The neat thing about the radio tech in question here is that while the signal continues to weaken, broadcast and reception tech keeps up with it. I don't know when (if) the curve runs out on that process, but we have a planet's worth of resources to bring to bear on the problem, as long as someone's willing to keep paying to upgrade the transceivers (and it's work that pays some nice side dividends in terms of being a convenient toy problem for testing new radio tech).
Since we know exactly what we're looking for and exactly where it should be, we have all kinds of neat radio tools to bring to bear on sampling a faint signal from interstellar noise.
What about sending a repeater station once in a while to follow them? Or would it be inefficient compared to constantly updating radio tech here on Earth?
Received radio power decreases as the square of the distance. If the repeater started now, to be useful it would have to be similarly large to the big radio telescopes used to receive the signal. It would need to have the same speed as the probe it was following to keep up the signal. But the Voyagers each were massively accelerated by their giant planet encounters. Launching a much-more-massive repeater at much higher initial velocity than the original probes is nonsensical.
The point is it would be massive relative to the probes, and it would also have to be moving faster than them to be useful anytime soon. And if you could launch something that massive going that fast, why bother making it a repeater. Just launch a new probe with a bigger antenna.
Right, I am not sure the limiting factor here is our ability to send or interpret the received signals. I think the limiting factor that is most impactful is the probe itself.
Eventually, its power source will die out, its components will fail, or enough cosmic rays or debris will corrupt enough of its systems it can no longer transmit.
Given those factors, I do wonder what the expected lifetime of the probe is, with the power source being the most clear "game over" line.
It appears that both Voyagers are slated to have some experiments disabled soon (2020 and 2021) to best use remaining power from the RTGs, but since the RTGs are nuclear sources, the decay rate is independent of power draw (it's more an issue of switching off the experiments to avoid peak draw killing the ship).
Voy1's expected to lose too much wattage to turn on the radio by 2025; I can't find a quick number for Voy2.
EDIT: It appears Voy2's power package was expected to allow mission operation through 2020, so sayeth Wikipedia; no idea if that implies the radio was expected to die this year or this was the year the craft would need to be reconfigured for a scaled-back mission profile to maintain enough power for attitude control and radio transmission.
IIRC the main limitation is the power supplies. They're failing slowly and they need to keep turning off instruments to allow it to keep running.
I believe it's expected that they'll need to pretty much turn off all of the instruments in the next 5 years, and after that it can run it's comms a bit longer but nothing else.
Edit: found an FAQ page from JPL about the Voyagers:
It looks like this year they need to start shutting down instruments more aggressively, expect to be able to run at least once instrument until 2025, and then there's a possibility of the voyagers staying contactable until 2036 with no instruments running.
I was just wondering why they would want to have a probe that can still run its comms equipment but can't return anything of scientific interest anymore because its instruments are no longer working... but then I realized that a nuclear power source is not like an ordinary battery - you can't use up more power now (e.g. to run the scientific instruments longer) and have less available later, you have a steadily declining "power budget" which would simply be wasted if not used?
Not just testing but I'm sure a "known" signal coming from outside the solar system would be invaluable for developing and tuning deep space network systems.
Correct. The ability to determine distance and velocity allows the trajectory and dynamics of the instrument to be computed with high precision.
To see one application of this information, look for discussions of the "Pioneer Anomaly". That particular effect is now understood, but had it held up to detailed systematic-effect analysis, it would have affected our understanding of gravitation on solar-system scales.
When one enters entirely new territory, the understanding derived from single reliable measurements can be quite substantial.
The bigger problem is that they're powered by an RTG, which will soon cease to produce enough power to run the probes. They expect to start shutting down some of the few instruments still running next year, no longer have any power available for science around 2025, and run out of enough power to do radio transmission around 2030.
If the probes still had enough power by then, the current DSN would be able to receive data until the mid-2030's.
