I'm amazed that Voyager is still sending us data. It had to travel a a bajillion (+/- 100) km and not get blasted by some flying scrap of rock. It's components had to withstand every form of radiation our solar system has to offer, and the signals themselves had to make it all the way back to Earth without degrading beyond use. Wow!
Still, I'm worried that the tools of the 80s are not going to be sufficient to provide the details we'd need to understand what happens at the edge of the solar system.
For my part, I hope that we find some of those hidden dimensions, and it turns up on the other side of the solar system in a couple weeks.
>and not get blasted by some flying scrap of rock.
I think a lot of people don't understand the scale of space. It's really, really empty. The chance of being intercepted by any solid matter is incredibly low. I can't even make any reasonable analogies to distances on Earth, it's so extreme.
The mean density of the universe is something like 3-6 atoms per M³. When you consider the number of atoms in your typical cubic meter of matter — you, the ocean (water is ~10²² molecules per cubic centimeter), a mountain, let alone things like stars, where most of the matter in the universe is, anyway — that should give you a rough idea of just how empty space actually is.
These aren't the tools of the 80s, they're the tools of the early 70s at best, probably closer to late 60s. The vast majority of technology used in NASA missions has to have been used for about 10 years so that there is a detailed and verified data set about reliability. And then they over estimate.
That's the reason why Voyager still works and why one of the first two Mars rovers is still chugging along, way past expected mission life (and the second one also died recently, way past mission life)
V'ger made it out of Earth's orbit before we made it unsafe (http://en.wikipedia.org/wiki/Space_debris) and the rest of space is like driving from Calgary to Edmonton, but with more to look forward to.
I love the Voyager program, its great science and its paid back many times its investment in knowledge. But the writing at Wired could use some help. The things that bug me most were calling particles in space "supersonic" (what does that even mean when you have no atmosphere to carry sound?) and that they "carried the magnetic field" as opposed to "the motion of these charged particles generates a magnetic field."
That said, I look forward to future updates from the science team and the space craft doesn't run out of juice before it runs out of things to report on.
There's something in the comments about this (the supersonic part, anyways). Apparently they are referring to the speed of sound in the solar wind "...which is roughly 220,000 mph".
Huh. Makes sense, but I wouldn't have thought of that. That's non-obvious enough that it would have been worth a mention in the article.
Except if the exploding star has no life anywhere near it, it has no ability to cause any actual death. I don't disagree that if something were (hypothetically) living in its blast radius, it would be killed, just that if nothing (hypothetically) were so living, it can't really be capable of killing said hypothetically non-existing things.
It's been announced that Voyager 1 has left the solar system so many times, I didn't expect to read an article that said Voyager 1 hadn't even left the solar system at all yet!
Yeah, but none of those announcements have come from NASA. In fact, one of the recent solar system exit announcements triggered NASA to publish a press release [1] to let everyone know that Voyager 1 has, in fact, NOT left the solar system and all these announcements are wild speculation by people who don't directly work on the Voyager 1 team.
My understanding is that as soon as the magnetic field shifts, Voyager will be declared to have "left the solar system".
The solar wind has died down, the cosmic rays have increased (although they are unexpectedly coming from a single direction), and the magnetic field shift will be the third and final necessary event.
And they expect it soon (could be months or years).
"To all intents, cosmic rays arrive evenly from all directions in the sky, but this does not necessarily mean their sources are evenly spread around us. More likely, they are constantly deflected and scattered by magnetic fields in the galaxy, until any trace of their original motion is lost."[0]
A crude hypothesis would be that there's some sort of magnetic field that is directing them from a single location. Since we've never been this far before, its a pretty huge guess...
We don't know the edge yet. we are discovering it. It's a frontier. So how do you cross something that you don't even know the size of. All the announcements are of different definitions of the edge. There are many edges.
Hopefully they have plenty of checks and tests to make sure this isn't the case, but having no knowledge of the details and simply reading this article, my thoughts at several points ran to "conspicuous instrumentation failure."
Granted, it's totally reasonable that we should either not know what to expect or simply expect the wrong thing, having never been out that far. I just can't help wondering how much we can do to confirm what's being reported is based on valid readings (and, of course, whether that confirmation is being done before the PR people send it out into the media microcosm).
That was my suspicion as well after reading this article. We really need to wait until more data is gathered - or better still, another probe enters the area - before making any grand pronouncements.
> The sun produces a plasma of charged particles called the solar wind, which get blown supersonically from its atmosphere at more than 1 million km/h.
On earth, that'd be 'supersonic', by a "slim margin". But what's that even mean in space?
