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What does another world sound like? - New video from Nasa on Mars
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Graeme wrote: "REF: Youtube: https://www.youtube.com/watch?v=ZK5bO...Sound on Mars."
Marvellous, isn't it?
A billion dollars to listen to wind! Hint - come to Wellington and hear it for much less, no need to speed up the frequency and not only that, get blown about while you are at it :-)
Ian wrote: "A billion dollars to listen to wind! Hint - come to Wellington and hear it for much less, no need to speed up the frequency and not only that, get blown about while you are at it :-)"That's self-promotion -:)
Actually, more like self-demotion :-). There is nothing terribly attractive of winds that cause trees to grow with a bend towards the east!
Come on, Ian. You know it's cool to hear Mars winds. Sounds from outer space!!
Yes, but the curious thing is, what is it we are listening to? How much of what we are hearing is due to the rover itself? For example, if you blow air over a glass, you hear a resonance, that changes its pitch as you add water. Are we listening to something that depends on the shape of what we sent there?
Ian wrote: "A billion dollars to listen to wind! Hint - come to Wellington and hear it for much less, no need to speed up the frequency and not only that, get blown about while you are at it :-)"Maybe you should read up on the actual mission before making such judgements, Ian. It's purpose is to study the interior of Mars to determine the extent of its geological activity and shed light on its formation and evolution - which will also teach us about Earth's own formation and evolution.
The recording of Martian wind was nothing more than a lucky coincidence. And the sounds we were hearing were recorded by two separate sensors, an air pressure sensor and the seismometer. To assume the mission controllers didn't even know what it was is awful presumptuous. Last, but not least, the InSight mission is a lander, not a rover.
Matthew, of course I know what the mission was, and of course the wind caused the noise, but how? The two sensors is irrelevant because vibrations go across everything that is connected. What you are hearing is a vibration that has been converted into an electrical oscillation, so what is vibrating? Low pressure air is vibrating why? The usual reason for noise from wind is the wind interacting with something, or with itself in circular motion, like a tornado. So, what gives that low frequency vibration? Matthew, please enlighten us all.
Ian wrote: "Matthew, of course I know what the mission was, and of course the wind caused the noise, but how? The two sensors is irrelevant because vibrations go across everything that is connected. What you a..."Like I said, the recording was picked up by two seperate sensors. These include the Auxiliary Payload Sensor Subsystem (APSS), which records vibrations in the air, and the Seismic Experiment for Interior Structure (SEIS), which is designed to sense vibrations in the ground, but was able to pick up oscillations caused by Mars' wind because it hasn't been deployed to the surface yet.
So no, the sensors are not irrelevant, they picked up the sounds of the wind because measuring vibrations is exactly what they are designed for. Here's the press release and a rundown of the InSight's instruments, if you're interested:
https://www.nasa.gov/press-release/na...
https://mars.nasa.gov/insight/spacecr...
From the NASA statement (Matthew's first link) : The seismometer recorded lander vibrations caused by the wind moving over the spacecraft's solar panels, which are each 7 feet (2.2 meters) in diameter and stick out from the sides of the lander like a giant pair of ears. That is more or less what I said - the wind was making something vibrate.
The APSS is different - it measures air pressure so the air pressure must be oscillating, presumably due to turbulence caused by the obstructions. The turbulence can cause pressure oscillations as pressure waves generated by obstructions reflect and interfere. (I am assuming the oscillations are not in the detector, because I have no idea what its specific design is.)
Air does not make sound, but it transmits sound from something vibrating. Sound is, of course, a pressure oscillation, and while the wind is causing the vibrations, it is either something due to the lander vibrating, or, and we don't want to go down this path, something else vibrating. An example of what is a pressure induced oscillation is the organ pipe, and what yogurt depends very much on design.
Ian wrote: "From the NASA statement (Matthew's first link) : The seismometer recorded lander vibrations caused by the wind moving over the spacecraft's solar panels, which are each 7 feet (2.2 meters) in diame..."You're concerns notwithstanding, I think it might be a bit presumptuous to think that the mission controllers weren't able to differentiate between oscillations in the sensors and vibrations from the lander itself. But who cares? The bottom line is, that noise is being created by the Martian wind. So the claim that this is what it sounds like to be on Mars is entirely correct.
This is the first of many discoveries the lander is likely to send back, so the cynicism and the questions seem unwarranted to me.
As to what discoveries it will make, my guess is, not many, mainly because this is a data gathering exercise. For example, it will measure the heat loss from the interior. Everyone knows there is one, so it doesn't really qualify as a discovery, but we do not know how big the heat flow is. My guess is the Marsquakes will be a bit like Moonquakes, but not as pronounced. Anyone else care to guess before we know?
The lander is a data gathering exercise? What exactly do you mean by that and how will that limit its discoveries? Also, measuring the rate of heat loss from the interior is merely the tip of the iceberg. The temperature and seismic data it is built to gather is likely to tell us a lot about Mars' interior structure - including the size of its core, whether or not it is liquid, and the size, thickness and composition of the mantle and crust.