Digital formats, error correcting codes, wide band (to avoid narrow occlusion from stopping us from recieving), redundancy of transmissions, long bit frames that allow us to average our readings (at the cost of bitrate, akin to long exposure photography)
This link helped me understand it better. Basically they introduce an extremely redundant orthogonal code and since noise is somewhat random if your code is long enough you can reconstruct the signal despite the noise.
Noise is spread out over frequency, you see under the noise floor by using signal-locked narrow filtering that rejects almost everything except the signal in question. All of the target signal is admitted by your filter, but only a tiny amount of the noise is, so your signal is no longer under the noise.
If that isn't much, run slower and coherently combine more data. White noise power with averaging will fall with the reciprocal square root, while your coherent signal power will add linearly-- eventually you overcome the noise assuming your transmitter/receiver oscillators are locked well enough to sum coherently.
If the noise is not white, e.g. if there are tones in it-- these steps work less well.
Now consider how direct sequence spread spectrum works:
I take a slow signal-- like a 50 bit per second 100Hz wide BPSK signal-- and spread it out by xoring it with a fast random sequence (say a 1MHz random sequences).
The result looks like noise. But if you xor it again you get the original signal back.
When you transmit it, the receiver gets a sum of your signal and noise sources. We can analyize each separately: If you xor white noise with your random sequence -- nothing much happens: you end up with white noise with the same power. So when the receiver xors the received signal with the random sequence, as mentioned nothing much happens to white noise. But any tonal noise gets converted into white noise (because it is independent of the random sequence), and your transmitted signal is recovered and ready for reception using a narrow locked filter.
Modern digital communication almost always uses error correcting codes which allow perfect reception even when some bits are corrupted (early space probes were among the first applications of powerful error correcting codes).
Low noise 8 GHz band, Reed–Solomon coding,huge directed antennas (almost 4 m in Voyager, over 30 meters on the Earth), tens of watts from Voyager, thousands watts to Voyager.
I hope one day soon we can use a SpaceX Starship super heavy to accelerate a probe at much higher velocities. The only thing is, unlike rockets, there is little incentive for private companies to invest in producing better, cheaper space probes.
It's unlikely to happen. Using the numbers from Wikipedia for Starship, for a 5 ton payload the first stage has a delta-v of 3.8km/s and the second stage of 8.8km/s. That gives only 12.6km/s in total, while Voyager had around 20km/s after its departure from Earth. Even if the Starship is fully refueled in orbit to give it another boost (and we don't want to recover it), we get only 21.4km/s. However, the Voyagers got a gravity assist from all the outer planets, where they gained even more speed. That's only possible if they are all aligned, which happens only once every 175 years. That's also the reason why New Horizons, the Pluto probe launched 30 years later, will never overtake the Voyagers: it's travelling slower because it didn't get to do the gravity assists (even though it was launched at a higher speed from Earth).
Also it's important to note that Starship isn't really optimized for such missions due to its high dry mass. It's made to bring a lot of mass to orbit cheaply, not really to accelerate it very fast.
I don't think you use starship as the stage that pushes the probe to escape velocity, you use a ion engine (which spacex also develops for starlink). They're an order of magnitude more efficient... Starship just lifts it to orbit.
The problem with ion engines is that they need quite a lot of power, which becomes problematic in deep space. Solar panels aren't really viable outside the orbit of Mars.
Anyway, yes, of course there are countless variations that can be done to make it work. Sticking a Centaur or two in a Starship also seems to be viable. But the parent comment specifically asked about Super Heavy/Starship here.
Ion engines need a lot of power, but scale down quite well to lower powers and lower thrust. And even with an ion engine, you'd only be running it for a few years at the beginning of a mission. Meanwhile, one of your major power draws is a radio, which needs higher power as distance to Earth increases, later in the mission. Finally, nuclear thermal power supplies have decreasing power budgets over time. It seems reasonable to me that there's a combined power budget with focuses on ion propulsion for the first several years of a probe's lifetime, disabling the ion drive and shifting the (reducing) power budget to comms once target velocity is achieved.
