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Ladies and gentleman, Voyager I has just left the building..
October 7, 2012 9:09 AM   Subscribe

All evidence is pointing to the fact that Voyager I has left our solar system. New data from the spacecraft, which I will discuss below, indicate Voyager 1 may have exited the solar system for good. If true, this would mark a truly historic moment for the human race — sending a spacecraft beyond the edge of our home solar system
posted by KevinSkomsvold (89 comments total) 41 users marked this as a favorite

 
"For good" was kind of assumed.
posted by Egg Shen at 9:11 AM on October 7, 2012 [4 favorites]


Someone didn't see the original Star Trek movie.
posted by ChurchHatesTucker at 9:12 AM on October 7, 2012 [35 favorites]


...AND STAY OUT!!!
posted by eriko at 9:14 AM on October 7, 2012 [26 favorites]


What I find more incredible than the fact that an object that we slingshotted around several planets to gain speed is actually leaving the solar system within my lifetime....

...is that we are still able to hear its feeble radio signal and collect data from it across these incredibly fast distances and against all the background radiation.
posted by hippybear at 9:19 AM on October 7, 2012 [27 favorites]


Next stop ............................
posted by Artw at 9:22 AM on October 7, 2012


But...but...it said it would be right back. It just had to run down to the store. For smokes...or something...
posted by Thorzdad at 9:23 AM on October 7, 2012 [7 favorites]


Any minute now it runs into the dark matter...
posted by Segundus at 9:26 AM on October 7, 2012 [3 favorites]


All evidence is pointing to the fact that Voyager I has left our solar system.

But seriously. Defining "the solar system" is hard, and I don't think calling it at the heliosphere is a good one. Yes, 120+ AU out is a goodly way, but there are many scattered disk object well beyond 100AU, and the Inner Oort Cloud is currently thought to be in the 1000-5000AU range, with a halo outer Oort cloud at 50K AU, nearly a lightyear out.

90377 Sedna, clearly a solar system object, orbits between ~78 AU and ~960 AU, clearly much farther than Voyage I currently is. Exactly how to classify Sedan is a matter of debate, the biggest problem being we've not found many like it. The closest is "Extended Scattered Disk Objects", but there are only 9 in the category, and only two that have aphelions on the order of Sedna (the other being 2007 TG422, as yet unnamed.)

So, out of the solar system? No. A tremendous achievement, reaching the heliopause? Yes.
posted by eriko at 9:26 AM on October 7, 2012 [21 favorites]


What?
posted by notreally at 9:33 AM on October 7, 2012 [4 favorites]


The heliopause is a perfectly good place to call "the edge" of the solar system. It's the point where the radiation from the sun is no longer the dominant force and the general cruft of the neutral universe takes over. If the radiation from the sun isn't the main active force, then it can quite clearly be stated that you've left the system.
posted by hippybear at 9:36 AM on October 7, 2012 [6 favorites]


I dunno, eriko. It's kinda like arguing over where the Pacific Ocean ends and the Atlantic Ocean begins.

Let's just draw the line at Cape Horn (Heliopause).
posted by notyou at 9:39 AM on October 7, 2012 [2 favorites]


I think this probably is the sixth time a press release has announced that Voyager I is leaving / has left / has reached the edge of the Solar System. I like the definition that says that the Solar System is everything gravitationally bound to the Sun, but that rules out several things in and around the planets a bit non-intuitively—including Voyager I after its slingshot around Saturn, when it achieved escape speed.

There really isn't a widely-agreed upon definition of "solar system," though. They really should say Voyager is leaving he heliosphere, which does have a boundary that everyone can agree on.

90377 Sedna, clearly a solar system object, orbits between ~78 AU and ~960 AU, clearly much farther than Voyage I currently is. Exactly how to classify Sedan is a matter of debate...

Well it's not a coupe, I think we can all agree on that. (Sorry, eriko, couldn't resist.)
posted by BrashTech at 9:39 AM on October 7, 2012 [5 favorites]


If the radiation from the sun isn't the main active force, then it can quite clearly be stated that you've left the system.