This information will help us to understand why Mars' lost its magnetic field, when geological activity ceased, the extent of its seismic activity today, and how it formed over 4.6 billion years ago - which will tell us a lot about the formation of other terrestrial planets (like our own).
However, I think you may be right about Marsquakes, it does stand to reason that they would be milder since it doesn't have a larger body interacting with it.
Graeme wrote: "Thanks Matt, great links."No problem. Ian's questions aside, I'm glad people are fascinated by this. It really is a historic first.
Matthew, the heat flow will tell us exactly that - what is the heat flow there. The location is important, because Elysium was an active volcanic region, and the volcanic region may have even erupted within the last few million years (if interested, see Vaucher, J. and 5 others. 2009. The volcanic history of central Elysium Planitia: implications for martian magmatism. Icarus 204: 418-442.) We know Mars is rocky, so it will have its share of uranium, thorium, so we can estimate how much residual heat is there and being generated. The exact amount is unknown, but because Elysium Planitia is hardly representative, the measurement of crustal thickness there, while interesting, will only tell us about there.It won't tell us when geological activity ceased, any more than the studies on volcanism, but it will firm up some data, which is important. We think we know why the magnetic field went - the core is seriously short of iron, and the basic rocks have a big excess of iron oxide compared with Earth - the reason being, at least in my opinion, the iron did not melt and go to the core, but instead oxidised, either in the planet or maybe even in space before Mars accreted. I also doubt it will tell us more than we know now about how it formed, but I guess we shall have to wait and see.
As an aside, there is nothing wrong with data gathering - it is extremely valuable. The Moonquakes, by the way, have nothing to do with Earth - they are thermal due to the two weeks roasting, followed by two weeks really freezing. Marsquakes would likely be due to the contraction of the stagnant lid as the interior cools. Mars has no possibility of ever having had plate tectonics because the higher level of iron oxide in the silicates do not densify enough when cooled, so the possibility of pull subduction is no longer available, and of course it is these tectonics that is responsible by and large for Earthquakes.
If it's that windy, don't forget your snowboard gear and headphones when packing for Mars-:)
Unlike what you read in "The Martian", the wind, while fast, is not very dangerous. Because of the low pressure, a 200 k wind would give the force on you like a summer breeze.
Yeah, but I wouldn't want all the dust kicked up to get into my eyes. :)
J.J., if the dust can get in your eyes you have another problem: you forgot to put on your helmet (or you put it soon incorrectly and there is a leak :-( However, you are right in that the dust would be a real nuisance. In one of my novels, the settlers start off by getting water by squeezing to from the atmosphere, which requires a lot of pumping and filtering of air - a dust storm gave real problems.
Ian wrote: "Matthew, the heat flow will tell us exactly that - what is the heat flow there. The location is important, because Elysium was an active volcanic region, and the volcanic region may have even erupt..."Measuring the heat flow won't, but that's what the seismometer is for. Hence why I mentioned seismic data in my last post. It will be measuring the sound waves caused by marsquakes and impacts to learn more about Mars' interior. And what you offer there is merely one a few theories, the most widely-accepted being that Mars' lower mass meant that its interior cooled more rapidly.
Whereas its inner core was not under enough pressure to solidify, it remained liquid and was also not hot enough to keep the outer core in a liquid state. This arrested any dynamo effect that would have powered Mars' magnetic field, as is believed to be the case with Earth. Gathering seismic and temperature data will help resolve this mystery, which I already said.
Also, yes they do. The moonquakes you are referring to are of the thermal variety which affect only the upper mantle. Deep moonquakes, however, are believed to be the result of tidal forces - i.e. its gravitational interaction with Earth. Impact quakes are self-explanatory, while shallow moonquakes are believed to be the result of ongoing tectonic activity caused by impact basins.
https://www.sciencedirect.com/science...
http://adsbit.harvard.edu//full/1980L...
As for Mars and plate tectonics, there is certainly no indication of it having any in recent history, but there is evidence of tectonic activity in its distant past. These include the differences in elevation between the northern plains, and southern highlands and the Tharsis Bulge. These three regions, btw, are considered distinct physiographic sections based of their different geological and tectonic characteristics.
Matthew, I wrote, and you quoted, "the heat flow will tell us exactly that - what is the heat flow there." When you say it won't, I am sorry but that is obscure. Mars' size is relevant, but with the thorium and uranium it must have accreted, lack of heat cannot be the reason there is no magnetic field, at least from an extremely early stage. The reason for an absence of a magnetic field is likely to be the absence of iron in the core, which when it melts remains liquid. The reason there is an absence of an iron core is reasonably obvious, but not if you accept the magma ocean concept. The Tharsis bulge is almost certainly a consequence of the shock wave from the Hellas impactor - they are very close to being opposite. Similarly, irrespective of what you think, the scientific literature indicates that the Elysium volcanic field erupted reasonably recently, so there must be magma underneath. The modelling I have seen suggests the crust is about 60 km thick, which is certainly thicker than Earth's.The difference in altitude between the northern plains and the southern highlands is unknown, but as I pointed out, Earth has something similar in that the continents are mainly in the north. On earth this is simply a matter of density. The southern highlands are not felsic (as far as we know) but basaltic rocks can have real density differences and we don't have any sample analysis from the southern highlands. I agree we don't know enough. There has never been plate tectonics there, but there has been tectonic activity - depending on how you define tectonics. The volcanic uplift could be included as tectonic activity, and there has bene plenty of that.