Given that the rate of decay of the radioactive material in the RTG is constant the maximum mission time is set in stone from the beginning and can't be extended( i.e. it's a property of the material).
The private sector can't be expected to do everything, but the availability of Starship will change such high-velocity probes from "not affordable" to merely "somewhat expensive".
Most of the escape velocity of the voyager probes came from a gravitational slingshot around the gas giants. I don't think additional rocket power would help much.
Booster: let's assume an ideal state of 1 Raptor engine (3,300 lb) and 5,000 lb of other stuff before fuel
Plugging into the rocket equation and assuming no further staging, that gets us a delta v of 89,428 mi/hr, or about 2.3x the speed of Voyager 1. I'm not sure if we should add the orbital speed of Earth to that or not. Also keep in mind that the Voyagers reached their speeds thanks to several gravity slingshots, so in theory we could boost our Starship speedball probe even higher than that. If we used a fat Ion engine instead of chemical rockets, we'd get a lot more delta v as well (although over the course of years instead of a few minutes).
Ion engines is the only way a mission like this makes sense. Chemical rockets just don't cut it as much. Also what isp did you use? The vacuum raptor has significantly higher isp compared to the sea level one( and I'm not even sure that you can operate a sea raptor in vacuum).
One of the coolest science trips I made with my son, years ago, was to the Goldstone Deep Space complex in California.
We got treated to an incredibly indepth tour of the facility - including looking into the ruby maser equipment that amplifies the infinitesimally minuscule signal from voyager.
Truly one of the crowning achievements of the 20th century is to have successfully sent these two objects into deep space and keep in contact with them for over four decades!!
Thank you for this. Passed through Barstow several times but never knew this gem existed. Added to list of places to visit.
For me personally, I think the deep space probes are the finest examples of man's ingenuity. The use of math and physics to plan and plot something like the journey of the Voyager probes across decades, to actually see it in action and working just as predicted is an amazing thing.
Any information on how to visit? I tried visiting there as a spur of the moment thing when I was passing through Barstow. The military checkpoint personnel on the road to Goldstone were not happy and turned me away after a light questioning, checking driver license and license plate against databases, and visually inspecting the inside of the vehicle from outside with the windows down.
Thanks for this, years ago when I was on the road and wanted to visit last minute and quickly searched for information on where to go and tours, I didn't find this gem. Really helpful to see they have a visitors center in Barstow.
> The scientists who undertook this project knew it was the next generation that would benefit from the knowledge.
It's not such a black-and-white deal. The primary mission of the Voyagers was to study the outer planets, which it completed in ~12 years after launch. The studies on Jupiter and Saturn were already finished 5 years after launch.
Another thing I find interesting is that quite a few of the people working on Voyager have been there for 30+ years. I really enjoyed this article about Voyager and the people who work on it: https://www.nytimes.com/2017/08/03/magazine/the-loyal-engine...
Perseverance, James Webb ST, TESS, all come to mind. The common thread is that we're finding there's a lot to look at locally and with much higher fidelity than ever before, including Mars, Enceladus, and small bodies like Ceres, and bodies we've kind of written off, such as Venus. Even the Parker Solar Probe could fit this pattern. And that's not even including the stunning work in asteroid co-flying. The breadth of breakthrough research being done close to home is remarkable.
Re>> "The scientists who undertook this project knew it was the next generation that would benefit from the knowledge"
Yes. The scope/lifetime of the spacecraft was only to explore the outer planets. The scientists and engineers who designed and built it took it upon themselves to ensure it could stay within the budgetary constraints and exceed the mission scope. Everyone interested in Voyager should watch the documentary "The Farthest" - great documentary!
Plasma is still matter, in which electrons and atom nuclei are separated. They detect plasma because plasma particles are easy to detect due to being electrically charged. It doesn’t mean that there are no hydrogen and helium atoms out there - they are just hard to detect.