I'm inclined to agree.

That there are farther-out objects gravitationally bound to the sun doesn't seem relevant when Voyager itself is not.
posted by Egg Shen at 9:40 AM on October 7, 2012


Next stop ............................

somewhere Palmer Eldritch is waiting ... or whatever used to be Palmer Eldritch.
posted by philip-random at 9:53 AM on October 7, 2012 [4 favorites]


I think this probably is the sixth time a press release has announced that Voyager I is leaving / has left / has reached the edge of the Solar System.

Yeah, we've been in this "edge of the universe" discussion since June, and probably earlier. Without the magnetic field direction changing, we're still about at the same point as then, right? Ah, it's all blurry at the edges, anyway.
posted by mediareport at 9:54 AM on October 7, 2012


Voyager 1 has apparently now reached the position where it cannot accidentally hear or see Psy's Gangnam Style, nor any Gangnam Style parody video. That's probably as good a mark as any that it's now fled the solar system. #OppaHeliopauseStyle
posted by Wordshore at 9:56 AM on October 7, 2012 [25 favorites]


Here's a Space.com article from early September: Voyager 1 Spacecraft Farther From Solar System's Edge Than Thought

...Scientists thought that by now Voyager 1 would start to see the solar wind deflected from its straight outward path into a more northward or southward manner as it curved to form the heliopause. Now researchers using data from the Voyager 1 spacecraft find the probe is not yet close to the heliopause. "The implication is that the flow of solar wind plasma in the heliosheath is more complex that we had expected," study lead author Robert Decker, a space physicist at Johns Hopkins University, told SPACE.com.

Decker and his colleagues requested that the Voyager project team rotate Voyager 1 periodically to see if the solar wind was in fact getting deflected in a northward or southward manner. They found no evidence of deflection in the zone the probe was zipping through.

It remains uncertain how much farther outward the transition region extends, researchers say. As to when Voyager 1 might actually leave the heliopause, "opinions vary on this," Decker said. "Based on the changes we have seen in the Voyager 1 data during the past year, I would expect that Voyager 1 will cross the heliopause within one year."


So, yeah, very cool and wonderful and SPACE!! and all, but still blurry.
posted by mediareport at 10:01 AM on October 7, 2012 [2 favorites]


To phrase it even more broadly, astronomers have a huge problem with "edges" in general. There's really no way to get a bunch of astronomers to agree on the "edge" of the solar system, or the edge of the galaxy, or the local group, or any other galaxy, or the edge of a cluster of galaxies, etc., and that means we actually do have fights about what should be considered "in" and what should be "out" in any particular context. This is actually important when studying galaxies, since if you want to know the mass of a galaxy, you need to decide where it "ends", otherwise the mass is unbounded. But all of the definitions of the "edge" of a galaxy are contrived, and sometimes you might think you're seeing some effect which is a function of the galaxy's mass, but really it's just an effect of where you define the outer edge of the galaxy, which can vary in all sorts of confusing ways. More locally, there's certainly no good boundary between Earth's atmosphere and "space". Even the "surface" of the sun is pretty contrived; at least there you can make a decent optical depth argument, but even that's a little misleading since we usually define a "surface" based on density, not optical depth.
posted by kiltedtaco at 10:10 AM on October 7, 2012 [6 favorites]


New data from the spacecraft, which I will discuss below, indicate Voyager 1 may have exited the solar system for good.

That's fine, but how much longer is it going to take until it finally finds water?
posted by Anything at 10:19 AM on October 7, 2012 [2 favorites]


The whole notion of "edge of the solar system" is a poetic one. It's OK if it's not precise or entirely accurate.

I like how the particle rate had some previous dips. It reminds me a bit of the interface between a harbour and the open water, with the chop and turbulence at the boundary.
posted by Nelson at 10:23 AM on October 7, 2012 [3 favorites]


Next stop ............................

LV 223!
posted by phaedon at 10:25 AM on October 7, 2012


I think of Voyager 1 is the extent of the senses the technological singularity. We are as big as Voyager 1 can reach.
posted by humanfont at 10:26 AM on October 7, 2012 [4 favorites]


To phrase it even more broadly, astronomers have a huge problem with "edges" in general.

