close to total harmony between all people on earth. Otherwise there can't be a unified plan for the future of mars. US, China, India, EU and possibly even Russia will all act in their own self interests and will frequently collide on social, political, moral, financial, etc. etc. issues and many wars will follow.

              As I said though, this is in the context where we actually are doing geo-engineering/terraforming. It's if P, then Q and I made an argument for Q, but here you're arguing against P. For the most part, you're making reasonable arguments. I will say that the problem with "what's the point" arguments is that you can make them for just about every big project humans have ever taken. The world is covered with artefacts of human history where we have undertaken huge projects of one kind or another and you can eas

              • Re: (Score:2)

                by noodler ( 724788 )

                Well, once again "the foreseeable future" doesn't really apply here. This is a purely speculative future.

                I understand. I just don't think it's a very realistic one. Basically i think that by the time we can do it we won't need to do it anymore.

                Soooo, they first appeared when Musk started SpaceX? Rather than say: existing since before the first manned spaceflight occurred? Consider _Red Planet_ by Heinlein, or _The Martian Chronicles_ by Bradbury.

                So your reference for the future of humanity is a 1948 sci fi novel that features martian aliens? Great...
                Anyway, i'm referring to the recent sentiments that colonizing and terraforming mars is reasonable in a relatively short time frame. I think there is little reason to colonize mars on a large scale, much less terraform it, even more so building atmospheric shielding.

                • Re: (Score:2)

                  by tragedy ( 27079 )

                  So your reference for the future of humanity is a 1948 sci fi novel that features martian aliens? Great...

                  Technically I mentioned _two_ pre-space age sci-fi novels by well known science fiction authors. Many sci-fi stories of the time (and the present) feature exciting speculative elements like that. Same as seafaring adventure would be likely to include pirates. It is at least a lot less offensive than most of the Westerns featuring marauding "Injuns", etc. The example was simply meant to illustrate that ideas about colonizing other planets were around well before private space companies or, in fact, human spa

          • you could actually build a bubble around the entire planet to contain the atmosphere inside a physical barrier.

            You'd have to put it on stilts. Even if you inflated it to the 100kPa of Earth's sea level atmosphere, attempting to support it buoyantly (with Helium, from the Great Terraforming Magic Materials Top Hat) you'd still find that any instability would accelerate, forcing the higher parts higher, and the lower parts lower. "Crunch, Grind Splat".

            I assume that you get the magic materials fro this disa

            • Mars soil is at least 40% oxygen. I don't know the chemistry involved to extract it, I assume a lot of energy and some catalysts are involved.
              • So is Earth's. So what? The metals and semi-metals that combine with oxygen to form the oxides and silicates that make up the outer 2/3 of the planet all react, relatively readily, with oxygen for form those oxides. So, if you used some process to separate the oxygen from the oxides and silicates (difficult - there is a reason that mineralogical and geochemical data is normally presented as percentages of metal/ semi-metal oxides - but doable, if you've got the energy available) that would be great, but you

    • Point #2 is false, for one thing. You don't think loudspeakers can be made that can resist corrosion in Mars conditions?

    • No, of course humans wouldn't be able to breathe the air. But that doesn't mean communication through sound is useless. Speakers can be sealed against the elements. One advantage of communication via sound is that no special receivers are required. No, we won't have two people standing out on the Martian desert having a conversation without spacesuits. But there are many other ways sound could be utilized for communication, such as audible alarms.

      • Re: (Score:2)

        by tragedy ( 27079 )

        Sound through a super-thin atmosphere and then through spacesuits seems like it would be pretty greatly reduced. It seems like you would be better off putting those speakers into the ground and putting microphones in the boots of the spacesuit (and compensating somehow for the sounds generated by walking around). Otherwise, it really seems like radio waves would work a lot better. Longer range, better penetration through various objects, etc. There is no reason to think that radio waves would be any less di

        • Sound through a super-thin atmosphere and then through spacesuits seems like it would be pretty greatly reduced.

          I have a feeling that, with an approximately spherical suit helmet, and a plane(-ish) wave of sound impinging on it, most of what little energy couples to the helmet is going to go to vibrating the whole helmet to and fro, rather than producing a new sound wave inside the helmet. When I've had to use a positively ventilated helmet and face mask at work, I would also get issued with a radio coupl

    • Maybe a dumb question, but does this shed any new light on SETI's sending/receiving radio signals? If sound travels at different speeds on other planets is sending or hoping to receive radio communication even more futile than we already assumed? Or is that just not how the array works in the first place?
      • Nobody in SETI is anticipating that any sort of voice communication would be received. Data would e transmitted and received ; you'd need to design your signals very carefully to include enough information for the recipient to recognise your coding scheme, then your signal scheme (maths, then some sort of language, in the computer sense).

        Or is that just not how the array works in the first place?

        Sorry, you've lost me there.

    • It's also quite false. The difference in the speed of sound for different frequencies isn't different enough to cause separation at the small range of frequencies that people speak at, and wouldn't be even be perceptible at distances people are capable of hearing each other at. In short, it's a inaccurate non-sequitur. The kind of garbage people come up with to draw attention to otherwise uninteresting papers.