Would not the gravity of the solar system of pulled in much of the mass and what would be interesting is a probe sent directly up and down. Is this change in density a flat bubble of spherical, as in is the effect greater along the plane of the solar system.
That would provide the data to help nail this. Equally, what effect will this have upon the amount of matter in the universe and the hunt for dark matter/energy.
But logically, the gravity effect given the time of the universe, it is plausible that would be clustering (solar systems) and in-between those the viability of more matter in space and as such, density becomes plausible - so may explain what we are seeing here. Now what I'll be interested in is will the Voyager probes speed up, slow down or no change. The extra density will in theory slow them down, equally the weaker effects of gravity from the solar system would become less of a factor - might be they balance out for a period and may of already seen this. Still, value for money - Voyager is the gift that keeps on giving.
Now here is a thought, will the mass of the voyager probe in an environment in which it is the the most influential gravity start to build up these space particles. If that is so, who know's, the probes may well go on to attract enough mass that over billions and billions of years go onto form their own solar systems. Now that would be mind blown.
Ha, I had a similar thought, that what we perceive as the 'end' of our solar system, is but the end of the simulation. Why simulate a whole universe when you can just simulate one localized area, what we perceive of as the whole universe could just be 'fed' to us existing, while not really existing.
But the voyager probes too could ink out of existence, and the signals they're sending back wouldn't expand the map, they would just be hijacked by the simulation to send back whatver the devs wanted it to.
Laterally, I've often wondered if our increasing reliance on digital devices to observe and transmit data from probes and telescopes simplifies the effort required by alien actors concerned with limiting our development. If they can intercept our comms and edit them to their requirement, who knows what sort of 'universe view' they could feed us?
Perhaps the Great Silence is simply down to early Black Hat Aliens who've been feeding fictions to all civilisations that develop beyond straight to eye (etc) optical (etc) instruments?
I highly doubt that, I think the most likely 'Great Silence' is the vast energies required to go anywhere, the great filter stopping most civs from getting there (we've almost killed off earth and we're easily 300+ years from warp drives and interstellar travel).
I think the silence is just that: silence. We're it (right now).
Because of gravity, an entire civilization could live as long as we will on earth but on the right planet it could only take them 30 years per hour (like on interstellar where they were gone an hour on the planet, but off-planet 7 years passed.)
They could've started at the same time, but only be 10 years in, while we've transversed millenia.
Or could be exactly the same as how we evolved, except they did it 1 billion years ago, and died out 500 million years ago.
Top 3 contenders though for me for the fermi silence is: 1. Great Filter wins. 2. Time and Distance scales of space, and 3. We're living in a simulation. Aliens weren't part of the plan.
if alien life were out there, I don't think it'd just be content to hide out. I mean, look at our planet and the food chain, EVERY living thing competes for it's place on the food chain, and in the world. Extra-terrestrially I think we'd also compete w/ other races and see expansions.
If we lived 1 billion years, it's almost a certainty that we could colonize ALL of the milky way, and maybe other galaxies. Def. Andromeda since it'll merge with us soon enough.
Firstly, I also highly doubt it.
Secondly, I also think the Great Silence is down to something entirely mundane like our perhaps being the first out there.
That said - My point being - even if there is a tenth of a tenth of a tenth of a chance that my speculation is possibly not entirely incorrect, it then becomes of the utmost importance that going forward that we oblige ourselves in having some almost Monasterial-like utterly analogue back up where external input of first principles are wholly questioned; proved as much as possible from outwith the digital realm and then transcribed and stored in flesh, or by hand, or memory and voice. Elsewise, how do we know our ideas have not been interfered with?
I sometimes wonder if we shouldn’t send out a bunch of monoliths or something instead of directed energy. Maybe a pyramid of extremely flat faces with prime number ratio areas. If it gets near a star it will glint interestinlgly.