It’s not a perfect vacuum; there are particles — so there is some speed at which pressure waves propagate through the medium. That’s the speed of sound. Speeds faster than that speed are "supersonic”.
Currently the 2nd comment on the page of article addresses that.
Actually, supersonic simply refers to anything moving faster than the speed of sound in a particular medium. The Earth's atmosphere has a particular speed of sound but so does the solar atmosphere and wind. Apparently, the speed of sound in the solar wind is roughly 220,000 mph. Supersonic and subsonic are the terms that scientists use to describe such things.
Perhaps I'm biased by my own ignorance, but the speed of sound in the solar wind (or the fact that terms like "speed of sound" still make sense in an ostensible vacuum) seems like the sort of thing a reasonable person might not know. If science writing is to be accessible to the layperson, an explanatory parenthetical (even just clarifying the approximate speed at which the subsonic wind was traveling) would have been helpful.
"The models that have been thought to predict what should happen are all incorrect"
A bit off topic, but that's why you should never ever draw conclusions from models.
Use a model to guide research (i.e. tell you where to look), but never consider the model as an answer.
I see far too many papers published based on models. This should not be accepted, this is not science.
It doesn't matter if the model is the only available thing. If you have no other way of getting information then you must admit defeat (hopefully temporary), but never give in and start believing your models.
That's not how science works. Everything we "know" is a model, an approximation. Model that describes how the world works to some degree. Molecules aren't rigid balls but a model like that works on some scales. For protein folding atoms are considered rigid balls because the model works for what we need it.
All hypothesis are basically models. Later they are confirmed by experiment and they become a scientific theory. You can definitely draw conclusions from a model and then verify them with an experiment. Which is just what the Voyager is doing
A model in science is a mathematical description that maps inputs to outputs. Science is an iterative process that first hypothesises a model then tests it through experimentation. Over time a model may be refined or perhaps superceeded by a superior model with different foundations. A model then is never considered 100% accurate for all cases, there is always the potential for new observations to lie outside the model.
If you were to be sending a probe to the edge of the solar system, what exactly would you use to plan and predict its journey if not models then? Would you wait until you have a way to measure what happens at the edge of the solar system before sending out your probe to measure it?
The entirety physics is essentially a model. If you want to completely know everything before you start trying to do anything, you'll get anything done.
> what exactly would you use to plan and predict its journey
I guess you didn't read what I wrote. I will quote again for you: "Use a model to guide research".
> Would you wait until you have a way to measure what happens at the edge of the solar system before sending out your probe to measure it?
By all means - send out the probe. But until the probe returns data do not publish any papers purporting to know what the edge of the solar system looks like.
> The entirety physics is essentially a model.
No. It started as a model (or idea), but every single step was confirmed using the actual world, and not a model.
> If you want to completely know everything before you start trying to do anything, you'll get anything done.
Next time read what you are replying to so you can give a better response.
This I'll concede. I misinterpreted your point and tone as "don't rely on anything you haven't already measured". I would also agree that it's rather grating to read things that say "X totally happens (according to model Y)". But I don't think that it is inherently bad for one to say "Model Y predicts X".
> No. It started as a model (or idea), but every single step was confirmed using the actual world, and not a model.
This however, I do disagree with. It's still a model. It wasn't "confirmed"; it was "not disproven". Physics will always be a model. I don't see the problem with saying "this model turned out to be wrong so we need to come up with a better one" (exactly what's happening in the article). A large number of important breakthroughs in physics were from scientists demonstrating the failures of models or running into them accidentally (see caloric theory and the Michelson–Morley experiment).
> But I don't think that it is inherently bad for one to say "Model Y predicts X".
I do. Not because the sentence in and off itself is bad, but rather because when the sentence is repeated it gets changed to "We know X because of Y."
> Physics will always be a model.
Maybe we have different meanings for the word model.
I suspect you are using the word model like a "model car". i.e. a description of what something is.
I mean it in the term of "model these variables", ie. use a computer to put in variables and hope you programmed everything correctly and get a result of what will happen.
I'm not using it in the descriptive sense, but rather the action sense.
> I don't see the problem with saying "this model turned out to be wrong so we need to come up with a better one" (exactly what's happening in the article).
Nothing wrong with saying that, but that's not what actually happened. Instead the model of the boundary was taught as fact (for example I expect that if you read the wikipedia article on it from 5 years ago it would talk as if we had a pretty good idea of what the boundary looked like).
If, it was simply used to decide which experiments to prioritize on the spacecraft that would be fine. But that's not all that the model was used for.