Which explains why they arrive at the observatory with tiny scraps of toilet paper stuck to their faces.
posted by George_Spiggott at 10:39 AM on October 7, 2012 [4 favorites]


Amazing that a machine built more than 35 years ago is still running and sending back data.
posted by octothorpe at 10:42 AM on October 7, 2012 [9 favorites]


Well, we know from what we can see through telescopes where these boundaries are illuminated, they can be quite turbulent and chaotic. We are hoping to collect exactly two datapoints on what might turn out to be similar to trying to measure the depth of the Pacific Ocean to a resolution of 1 millimeter.

Still, the way the solar protons crashed so quickly is impressive.
posted by localroger at 10:46 AM on October 7, 2012


Aww heckers, as long as it's just far enough out to let our galactic overlords know that we are ready for the gift of FTL drive and the contingent membership in the Lensmen League.
posted by sammyo at 10:46 AM on October 7, 2012


And then it hits a wall painted to look like the entire universe, and a door opens and Ed Harris peeks in and is all DAMMIT THEY CAUGHT US.

i forget the rest of that movie
posted by elizardbits at 10:59 AM on October 7, 2012 [6 favorites]


I don't mind hearing about this several times, it's always awesome, and wow, that second graph. I just had the image flash into my head of diving into the sea when it's raining - all noise and spatter around, then a splash and sudden quiet.

> Which explains why they arrive at the observatory with tiny scraps of toilet paper stuck to their faces.

I um, initially thought that this was a joke about them not knowing where their assholes stopped, and so they would keep wiping until they converged at the other "pole". It's about shaving, right?

posted by lucidium at 11:11 AM on October 7, 2012 [3 favorites]


We'll only know for sure when we see the first Dairy Queen. That's how I know I'm out in the suburbs.
posted by benito.strauss at 11:15 AM on October 7, 2012 [1 favorite]


and wow, that second graph.

I just realized, looking back at that graph, that my comparison to measuring the depth of the ocean to a resolution of 1 millimeter might be more exact than I realized. During the month before the final crash there were two multi-day deep minima in the data, which suggests that the boundary could be moving back and forth a bit faster than the spacecraft is moving.

Also, while not as spectacular the first graph has two slight but noticeable maxima that coincide with the deep minima in the second.
posted by localroger at 11:17 AM on October 7, 2012


If the radiation from the sun isn't the main active force, then it can quite clearly be stated that you've left the system.
I'm inclined to agree.

That there are farther-out objects gravitationally bound to the sun doesn't seem relevant when Voyager itself is not.
I don't see what one has to do with the other. The heliopause is just where the pressure caused by stuff flying out of the sun has decreased low enough to be matched by the pressure of external stuff.

Meanwhile if the definition of being in the solar system is being "gravitationally bound to the sun", then Voyager 1 hasn't been part of the solar system since, what, 1980 or so.
posted by Flunkie at 11:26 AM on October 7, 2012 [1 favorite]


I'm calling it Elvis now.
posted by yoga at 11:30 AM on October 7, 2012 [2 favorites]


+---------------------+
|       NEXT GAS      |
| 9.3 TRILLION MILES  |
+---------------------+

posted by mazola at 11:42 AM on October 7, 2012 [18 favorites]


Voyager should just report when it stops seeing Waffle House signs by the exit.
posted by Rhomboid at 11:46 AM on October 7, 2012 [1 favorite]


And don't let the heliopause hit your ass on the way out, you glorious metal bastard.
posted by zippy at 11:47 AM on October 7, 2012 [6 favorites]


If a bunch of nitwits like us can send something beeping out of the solar system it is not good that we haven't found anyone elses calling card.
posted by shothotbot at 11:48 AM on October 7, 2012 [1 favorite]


> "Meanwhile if the definition of being in the solar system is being 'gravitationally bound to the sun', then Voyager 1 hasn't been part of the solar system since, what, 1980 or so."