There is no “map”. The simulation would be like an entity-component system, basically a universal database. The voyagers coordinates are very far from Earth, but no new entities have to be created for that. Their coordinates can continue rising until they reach whatever the max possible value can be within the simulation, after that it would probably overflow into negative values and the voyagers would be on their way back toward where they started.
I've been having similar thoughts ever time I read about the incredible engineering and scientifical achievements of the first decades of Space Age. If we're living in a simulation, have the beings running it accounted for the development of interplanetary probes, people landing on the Moon, moon rocks being studied in the labs on Earth, full spectrum imagery from space telescopes? Or is every piece of data we're getting off-world is an equivalent of peeking into an out-of-bounds area in a game world? And if they have accounted for it, how fast was the insane pace of early Space Race compared to the estimations of outside observers?
Nah, they're just using infinite time to simulate fundamental quantum physics at the most basic level, so it doesn't matter what we do: https://xkcd.com/505/
The title is a bit misleading - this is not some density property of space-time, but more simply the density of electrons in space (average number of electrons/cubic cm).
> That it is not very dense doesn't change much here.
It does matter, because at some density there are no sound waves anymore. You can’t have sound waves if particles do not collide with each other. And also speed of sound goes down as density goes down. So for this extremely non-dense plasma it’s unclear how “sound wave” is defined.
That, again, doesn't change the speed of sound, only the maximal frequency / minimal wavelength of sound waves in the medium. In the intergalactic medium, only wave lengths longer than several light seconds are possible, but there is enough space for them to propagate.
Isn't the phrasing "density of space" a bit off? I mean a density is a scalar quantity of something per unit of space. So Density of Space would literally mean quantity of space per unit of space?
Reading the article it would make much more sense to say: Density of Matter in Space Outside of the Solar System.
The word "density" means mass per unit volume. It's sometimes qualified like "charge density" for (assumed, in turn, to be electric) charge per unit volume, but "density of charge" would mean mass per unit volume of charge, like "density of iron", means mass per unit volume of iron.
So density of space is mass per unit volume of space, not space per unit volume.
Completely talking out of my ass here but those electrons making up the density of matter in inter-stellar space, could they be what is causing CMB radiation?
Seeing as energy is never lost, they just bounce around interstellar space until caught up in a heliosphere of a star system.
Either way I love how the Voyager probes are literally giving us first real impressions of the universe beyond theories.
88 comments
[ 3.2 ms ] story [ 64.8 ms ] threadSince we know exactly what we're looking for and exactly where it should be, we have all kinds of neat radio tools to bring to bear on sampling a faint signal from interstellar noise.
Eventually, its power source will die out, its components will fail, or enough cosmic rays or debris will corrupt enough of its systems it can no longer transmit.
Given those factors, I do wonder what the expected lifetime of the probe is, with the power source being the most clear "game over" line.
It appears that both Voyagers are slated to have some experiments disabled soon (2020 and 2021) to best use remaining power from the RTGs, but since the RTGs are nuclear sources, the decay rate is independent of power draw (it's more an issue of switching off the experiments to avoid peak draw killing the ship).
Voy1's expected to lose too much wattage to turn on the radio by 2025; I can't find a quick number for Voy2.
EDIT: It appears Voy2's power package was expected to allow mission operation through 2020, so sayeth Wikipedia; no idea if that implies the radio was expected to die this year or this was the year the craft would need to be reconfigured for a scaled-back mission profile to maintain enough power for attitude control and radio transmission.
I believe it's expected that they'll need to pretty much turn off all of the instruments in the next 5 years, and after that it can run it's comms a bit longer but nothing else.
Edit: found an FAQ page from JPL about the Voyagers:
https://voyager.jpl.nasa.gov/frequently-asked-questions/
It looks like this year they need to start shutting down instruments more aggressively, expect to be able to run at least once instrument until 2025, and then there's a possibility of the voyagers staying contactable until 2036 with no instruments running.