I'm sure in the original they were careful to call it a model, and an idea, etc. But in wider use (even scientific articles) it was understood as fact.
"But until the probe returns data do not publish any papers purporting to know what the edge of the solar system looks like."
I'm pretty sure that no decent scientist ever 'purports to know' what the edge of the solar system looks like - they are merely using what evidence they have available to make an educated guess and try to get a workable model of it.
This is how science works.
You make a model, test it and finds the evidence does not fit your model. You then modify your model.
Also, you seem to be suggesting that all of, say, theoretical physics is necessarily worthless. What about pure maths? String theory? All of these things are just models, and have no basis in reality. What of them?
Hypothesis -> Observe -> Hypothesis -> Repeat. You even learn it at school where they make you give a Hypothesis before running the experiment, instead of after.
The Bible? Ok, I jest.
You observe nature. For instance, that apple that just fell. Then you make predictions about why it fell down and not up or sideways. You hypothesize that this apple and all apples fall at the same rate, call it 5m/s.
You then observe that if it fell from higher up, it is traveling faster than if it fell from a lower branch. Your first model was wrong. Time to revise your model.
Then you invent new mathematics to explain what was wrong about your model and call it the Calculus. With calculus, you hypothesize that it can predict how fast it would be falling if it fell from a completely different height fit constants that match your first and second observations. You then observe that an apple at another completely different height matches your prediction.
Now go and observe other things and hypothesize about them too.
With regards to the Solar System, you observe that the Earth has an atmosphere and observe that it has a magnetic field that affects particles coming towards it from space. You hypothesize that the Sun has significant influence on particles further away from Earth.
In your planetary travels, you observe that there seems to be data that supports your model. You hypothesize that eventually, the Sun will lose its influence and interstellar space will be radically different, that at some point the solar winds generated by the Sun will fall off.
This is more or less where we are now, but we observe that the edge isn't quite as we predicted it would be. This could be because we haven't left the heliosphere yet, or it could be that our model was wrong. We are currently collecting those observations that will allow us to refine our models, and with any luck, the revised model will be tested by the next Voyager.
Observe, Predict, Observe. Even with the next Voyager, we won't know for sure that our model is correct, but it gives you a starting point.
Hm, is there a terribly important difference? I'm not in "formal natural science" so I don't know how it goes in the real world.
But I would think that if you're being honest with yourself and your results in the "observe" state, regardless of whether or not you had an existing hypothesis, you would draw the same conclusions.
I suppose if you intentionally set out to ONLY observe before hypothesizing, you might eliminate some unintended bias or something.
The difference is if you hypothesize you will look for something to confirm or deny your hypothesis.
But if you simply observe you will find out what there is.
It's an issue of imagination.
Also for students it makes them try to predict the results of the experiment - which is utterly pointless. Simply do the experiment and find out - that's the whole point, science is about experimenting, not just coming up with ideas.
Seems perfectly explained by the fact that the craft has just exited a huge "balloon" (it's a metaphor, for any nitpickers) formed by the solar wind. The lack of intergalactic particles from the sunward direction could be simply because the craft is in the balloon's shadow.
I love the wonders of space, I grew up watching Star Trek Voyager. What continues to amaze me, is the drone programs we have, I just wonder when we'll start advancing our drone programs for space.
Ever since I was young I used to think aliens existed, but that aliens used some type of biorobot to explore. Kind of like we do with rovers, and satellites...just not in the image of us.
This was launched 36 years ago, and still sending data! How did they make it that sturdy back then? Do they still make them like that today?
Is there actually any mission at all with the intention to have a new spacecraft leave the solar system, or is it just a coincidence with the voyagers and now all missions are only for planets?
The MER rovers (Opportunity and Spirit) are quite remarkably reliable too. Not 36 years reliable, but they are operating in far more hostile environment.
Opportunity remains active as of 2013, having already exceeded its planned 90 sol (Martian days) duration of activity by 9 years, 62 days (in Earth time). Opportunity has continued to move, gather scientific observations, and report back to Earth for over 37 times its designed lifespan.
It was launched in 2006, and passed by Jupiter in 2007 (to do some experiments, photos and gain speed). It will pass by Pluto in 2014 and will take the firsts detailed photos of Pluto.
It will reach 100 AU in 2038 (Voyager 1 is a little more far away) so to see what is happening there using current technology we will need to wait ...
Still, I'm worried that the tools of the 80s are not going to be sufficient to provide the details we'd need to understand what happens at the edge of the solar system.
For my part, I hope that we find some of those hidden dimensions, and it turns up on the other side of the solar system in a couple weeks.