I don't actually care what the definition is, but this is kind of a silly point to make. Earth's atmosphere goes until the furthest extent of the gases that are gravitationally bound to earth. Something is "within earth's atmosphere" if it's within those gases, even if it's on the way out. Until it does, it's still inside.

If the definition of the solar system is the furthest extent of objects that are gravitationally bound to the sun, then Voyager is within the solar system until it gets past that last object.
posted by kyrademon at 11:49 AM on October 7, 2012 [1 favorite]


Amazing that a machine built more than 35 years ago is still running and sending back data.

They don't make 'em like they used to. My 2011 model Voyager barely made it past Mars before the transmission gave out.
posted by Behemoth at 11:57 AM on October 7, 2012 [2 favorites]


kyrademon, I'm not defining the solar system, and I'm certainly not making the point that Voyager 1 hasn't been part of the solar system since 1980.

I'm making the point that the person I was responding to seemed to be agreeing in one breath to a definition of "out of the solar system" as being "out of the heliopause", and in the next breath asserting a definition of "out of the solar system" as being "not gravitationally bound to the sun". These two definitions are not even remotely the same thing as each other.
posted by Flunkie at 11:57 AM on October 7, 2012


I hate the state of science in America these days :(

The money quote from the article was :

"At last check, NASA scientists said they were not yet ready to officially declare that Voyager 1 had officially exited the solar system by crossing the heliopause."

Which was turned into blogger Eric Berger's personal interpretation based on his look at the facts that : "More evidence that Voyager has exited the solar system" which gets translated to Metafilter as : All evidence is pointing to the fact that Voyager I has left our solar system

Darwin Wept.

In fact , Berger's very own article points out that only 2 of the 3 criteria that NASA wants are being met - the third is in dispute so by no means has all evidence been met.

Interesting article but presented factually inaccurate here at MeFi.
posted by Podkayne of Pasadena at 12:00 PM on October 7, 2012 [2 favorites]


"Lessee...put a hold on the mail, check; turn off the iron, check; feed the cat...awww dammit!"
posted by Greg_Ace at 12:03 PM on October 7, 2012 [1 favorite]


Next stop ............................
posted by Artw


An appreciation for how large and empty the universe actually is?
posted by benito.strauss at 12:08 PM on October 7, 2012 [1 favorite]


This time they mean it.
posted by Burhanistan at 12:16 PM on October 7, 2012


shothotbot: space is big.

This is an understatement. Understatements here are sadly unavoidable.
posted by edd at 12:18 PM on October 7, 2012


Almost completely incomprehensible. I mean, I understand all the words, but it's really madness. Hooray science!
posted by Glinn at 12:21 PM on October 7, 2012 [1 favorite]


yeah, if you want to get an idea for the scales involved here, and you have an iOS device, download Exoplanet and zoom out from the sun in the milky way view. voyager 1 and 2 are in the program's database... voyager is absolutely nowhere near even the closest stars. not by a longshot. it's insane how big the observable universe is. even if the galaxy is teeming with life there's a good chance we'll never cross paths, unless they or we figure out how to 'fold' spacetime.
posted by joeblough at 12:25 PM on October 7, 2012 [1 favorite]


Voyager's plaque is a pretty dumb way to show people our culture and society.

I say we bundle in a video game that shows what daily life was like and throw in a flute or some noise after they beat the game.
posted by mccarty.tim at 12:32 PM on October 7, 2012 [3 favorites]


I say we bundle in a video game that shows what daily life was like and throw in a flute or some noise after they beat the game.

That's been done.
posted by EmpressCallipygos at 1:00 PM on October 7, 2012 [1 favorite]


Last week the middle child was asking about the solar system and a conversation insured in which I explained to the youngest child just what the solar system is. Turns out I gave an incorrect definition, something about 'it's the stuff that goes around the sun'. I had no idea the the correct answer is 'it depends on who you ask'.
posted by TheShadowKnows at 1:02 PM on October 7, 2012 [1 favorite]


That reminds me of how a grad school prof once described teaching 101-level classes: "Just grit your teeth and lie."
posted by mediareport at 1:45 PM on October 7, 2012 [12 favorites]


What, if anything, is Voyager heading towards?
posted by Sebmojo at 2:04 PM on October 7, 2012


It could have at least cleaned up its room before it left the nest.
posted by Brandon Blatcher at 2:19 PM on October 7, 2012


hippybear: If the radiation from the sun isn't the main active force, then it can quite clearly be stated that you've left the system.