To see one application of this information, look for discussions of the "Pioneer Anomaly". That particular effect is now understood, but had it held up to detailed systematic-effect analysis, it would have affected our understanding of gravitation on solar-system scales.
When one enters entirely new territory, the understanding derived from single reliable measurements can be quite substantial.
If the probes still had enough power by then, the current DSN would be able to receive data until the mid-2030's.
Digital formats, error correcting codes, wide band (to avoid narrow occlusion from stopping us from recieving), redundancy of transmissions, long bit frames that allow us to average our readings (at the cost of bitrate, akin to long exposure photography)
https://electronics.stackexchange.com/questions/321186/is-it...
If that isn't much, run slower and coherently combine more data. White noise power with averaging will fall with the reciprocal square root, while your coherent signal power will add linearly-- eventually you overcome the noise assuming your transmitter/receiver oscillators are locked well enough to sum coherently.
If the noise is not white, e.g. if there are tones in it-- these steps work less well.
Now consider how direct sequence spread spectrum works:
I take a slow signal-- like a 50 bit per second 100Hz wide BPSK signal-- and spread it out by xoring it with a fast random sequence (say a 1MHz random sequences).
The result looks like noise. But if you xor it again you get the original signal back.
When you transmit it, the receiver gets a sum of your signal and noise sources. We can analyize each separately: If you xor white noise with your random sequence -- nothing much happens: you end up with white noise with the same power. So when the receiver xors the received signal with the random sequence, as mentioned nothing much happens to white noise. But any tonal noise gets converted into white noise (because it is independent of the random sequence), and your transmitted signal is recovered and ready for reception using a narrow locked filter.
Modern digital communication almost always uses error correcting codes which allow perfect reception even when some bits are corrupted (early space probes were among the first applications of powerful error correcting codes).
https://en.wikipedia.org/wiki/Matched_filter
They allowed to reach crazy signal/noise ratios.
Also it's important to note that Starship isn't really optimized for such missions due to its high dry mass. It's made to bring a lot of mass to orbit cheaply, not really to accelerate it very fast.
Anyway, yes, of course there are countless variations that can be done to make it work. Sticking a Centaur or two in a Starship also seems to be viable. But the parent comment specifically asked about Super Heavy/Starship here.
Starship estimated payload to LEO: 100 t
Voyager mass: 1,820 lb
Booster: let's assume an ideal state of 1 Raptor engine (3,300 lb) and 5,000 lb of other stuff before fuel
Plugging into the rocket equation and assuming no further staging, that gets us a delta v of 89,428 mi/hr, or about 2.3x the speed of Voyager 1. I'm not sure if we should add the orbital speed of Earth to that or not. Also keep in mind that the Voyagers reached their speeds thanks to several gravity slingshots, so in theory we could boost our Starship speedball probe even higher than that. If we used a fat Ion engine instead of chemical rockets, we'd get a lot more delta v as well (although over the course of years instead of a few minutes).
We got treated to an incredibly indepth tour of the facility - including looking into the ruby maser equipment that amplifies the infinitesimally minuscule signal from voyager.
Truly one of the crowning achievements of the 20th century is to have successfully sent these two objects into deep space and keep in contact with them for over four decades!!
For me personally, I think the deep space probes are the finest examples of man's ingenuity. The use of math and physics to plan and plot something like the journey of the Voyager probes across decades, to actually see it in action and working just as predicted is an amazing thing.
What probes are we sending to reach the same heights as Voyager for the next generation of scientists?
https://en.m.wikipedia.org/wiki/Voyager_program#/media/File%...
It's not such a black-and-white deal. The primary mission of the Voyagers was to study the outer planets, which it completed in ~12 years after launch. The studies on Jupiter and Saturn were already finished 5 years after launch.