    • Re: (Score:1)

      by yagmot ( 7519124 )

      Wow! You must be real popular at parties and with your friends. When someone brings up the superpower question (flight or invisibility) do you shoot that down because it's a fruitless exercise? Do you also shake your fist with rage and yell at the screen when you watch sci-fi movies or TV shows?

      Look, we all know it would be impossible for humans to have a conversation out in open air on Mars, but stuff like this is fun to think about. And if you're going to use a big boy word like non-sequitur, at least lea

  • Obviously this was a worthy experiment, but I would assume we guessed this would be the case in advance right? I mean from simulations and experiments carried out on Earth in partial vacuums with a Mars like atmosphere.

  • The standard bandwidth for old phones was 400 - 4 kHz, so the actual 'problem' here is virtually non existent. Interesting anyway.

    • The problem is non-existent because people won't stand around in the martian atmosphere (or mostly, comparative lack thereof) and try to talk to one another. But if they were, it would be a real problem for speakers of tonal languages.

    • You are talking g711, roughly 300 - 3400hz. which is still the standard on the PSTN. The problem with g711 is that most consonant sounds fall outside this range, leaving mostly vowel sounds. Out brain uses context clues to fill in the blanks. The letters F and S sound identical when sampling is limited to this range. If I were to say "My daughter is failing in college" you would require more context do determine if she is on academic probation or if she joined a yachting team. This phenomenon is
      • The telephone system was engineered to accommodate the electronics and cables of the era. The human speech system was not engineered, at all.

        The human speech system needs to be re-designed to be compatible with the communications technology.

        This may seem heretical to you. We've been doing it in the oil industry for decades. Since the introduction of helium-oxygen gas mixes in the early 1960s, the problem of "squeaky voice" being incomprehensible to the surface has been dealt with by frequency-shifting amp

  • It's the same thing on Earth. (Score:4, Interesting)

    by Pig Hogger ( 10379 ) <pig@hogger.gmail@com> on Thursday March 24, 2022 @07:41AM (#62385667) Journal
    This is why yodeling has been developed by the Swiss, as the frequency shifts are a better method of modulation than the multifrequency spectrum of everyday speech.

    Also, other alpine people have developed a form of whistling to communicate like yodelers do.

  • Mars: 240 m/s
    Earth: 340.29 m/s

    Mars: 536.8647 MPH
    Earth: 761.2071 MPH

    Mars: 864 kph
    Earth: 1225.044 kph

  • > At 20 C (68 F), the speed of sound in air is about 343 metres per second (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn)

    https://en.wikipedia.org/wiki/... [wikipedia.org]

  • The possessive for Mars isn't Mar's, you illiterate dolt. This writer gets paid good money to write about physics and can't get simple possessives right? Must be a miserable existence to be so shitty at your job. Not to mention the /. "editors" leaving it in there, but that's just par for the course for them.

  • So only a problem for children, then? Adult speech doesn't generally modulate that high.

    Shouldn't be too much of an issue, IMO. By the time we have children on Mars, I expect there will probably be a permanent martian colony either under a dome or underground, with a sustained breathable atmosphere where sound would travel normally. There probably won't be too much call for children to be out and about on the open surface of Mars.

    • I expect there will probably be a permanent martian colony either under a dome or underground, with a sustained breathable atmosphere where sound would travel normally.

      I can't see any situation where anybody would talking to each other without either being in a pressurized environment (which wouldn't have significant differentials), or in a space suit, in which case radio would be used instead of direct air-to-air communication because such would be muffled by helmets anyhow.

      • Re: (Score:2)

        by mark-t ( 151149 )
        You raise a good point about helmets muffling people's voices. Although I suppose you could use helmet-mounted external speakers to transmit your voice in the air, much like what some people have today in their motorcycle helmets. With radio, it just seems to me like there's just more things that can go wrong and fail.

        • Re: (Score:1)

          by Tablizer ( 95088 )

          Maybe a speaker helmet can compensate for the frequency shifts? (Given an estimate of listener distance.)

          • Re: (Score:2)

            by mark-t ( 151149 )

            As I said, that wouldn't necessarily be a problem for ordinary adult human speech, which generally does not even modulate as high as 250hz, let alone 400hz.

            Only children's speech modulates any higher than 300hz, and they might experience problems if the effects become pronounced at those frequencies. However, as I said, I can't see too much of a call for children to *ever* be out and about on the open surface of mars.

            • Re: (Score:1)

              by Tablizer ( 95088 )

              Bernadette from Big Bang?

              "S" and "T" sounds tend to require higher frequencies to be clear even in adults.

      • The interior of a space suit is a pressurized environment.

        It is also heated to a higher temperature than the exterior environment on Mars (unless someone drills a hole some 10km deep, and then lowers you into it), and has a slightly lower radiation dose rate (unless you've got Homer Simpson's "hot rod" in your pocket).

  • Everybody knows that martians used telepathy to communicate. Weâ(TM)ve know this since the early sci-fi movies. Sheesh.

  • Bye clant breevee!!!

  • I am in awe of the amount of intelligence present to do work like this and the things that these folks can figure out. Bravo!

  • When running this quad around?

  • Actually I have no idea. Interesting article, if you want to name more sound effects for your work visit prosoundeffects.com [prosoundeffects.com], very informative, I really enjoyed it.

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