Finally, for everyone, a confession - for the first time we have a mission that will dig down five meters and what do we see? No attempt to analyse the composition at depth. There are several reasons why this could be important. For example, the area was once a lake-bed (I believe - I am not certain where it is in precise detail and I don't know what volcanic changes have occurred) and all logic says water could not have flowed without something to lower its melting point. That something could be down there, but we won't know. That annoys me, since I have predicted what I think it was.
J.J. wrote: "Yeah, but I wouldn't want all the dust kicked up to get into my eyes. :)"Well, in the movie "The Martian," dusty storms were a real issue. Kinda makes you wonder how Hollywood worked out that air pressure on Mars must increase during a storm to make it that dangerous....
(:-) ...)
Graeme, since when does Hollywood put truth ahead of what they need for their story, or what they think their audience wants?
Of course, you can't hear wind, but didn't I hear some vibration caused by the wind on Mars? And wasn't that cool?
Yes, Scout, you definitely heard a recording of some wind-caused vibration. Cool is a matter of opinion, but since Mars can get down to minus 120 degrees C, although hardly likely there and then, definitely cool, if not outright cold, especially at night.
Ian wrote: "Matthew, I wrote, and you quoted, "the heat flow will tell us exactly that - what is the heat flow there." When you say it won't, I am sorry but that is obscure. Mars' size is relevant, but with th..."How is that obscure? The Heat Flow Probe won't tell us when Mars' geological activity ended, I agreed and said that's what the seismometer is for.
//The reason there is an absence of an iron core is reasonably obvious, but not if you accept the magma ocean concept.//
What absence of iron? Current interior models of Mars indicate that it is composed of an iron-nickel alloy, just like Earths (albeit with more sulfur, which is what would have allowed the outer core to harden). Also, the field disappeared 4.2 billion years ago, which coincides with when the newly-formed planet would have cooled off. Mars' lower mass and interior cooling is a much more straightforward explanation.
https://hal.archives-ouvertes.fr/hal-...
https://www.newscientist.com/article/...
//The Tharsis bulge is almost certainly a consequence of the shock wave from the Hellas impactor.//
I thought so too, once. However, that theory has been largely overruled by research that suggests that Tharsis was largely in place 3.7 billion years ago, whereas the Hellas Basin was created in an impact that happened between 4.1 to 3.8 billion years ago.
//Similarly, irrespective of what you think, the scientific literature indicates that the Elysium volcanic field erupted reasonably recently, so there must be magma underneath.//
Uh, it's not about what I think. It's about what recent scientific literature says, which I know about because I write about this stuff for a living. And that literature suggests that the Elysium volcanic field has retained a youthful look because it is located in the northern lowlands, where a liquid water ocean would have weathered it.
That's much more likely than the possibility that the Elysium region being recently formed. There's also the nakhlite meteorites, which were formed 1.3 billion years ago, that suggest that volcanic had slowed significantly in that region at the time.
//There has never been plate tectonics there, but there has been tectonic activity - depending on how you define tectonics. //
Is that a fact or an opinion? Because it's actually one of the three most-widely accepted theories that internally-driven plate tectonics are responsible for the north-south dichotomy, and that this occurred during Mars' earliest epochs. But like I said, its one of three and there's simply not enough known to say for certain.
http://adsabs.harvard.edu/abs/2006JGR...
I feel like you're trying to move the goalposts here and (no offense) it sounds like your injecting your own theories into the mix and relying on older studies at the expense of more current ones.
Matthew, some quick responses.The absence of iron in he Martian core - the relative density of Mars is roughly 3.8, as opposed to Earth, Venus and Mercury each being > 5.3. Basalt typically has a relative density of 3 - 3.8, so the odds are that Mrs is very mainly basalt, especially since apart from some relatively thin deposits of plagioclase on the darker zones, Mars has essentially no felsic rock (density 2.5 - 3) On the other hand, the amount of iron oxide in the basalt is significantly higher than Earth, which is why Mars CANNOT have plate tectonics - the density of the basalt does not increase enough when cold to operate pull subduction, thanks to this iron oxide content. Mars got its share of iron, but not in the metallic form.
Hellas was formed 4.1 - 3.8 Gy BP, Tharsis 3.7. (Your figures) How does that show Hellas could not have been the cause of Tharsis? Causality requires cause precedes effect, and it did. The shock waves of the impactor are almost instantaneous in travelling, but the silicates have a strong resistance to movement so some delay in getting started is expected.
As for Elysium, I have seen a few scientific papers arguing for the the "recent" eruptions. I was merely citing them - I can find references if it is important. It has nothing to do with me.
The absence of plate tectonics is because of the rock composition issue noted above. I have no idea exactly why the north is lower, but there are various theories. I do go on the density arguments, though. There can be no pull if the rock refuses to go down.
As for the date of the information, I hope i am reasonably up to date, but the age is irrelevant - if it is old and true, it remains true.
Sound on Mars.