Yes. The scope/lifetime of the spacecraft was only to explore the outer planets. The scientists and engineers who designed and built it took it upon themselves to ensure it could stay within the budgetary constraints and exceed the mission scope. Everyone interested in Voyager should watch the documentary "The Farthest" - great documentary!
- ed ignore this, I actually RTFA - it's talking about plasma, not itty-bitty matter!
That would provide the data to help nail this. Equally, what effect will this have upon the amount of matter in the universe and the hunt for dark matter/energy.
But logically, the gravity effect given the time of the universe, it is plausible that would be clustering (solar systems) and in-between those the viability of more matter in space and as such, density becomes plausible - so may explain what we are seeing here. Now what I'll be interested in is will the Voyager probes speed up, slow down or no change. The extra density will in theory slow them down, equally the weaker effects of gravity from the solar system would become less of a factor - might be they balance out for a period and may of already seen this. Still, value for money - Voyager is the gift that keeps on giving.
Now here is a thought, will the mass of the voyager probe in an environment in which it is the the most influential gravity start to build up these space particles. If that is so, who know's, the probes may well go on to attract enough mass that over billions and billions of years go onto form their own solar systems. Now that would be mind blown.
But the voyager probes too could ink out of existence, and the signals they're sending back wouldn't expand the map, they would just be hijacked by the simulation to send back whatver the devs wanted it to.
Perhaps the Great Silence is simply down to early Black Hat Aliens who've been feeding fictions to all civilisations that develop beyond straight to eye (etc) optical (etc) instruments?
I think the silence is just that: silence. We're it (right now).
Because of gravity, an entire civilization could live as long as we will on earth but on the right planet it could only take them 30 years per hour (like on interstellar where they were gone an hour on the planet, but off-planet 7 years passed.)
They could've started at the same time, but only be 10 years in, while we've transversed millenia.
Or could be exactly the same as how we evolved, except they did it 1 billion years ago, and died out 500 million years ago.
Top 3 contenders though for me for the fermi silence is: 1. Great Filter wins. 2. Time and Distance scales of space, and 3. We're living in a simulation. Aliens weren't part of the plan.
if alien life were out there, I don't think it'd just be content to hide out. I mean, look at our planet and the food chain, EVERY living thing competes for it's place on the food chain, and in the world. Extra-terrestrially I think we'd also compete w/ other races and see expansions.
If we lived 1 billion years, it's almost a certainty that we could colonize ALL of the milky way, and maybe other galaxies. Def. Andromeda since it'll merge with us soon enough.
That said - My point being - even if there is a tenth of a tenth of a tenth of a chance that my speculation is possibly not entirely incorrect, it then becomes of the utmost importance that going forward that we oblige ourselves in having some almost Monasterial-like utterly analogue back up where external input of first principles are wholly questioned; proved as much as possible from outwith the digital realm and then transcribed and stored in flesh, or by hand, or memory and voice. Elsewise, how do we know our ideas have not been interfered with?
Wouldn't that require the devs to simulate whatever code we put on the probe? Did you just discover an attack vector for hacking the simulation?
But what a concept though, how can a space-time be denser than any other? I’m not versed in this, maybe it can?
Can someone tell me what "supersonic" means in a near vacuum?
>I assume it's being compared to the speed of sound through Earth's air.
That roughly 1.2 km/h in space that is nothing. Solar wind are like a 1.6 million km/h
It does matter, because at some density there are no sound waves anymore. You can’t have sound waves if particles do not collide with each other. And also speed of sound goes down as density goes down. So for this extremely non-dense plasma it’s unclear how “sound wave” is defined.
Reading the article it would make much more sense to say: Density of Matter in Space Outside of the Solar System.
So density of space is mass per unit volume of space, not space per unit volume.
It felt like saying “the velocity of distance”
Seeing as energy is never lost, they just bounce around interstellar space until caught up in a heliosphere of a star system.
Either way I love how the Voyager probes are literally giving us first real impressions of the universe beyond theories.