Voyager 1 Detects Plasma 'Hum' (phys.org) 56
A user shares a report from Phys.Org: Voyager 1 -- one of two sibling NASA spacecraft launched 44 years ago and now the most distant human-made object in space -- still works and zooms toward infinity. The craft has long since zipped past the edge of the solar system through the heliopause -- the solar system's border with interstellar space -- into the interstellar medium. Now, its instruments have detected the constant drone of interstellar gas (plasma waves), according to Cornell University-led research published in Nature Astronomy.
Examining data slowly sent back from more than 14 billion miles away, Stella Koch Ocker, a Cornell doctoral student in astronomy, has uncovered the emission. "It's very faint and monotone, because it is in a narrow frequency bandwidth," Ocker said. "We're detecting the faint, persistent hum of interstellar gas." This work allows scientists to understand how the interstellar medium interacts with the solar wind, Ocker said, and how the protective bubble of the solar system's heliosphere is shaped and modified by the interstellar environment.
Examining data slowly sent back from more than 14 billion miles away, Stella Koch Ocker, a Cornell doctoral student in astronomy, has uncovered the emission. "It's very faint and monotone, because it is in a narrow frequency bandwidth," Ocker said. "We're detecting the faint, persistent hum of interstellar gas." This work allows scientists to understand how the interstellar medium interacts with the solar wind, Ocker said, and how the protective bubble of the solar system's heliosphere is shaped and modified by the interstellar environment.
Space weather forecasts can now get better (Score:2)
This will help understand the impact of solar winds and what sort of noise that needs to be filtered.
A nice sunny day in the interstellar space!
Re:Space weather forecasts can now get better (Score:5, Informative)
This will help understand the impact of solar winds and what sort of noise that needs to be filtered.
No. These Voyager measurements are outside the heliopause, the place where the solar wind stops and the interstellar medium starts, so it doesn't tell us anything about space weather, which is the stuff inside the heliosphere.
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Interesting, thanks.
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This will help understand the impact of solar winds and what sort of noise that needs to be filtered.
No. These Voyager measurements are outside the heliopause, the place where the solar wind stops and the interstellar medium starts, so it doesn't tell us anything about space weather, which is the stuff inside the heliosphere.
Not sure, but perhaps the GP meant something more along the lines of why we can't detect the hum inside the heliosphere and what we can do so we can, etc... Either it's blocked at the heliopause, so faint that other noise inside steps on it, or perhaps something else just happens to cancel it out, etc... All that could help us understand more inside and out. Just guessing though.
Interesting. Quite important. Putting down monocle (Score:2)
Woulda/Coulda News For Nerds (Score:1, Interesting)
Can we get some more deetz here please? Any idea what's the source? Why does this tell us how the heliopause is shaped? Why is it monotone?
There are far more questions raised which aren't even attempted to be addressed in TFS and the paper is paywalled...
Possible mechanisms for the narrowband emission include thermally excited plasma oscillations and quasi-thermal noise
This is the best we get from the abstract. But they use the word, "turbulence" and yet the definition of this word uses "irregular", so how the fuck is describing it as "monotone" good. Is the usage here a buzz ward and/or has a different use in astro scien
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i'm nowhere nerdy enough but this seems pretty straightforward for me from the article:
monotone only means the pitch is doesn't change, not necessarily continuous sound. i guess it could be pulsing at irregular intervals.
about the shape of the heliosphere, it isn't a sharp static bubble either. measurement techniques seem to exploit knowledge of the source of perturbations like solar flares (no clue myself). that's no longer necessary since the probe can report about the hum continuously all by itself, reve
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Thanks, your explanation of monotone helped. I suspect more data is needed to detect any "pulsing", as such phenomena would be more constant with the sporadic effect of solar flares. The poster on this research seems to highlight better answers for my questions. Cheers.
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Is V11 moving in a straight line relative to the galactic gasses? If not, then absolutely there should be some variation unless the medium is so close to staionary that the probe's direction has no significant impact. Even if it is, a monotone seems to me to imply the gas is absolutely uniform in composition and velocity. That doesn't sound right.