I disagree entirely. If you're clear of Earth's magnetic field, you can still be orbiting the Earth. What matters is the Earth's gravitational field, not it's radiation or magnetism. You're still 'near Earth' for as long as Earth's gravity is the dominant force on you. This isn't a huge area, because the Sun quickly overtakes it, but it's way further than the orbit of the Moon. (and if you get close enough to the Moon, suddenly you're 'near the Moon' instead -- its gravity dominates.)

Likewise, you're still in the Solar System until the Sun's gravitational attraction is no longer the strongest force acting on your craft. Eventually, the diffuse gravitational field of the galaxy as a whole will be stronger. At THAT point, and only at that point, have you left the Solar System.
posted by Malor at 2:27 PM on October 7, 2012 [2 favorites]


Argh, wrong "its". and the edit window is closed.
posted by Malor at 2:44 PM on October 7, 2012


> What, if anything, is Voyager heading towards?

from wikipedia:

Voyager 1 is not heading towards any particular star, but in about 40,000 years it will pass within 1.6 light years of the star AC+79 3888, which is at present in the constellation Camelopardalis. That star is generally moving towards our Solar System at about 119 km/s (430,000 km/h; 270,000 mph).

Voyager 2 is heading in the direction of the constellation Telescopium.

though "headed in the direction of a constellation" seems like a strange way to put it, since most constellations only appear in the familiar shapes they take when viewed from earth. but i suppose a point in space is still a point in space.
posted by joeblough at 2:58 PM on October 7, 2012


So it has started on a part of its journey where it's crossing a border and now there's nothing for a long long time. In other words, it's crossing into the west Texas of space.
posted by azpenguin at 3:09 PM on October 7, 2012 [4 favorites]


It isn't crossing into the West Texas of space; it's crossing the street, from one sidewalk to another. Maybe you could say it's crossing into a parking lot.

The city limits are still a ways away, and even the border of the neighbourhood isn't within sight. ( If, that is, we are treating the solar system as a house where things like us can live. )
posted by Fraxas at 4:18 PM on October 7, 2012


That reminds me of how a grad school prof once described teaching 101-level classes: "Just grit your teeth and lie."

I find this mindset maddening. Why is it so wrong to say "the truth about X is complicated" and everyone avoids it?

Why aren't we having more conversations like this?

"Where is the end of the solar system?"
"It's actually kinda complicated. One way to think of it is the furthest distance where anything orbits the sun. I can tell you more about the complicated stuff if you want."
"Yeah that sounds interesting."
(continue with things like solar wind, cosmic rays, magnetic fields)

OR...
"No thanks."
(Let the conversation go... but even then, they get an answer that serves without being misled into thinking it's the only answer available.)

If they say no, you've still told them the truth. Truth is often messy, often complicated. And it doesn't take much longer to just put a qualifier in there.

"Who discovered America?"
"Do you mean the first European to arrive at the Americas after the native people had arrived, or the first human to set foot on the Americas?"

Tell me, what the hell is wrong with that answer? Kids and adults who don't understand that facts live in context with other facts need to learn patience. People who are spoon-fed lies, half-truths, and even true "facts" that are only accurate under certain conditions or by certain definitions often grow up to be closed-minded and feel that ALL answers should be simple.

MOST answers aren't simple. Remind your children when they ask a question....

"What's the tallest building in the world?" (example conversation pre-Burj Khalifa)
"That's actually kind of complicated. Most people measure by the tip of a spire at the top of a building. Some measure by the height of the highest occupied floor. Right now, from the first definition, it's Taipei 101, but more buildings are being constructed right now."