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Your conclusions are what boggled me. I don't get how it could be uniform in this way. However, variance over galactic distance may take some time for the craft to detect. There doesn't seem to be any real statement about flow of galactic gases. The article and posters express the movement of these gas and aspects like cosmic rays more as an afterthought with different depictions. The two craft seem to be leaving in relative tangential paths to each other but are neither aligned or tangential to the "inters
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>Is V11 moving in a straight line
Umm, yes? *Everything* not under propulsion moves in a straight line, though since space is curved it doesn't necessarily look that way. E.g. it doesn't *look* like the moon is traveling in a straight line around the Earth, but that's what General Relativity tells us is actually happening.
>there should be some variation unless the medium is so close to staionary that the probe's direction has no significant impact
How do you figure? If you have uniform waves moving a
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An object remains in a state of uniform motion unless acted upon by a force. Propulsion is only one force. (And the Voyager probes have thermal emissions causing motion that hadn't been expected, so yes there is a very weak propulsion.)
Gravity is another. Impacts with radiation and dust, unless uniform, will alter direction. (Dust alters momentum, but also the centre of mass.)
Not sure what else vast quantities of highly charged dust will do that's significant here. But a moving charge can be quite interesti
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>Gravity is another.
Not according to General Relativity. Gravity is a manifestation of the shape of space. The most substantial force operating on the moon is the collision with the solar wind.
>Spacetime is curved not flat, so objects travelling in what they perceive as a straight line
There is no "perceiving", gravitational geodesics *are* straight lines through curved space. Just as a great circle is a straight line on the 2D surface of a sphere: a particle following that line will never change di
Re:Woulda/Coulda News For Nerds Here it is (Score:5, Informative)
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This seemed to be the most informative. Thanks a lot! Relative to this, it seems like they are suggesting another "wind" that may come from the galactic center but doesn't seem to be specifically reference in this way.
There is a lot being discussed in this poster. It seems they are describing the helisphere as having hemispheres with opposite flow, such much like the winds on the earth flow differently in north vs south. They also seem to be describing some kind of plasma interchange which I can only consid
Re:Woulda/Coulda News For Nerds (Score:5, Informative)
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Thanks. I skimmed it over. Sadly, I don't see any major conclusions. Most of it seems to refer to limitations in data and how to handle these challenges with detecting the signal. The poster on the research seems to be more enlightening. Check the other comment if interested.
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I suspect we'll have to wait a while for substantial conclusions - seems like they're mostly just publishing the observations for now so that the experts can start speculating on what's going on.
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Not entirely clear on your level of understanding, I apologize if I'm oversimplifying.
>Why does this tell us how the heliopause is shaped?
To be clear, I'm pretty sure they're talking about "the method by which it's shaped", not what the shape is.
And I imagine it's informative in the same way that being able to detect waves in the ocean tells us how coastlines get shaped. Essentially "these are the characteristics of the environment it's subjected to".
First result on DDG:
Quasi-thermal noise is caused by the thermally-induced motion of the ionized particles making up the plasma. The intensity and frequency spectrum of the quasi-thermal noise depends on plasma parameters such as the density and temperature, so those parameters can be deduced by measuring the quasi-thermal noise signal.
Basically, space is full of plasm
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Oops, sorry, ignore the slow moving river bit - that should be clear lake. Changed my metaphor partway through and missed a spot.
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Very interesting. Thanks for your insights and I enjoyed the way you visual try to explain these phenomena.
Howard Jones (Score:4, Interesting)
Maybe Howard Jones was right.
There was a time that there was nothing at all, nothing at all. Just a distant hum...
Re:Howard Jones (Score:4, Funny)
No, in the beginning there were the words. And the words were "And a one, and a two..."
Story brought a smile to my face (Score:5, Insightful)
Whenever I read a new story about the Voyagers, still chugging along and doing science, it lifts my spirits. We humans aren’t always governed by the lowest common denominator and the bottom line. We can occasionally accomplish amazing things.
Re:Story brought a smile to my face (Score:5, Insightful)
Re:Story brought a smile to my face (Score:5, Insightful)
My first thought when I saw this article: "Voyager 1 is still operational?!?!"
I am impressed and would love to see us dedicate so much effort into other projects.