From a very young age kids are fed bullshit or semi-bullshit or even something that has a whiff of bullshit about it, and I hate it. My kids? I knew they wanted something simple because they'd get bored with the full run-down, and that's OK. So I threw in the qualifier, added the "simplest" answer with that qualifier and usually left it at that.

But they never got misled into thinking the answer was always simple or obvious.
posted by chimaera at 5:02 PM on October 7, 2012 [17 favorites]


It's not gone for good. In twenty or thirty years from now we'll have invented some kind of mutant ionic torque drive and taking quick hops out to the solar system will become like driving up to the northwoods to go fishing. People will begin to do it all the time and then someone will come across it floating helplessly somewhere near the comet belts that people use to keep their drinks cool while fishing for space muskie. They'll bring it back like the way someone brings back an old boat anchor and people will marvel at this relic of early space history and it'll be famous again for a while.
posted by lester at 5:51 PM on October 7, 2012 [1 favorite]


Okay, you forced me to research this. "Elvis has left the building" was coined in 1956, when the promoter at an Elvis concert struggled to reassure the fans that, no, Elvis is gone, really gone, and he won't be coming back for an encore. You can all go home; you can't stay here.

And, Star Trek: the Movie not withstanding, I'm pretty sure that Voyager I won't be coming back. Which counts as "left the solar system" in my book. Godspeed you, little toaster.
posted by SPrintF at 5:57 PM on October 7, 2012


"Send more Blind Willie Johnson."
posted by Kinbote at 6:01 PM on October 7, 2012



.



posted by Kronos_to_Earth at 6:47 PM on October 7, 2012 [4 favorites]


I find this mindset maddening. Why is it so wrong to say "the truth about X is complicated" and everyone avoids it?

Well, to be fair, the prof was laughing as he said it, and went on to talk about layers of understanding like layers of an onion, and was all about making that first introduction as useful as possible, acknowledging complexity with first-year students, etc. I think he'd agree with you more than not.

"Grit your teeth and lie" was pretty funny and memorable, though. We all got the point.
posted by mediareport at 7:46 PM on October 7, 2012 [1 favorite]


When discussing the 'edge of the solar system', it strikes me that we're really discussing the edge of the Sun. Obviously gravity and light don't count as being the Sun. It also makes me ponder the notion that we *live* in the Sun.
posted by panaceanot at 8:09 PM on October 7, 2012


It also makes me ponder the notion that we *live* in the Sun.

Whoa. And have you ever, like, really looked at your hands, man?

(sorry, I couldn't resist)
posted by Greg_Ace at 8:57 PM on October 7, 2012


SEND MORE CHUCK BERRY
posted by not_on_display at 9:46 PM on October 7, 2012 [2 favorites]


Finally. I didn't want to say anything while it was here but doesn't anyone else think Voyager is a little stuck up?
posted by Bonzai at 10:04 PM on October 7, 2012 [1 favorite]


It does seem a bit...distant.
posted by Greg_Ace at 10:13 PM on October 7, 2012


Woah. My hands are fucking INCREDIBLE.
posted by panaceanot at 10:41 PM on October 7, 2012 [1 favorite]


But you can't really blame it for being a space cadet.
posted by porpoise at 10:45 PM on October 7, 2012


If a bunch of nitwits like us can send something beeping out of the solar system it is not good that we haven't found anyone elses calling card.

Voyager 1 is not heading towards any particular star, but in about 40,000 years it will pass within 1.6 light years of the star AC+79 3888

Yeah if you want to consider 1.6 light years "buzzing the tower" there could be alien spacecraft cruising by outside constantly and we'd never have any idea. My (baseless) hunch is that there are countless messages in bottles like ours out there, but the "body of water" in question is just impossibly, mind-breakingly big.
posted by chaff at 12:33 AM on October 8, 2012


In fact I seem to remember it's something of a sci-fi trope to realize that launching out objects is a wash, and that you're better off doing something like making a sun go nova in some weird artificial way that couldn't be natural. Don't remember any titles but I know I've read something like that. Of course, the people viewing your message might not see it for hundreds of millions of years, by which time you're probably extinct, but hey at least you got to blow up a star.
posted by chaff at 12:46 AM on October 8, 2012 [1 favorite]


Why is it so wrong to say "the truth about X is complicated"

Because if you want to explain, say, the chemical bond between sodium and chlorine in NaCl to a high-school student, you'd have to stop and do that "now the truth here is actually much more complicated" dance for just about every word you use.
posted by straight at 12:55 AM on October 8, 2012 [1 favorite]


Chimaera, I'm still pissed that its only been the past 5 years or so I realized what I was taught about gravity was a damn dirty lie. Most likely because it was thought teaching highschoolers Neuton's laws of physics is easier than einstein's space time. Most of my adult life, wrong. I suppose not being a physist it didn't really matter, but damn if I didn't feel betrayed.

. . . So, back to the subject at hand, how much effort would it take to launch a smartphone sized/weight into space? Possible crowd sourced space probe to follow in voyagers path? I smell a kickstarter!
posted by [insert clever name here] at 1:00 AM on October 8, 2012


Amazing that a machine built more than 35 years ago is still running and sending back data.

I will actually be more amazed if anything we send into space now is still running in 35 years. There's often a reliability cost to complexity.
posted by flabdablet at 2:27 AM on October 8, 2012 [1 favorite]


It's the point where the radiation from the sun is no longer the dominant force and the general cruft of the neutral universe takes over

The Sun's gravity field holds in a large number of objects much farther away than the heliosphere. The only reason Voyager 1 (along with Pioneers 10 & 11, Voyager 2, and New Horizons) is leaving is that we threw them really, really, hard, and then whipped them around a gas giant or two for an extra velocity boost.

Even as far away as Voyager 1 is, the Sun is the most prominent object in the sky, shining about magnitude -16.
posted by eriko at 6:03 AM on October 8, 2012


+---------------------+
| NEXT GAS |
| 9.3 TRILLION MILES |
+---------------------+

The restrooms in Camelopardalis are totally rad.
posted by KevinSkomsvold at 7:11 AM on October 8, 2012 [1 favorite]


What I find more incredible ... is that we are still able to hear its feeble radio signal and collect data from it across these incredibly fast distances and against all the background radiation.

That's impressive, isn't it? Only the largest of the Deep Space Network dishes (230 feet in diameter!) can communicate with the Voyagers. Apparently sometimes engineers will array groups of dish antennas (e.g., the Deep Space Network Goldstone dishes arrayed with the Very Large Array dishes) to communicate. And on top of that, they super-cool the receivers to near absolute zero to reduce interference. It makes me think about how tricky it would be to talk to a spacecraft further out than the Voyagers...
posted by b_alex_a at 8:52 AM on October 8, 2012 [1 favorite]


Let us celebrate this momentous occasion with ice cream.
posted by homunculus at 10:36 AM on October 8, 2012


So, back to the subject at hand, how much effort would it take to launch a smartphone sized/weight into space?

Cheap to launch. Lasts 18 hours.
posted by ChurchHatesTucker at 10:49 AM on October 8, 2012


Egg Shen: That there are farther-out objects gravitationally bound to the sun doesn't seem relevant when Voyager itself is not.
Technically, Voyager has not been bound to the sun for many years (since it last accelerated under its own power), so that criterion is meaningless.
posted by IAmBroom at 1:01 PM on October 8, 2012


not sure why you can't define the boundary of the solar system gravitationally, regardless of what voyager is doing. but as countless others upthread have pointed out, defining where the solar system ends is somewhat arbitrary and perhaps multiple definitions are just fine, depending on the purpose.
posted by joeblough at 1:53 PM on October 8, 2012 [1 favorite]


All mass in the universe is gravitationally bound; gravity doesn't just stop. The gravity boundary doesn't make a lot of sense.
posted by spaltavian at 4:39 PM on October 8, 2012