The alignment that allowed the Voyager spacecraft to do their grand tour is something that happens once every couple of centuries. Even so, Voyagers were launched less than 20 years after we figured out how to orbit our planet. The circumstances that allowed us to hit this window were so unique and amazing.
Re:Story brought a smile to my face (Score:4)
Not much of it is working, but yes some parts still are. And, yes, that is amazing. If it had been given a larger nuclear battery, more of it might still be working, but it was never intended to be run for so long, the battery was way over-spec for what was needed and that's why it's still sable today. Sadly, AAA doesn't go out that far, so we can't really know what could be done.
It'll be interesting to see how long New Horizons lasts. If it's up to the same standards, we should get a lot more data about the extreme limits of the solar system.
How do they get Windows Update to work up there? (Score:2)
I cannot imagine any computer going more than a couple of years without an automated update. And then you need new disk drives to store all of the patch files. And it runs slower and slower. My computers only last a few years.
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They installed OpenBSD. The nuclear battery is a lie, they're powering it by Theo's force of will.
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Thanks for this perspective. Very refreshing :)
Nah, its just Gods fridge (Score:2)
Voyager has left the celestial front room and is just entering the kitchen.
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It will come back to our solar system 200 years later under the name V'ger. True story.
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V'ger? I hardly know her!
One more thing to do for the next mission (Score:5, Informative)
JHU APL is working on an interstellar mission [jhuapl.edu] design - a spacecraft designed to build on the Voyager legacy. It's intended to be much faster than the Voyagers, and optimized for exploring interstellar space rather than planetary flybys.
At one stage they considered using an Oberth-Kuiper maneuver to increase its speed, but the latest iteration seems to have dropped that option as it'd make the probe design difficult due to the close proximity to the Sun this maneuver requires.
Monotone ? hmm.. maybe it's just noise. (Score:2, Interesting)
Re:Monotone ? hmm.. maybe it's just noise. (Score:5, Insightful)
The Doppler effect applies when the source of the sound is a small area. This sound has a diffuse source.
Try driving through rain and see if the sound of the rain has a Doppler effect.
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Specifically, the Doppler effect applies when the speed of the sound source is changing relative to the observer. Stand directly in front of an approaching siren and there will be no Doppler shift (until impact...).
The Doppler effect occurs because as the siren (or whatever) draws near and begins to pass you, the portion of it's velocity that's in your direction (and thus affects the distance between sound peaks) changes. At a large distance it's moving almost straight towards/away from you (99.9...% of i
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I suppose I should say, the Doppler effect causes the perceived frequency to change when the relative velocity changes. You're always getting the Doppler effect when the source is moving towards/away from you at all, it'll just be a constant unchanging frequency shift, rather than the constantly changing "weeoouuuu" commonly associated with the effect.
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Voyager is moving at more or less constant speed relative to the distant source of the "hum" (whatever that is), so the Doppler factor is also constant. It's not, for example, approaching the source, then passing it and receding, which would cause an apparent down-shift in the frequency like one might experience when listening to a passing car.
Zappa said it best (Score:4, Informative)
I couldn't say where she's coming' from
But I just met a lady named Dinah-Moe Humm
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I couldn't say where she's coming' from But I just met a lady named Dinah-Moe Humm
Yep... You beat me to it.
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I come here for that.
A bit of confusion here. (Score:5, Funny)
What's actually happening is that after 40 years of flying through space, Voyager 1 doesn't have much too look at, so it got bored and started humming a very slow song. :)
Re:A bit of confusion here. (Score:5, Funny)
I hope you are correct. I'm betting that the hum is the resonate coming off the drives of the alien armada that is on its way to enslave us all.
I could be wrong.
Have you heard what's happening in outer space? (Score:3)
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*hands you a dozen milky way bars*
Interstellar Hum (Score:5, Funny)
Because the galaxy doesn't know the lyrics.
Thanks, I'll be here all week ...
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s/[Insert pithy quote here]/The universe consists of 5% protons, 5% neutrons, 5% electrons and 85% morons - Zappa/
The obvious... (Score:2)
So, hum a few bars, and I'll fake it....
Maybe we'll learn something about the Slow Zone.