No one means what you're taking them to mean by "gravitationally bound", spaltavian. They mean that the gravity of the sun is not sufficient in and of itself to ever bring Voyager 1 back (or keep it in orbit).
posted by Flunkie at 5:37 PM on October 8, 2012 [3 favorites]


not sure why you can't define the boundary of the solar system gravitationally

Well you could try, but the boundary would need to be at least six-dimensional (three of position, three of velocity) even if purely gravitational interactions with objects inside the boundary were the only defining criterion. And as others have pointed out in slightly different language, Voyager has been outside any such boundary since running out of fuel.
posted by flabdablet at 6:10 PM on October 8, 2012


No one means what you're taking them to mean by "gravitationally bound", spaltavian. They mean that the gravity of the sun is not sufficient in and of itself to ever bring Voyager 1 back


That is exactly what I mean though. There is no such thing as absolute distance that the sun couldn't recapture it; it's just a question of what else is out there. But stars are in constant relative motion; so the "size" will always be changing. And of course, distance has nothing to do with it; escape velocity was achieved by Voyager when it was still within the orbits of some planets.
posted by spaltavian at 6:23 PM on October 8, 2012


Of course there's no absolute distance that the sun couldn't recapture it. There are, however, combinations of distance and velocity for which the sun couldn't recapture it by its own means (and incidentally, yes, distance absolutely has something to do with it; escape velocity is smaller as you are farther). That's what people are meaning, and I seriously doubt that there's anyone who's laboring under the confusion that you seem to think everyone is laboring under.
posted by Flunkie at 6:34 PM on October 8, 2012 [1 favorite]


Maybe it would help to ask a slightly different question, "when have you left Earth?"

You could posit varous points in the atmosphere -- and the atmosphere goes WAY out, the ISS is sailing through it in a noticeable way. But obviously there are a lot of (mostly human placed) whirly bits out there that are clearly coming home one day which are far outside the remotest reaches of the atmosphere.

You could say the Earth's magnetosphere and Van Allen belts (which are why the Earth, unlike Mars, still has an atmosphere); these go out much further and take sensitive instruments to detect. This is probably closer to the standard being applied to the Voyager data.

But then, the Moon is much further out than that, and it's pretty tightly coupled to the Earth; from Mars, a lot of observers would call our system a double planet. This is a lot like the situation with the really far-orbiting cometoids. Except they actually stand a better chance of being stolen by a chance encounter with another star than Luna does being stolen by a chance encounter with another planet.

The Apollo planners considered their astronauts to have left Earth when the Moon's gravitational attraction was stronger than the Earth's. They were still solidly within the Earth-Luna system though, although if they hadn't aimed for the moon they could have left it for independent Solar orbit.

There's also, in Earth's case, the weird situation with at least one asteroid that leads Earth in its orbit until it nearly catches up, is deflected a bit into a lagging orbit, then lags until Earth catches up to it and it gets deflected again into a leading orbit, lather rinse repeat. According to current definition this thing is part of the Earth *cough* system even though it's occasionally 2 AU away on the other side of the Sun. It seems kind of wacky to argue that something 2 AU away is "in the Earth system" even if it is coupled to Earth's solar orbit by some weird dynamic resonance.

Like the Earth's Van Allen belts and the magnetosphere, though, which are very real things that keep us alive, the heliosphere is a very real and measurable thing. There might be orbiting wanderers that pass through it from time to time but it's an important division between that which is Sol and that which is not-Sol. And it's actually a more definite division than most other candidates.
posted by localroger at 6:57 PM on October 8, 2012 [2 favorites]


So, back to the subject at hand, how much effort would it take to launch a smartphone sized/weight into space? Possible crowd sourced space probe to follow in voyagers path?

Cubesats: $40k, for a 10cm cube. Recently on MeFi.

Groups like AMSAT have been putting tiny amateur satellites into orbit piggybacked on commercial/military launches and such since the 1960s(!). You can get a much cheaper launch if you don't need to end up in an especially predictable orbit.

I don't think any of the amateur rocketry folks have reached orbital velocities.

These are all in fairly low Earth orbit though and to follow Voyager you'd need to somehow reach solar escape velocity. You don't have much mass to spare for reaction, so some sort of solar sail / magsail seems like the only way to go.
posted by hattifattener at 11:49 PM on October 8, 2012


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