
Voyager 1 has been traveling for about a year through plasma between stars - ComputerGuru
http://www.nasa.gov/mission_pages/voyager/voyager20130912.html
======
hypersoar
From "The West Wing", around one of the last times Voyager left the solar
system:

 _" Voyager, in case it's ever encountered by extra-terrestrials, is carrying
photos of life on Earth, greetings in 55 languages and a collection of music
from Gregorian chants to Chuck Berry. Including "Dark Was The Night, Cold Was
The Ground" by '20s bluesman Blind Willie Johnson, whose stepmother blinded
him when he was seven by throwing lye in is his eyes after his father had beat
her for being with another man. He died, penniless, of pneumonia after
sleeping bundled in wet newspapers in the ruins of his house that burned down.
But his music just left the solar system."_

It's pretty amazing how far we've extended our reach, if not our grasp.

~~~
hannibal5
the song:
[https://www.youtube.com/watch?v=BNj2BXW852g](https://www.youtube.com/watch?v=BNj2BXW852g)

~~~
wlll
The song might have left the solar system, but it's not arrived in the UK yet:

"This video contains content from PEDL, SME, PRS CS, AdShare MG for a Third
Party and Warner Chappell, one or more of whom have blocked it in your country
on copyright grounds."

~~~
wslh
Sadly the Voyager doesn't run uTorrent...

~~~
brokenparser
But I'm pretty sure it runs some kind of transmission.

------
stephenhuey
Several commenters are joking about how many times they've heard this before,
but NASA goes into great detail about why it was so difficult to measure and
what new information helped them decide for sure. Here's a small excerpt:

"The particular oscillations meant the spacecraft was bathed in plasma more
than 40 times denser than what they had encountered in the outer layer of the
heliosphere. Density of this sort is to be expected in interstellar space."

Read their account of how an "unexpected gift from the sun" helped them. It's
not long and quite fascinating, and some little tidbits like this are pretty
intriguing to me:

"By the time the signals get to Earth, they are a fraction of a billion-
billionth of a watt."

~~~
DanBC
> "By the time the signals get to Earth, they are a fraction of a billion-
> billionth of a watt."

Check my math but one billionth of a Watt is 1 nW. So one billion-billionth of
a Watt is 1 atto Watt?

~~~
HowardMei
It's a shame that Voyager doesn't carry some tiny nuke bombs to mark its
positions. The SNR at a billion-billionth of a watt level is terrible.

~~~
thelambentonion
An excerpt from a course I recently attended:
[http://i.imgur.com/6VW4X3o.png](http://i.imgur.com/6VW4X3o.png)

The noise floor of the Goldstone Observatory is truly incredible.

------
kens
I agree with everyone who is tired of the "Voyager has left the solar system"
PR game, but I'll point out that the latest announcement is data confirming
last year's Aug. 25, 2012 exit date, not a new exit. That is, they have new
data showing that the previous departure was "real".

------
WestCoastJustin
If the universe is continually expanding, does that mean we are trying to hit
a moving target? Probably sounds like a stupid question, but I honestly want
to know.

There was a xkcd comic about this @
[http://xkcd.com/1189/](http://xkcd.com/1189/)

~~~
mturmon
The Hubble constant is 67.8 (km/s)/Mpc. That means that something one Mega-
parsec (Mpc) away will appear to recede at about 70 km/s. Our galaxy is about
35 kpc across.

Voyager is currently 0.0006 parsecs from Earth, moving at 17 km/s.

Given this distance, we find that the cosmological effect alters the apparent
velocity of Voyager by 4.2x10^-8 km/s. This is only 1 part in 4x10^8, which is
probably too small to measure.

There may be general-relativistic corrections to the spacecraft clocks,
however, and computation of its trajectory may involve general-relativistic
dynamics. So some of the often-ignorable effects probably do add up.

Of course, the surrounding volume is also expanding with the same rate, so
from that point of view, there is no effect.

~~~
privong
The expansion of the Universe is irrelevant in this case. Our galaxy is
gravitationally bound, so things (stars, planets, etc) within it do not follow
Hubble's law. So there will be no modification to Voyager's distance from
earth as a result of the Universe's expansion.

Even nearby galaxies don't obey Hubble's law. Andromeda, for example, is
moving towards us, despite the overall expansion of the universe. In this
case, it is due to the gravitational attraction between it and our galaxy.

~~~
mturmon
You are offering a more sophisticated take on the matter. At non-cosmological
scales, metric expansion (i.e., the Hubble law) is not occurring because of
bulk gravitational attraction.

The arithmetic I did is a tool illustrating the scale that is needed to make
metric expansion operative. The arithmetic has the advantage of giving a
quantitative idea how far away Earth-Voyager is from the necessary scale.

~~~
privong
> The arithmetic I did is a tool illustrating the scale that is needed to make
> metric expansion operative.

You might revisit the wording then. As it's written it implies that with
arbitrarily increased measurement precision, we could measure an effect of the
Hubble Flow on Voyager's movement. But even with arbitrary precision we'd
never measure an effect from the Hubble Flow on Voyager's motion because the
expansion of the Universe isn't contributing to the relative motion between
Earth and Voyager.

------
Miyamoto
> _Stone discussed with the Voyager science group whether they thought Voyager
> 1 had crossed the heliopause. What should they call the region were Voyager
> 1 is?

> "In the end, there was general agreement that Voyager 1 was indeed outside
> in interstellar space," Stone said. "But that location comes with some
> disclaimers - we're in a mixed, transitional region of interstellar space.
> We don't know when we'll reach interstellar space free from the influence of
> our solar bubble."

> So, would the team say Voyager 1 has left the solar system? Not exactly -
> and that's part of the confusion. Since the 1960s, most scientists have
> defined our solar system as going out to the Oort Cloud, where the comets
> that swing by our sun on long timescales originate. That area is where the
> gravity of other stars begins to dominate that of the sun. It will take
> about 300 years for Voyager 1 to reach the inner edge of the Oort Cloud and
> possibly about 30,000 years to fly beyond it. Informally, of course, "solar
> system" typically means the planetary neighborhood around our sun. Because
> of this ambiguity, the Voyager team has lately favored talking about
> interstellar space, which is specifically the space between each star's
> realm of plasma influence._

[http://www.jpl.nasa.gov/news/news.php?release=2013-278](http://www.jpl.nasa.gov/news/news.php?release=2013-278)

I tend to agree with their rationale, but they may just be pressed with time
(remaining power on Voyager 1) and want conclusion. They can't wait 300 -
30,000 years.

------
achairapart
For the series _something went wrong_ : The CPUs inside this spacecraft run at
just 0.25Mhz.

"The Voyager spacecraft computers are interrupt driven computer, similar to
processors used in general purpose computers with a few special instructions
for increased efficiency. The programming is a form of assembly language."

"The master clock runs at 4 MHz but the CPU’s clock runs at only 250 KHz. A
typical instruction takes 80 microseconds, that is about 8,000 instructions
per second. To put this in perspective, a 2013 top-of-the-line smartphone runs
at 1.5 GHz with four or more processors yielding over 14 billion instructions
per second."

Source:
[http://voyager.jpl.nasa.gov/faq.html](http://voyager.jpl.nasa.gov/faq.html)

------
chacham15
Is it just me, or is anyone else fascinated by the idea that we receive data
from a device that is 12 billion miles away at a rate of 20 bytes a second?
How do they deal with the problem that there is most likely to be a lot of
interference in the form of other planets, magnetic waves, solar flares,
random gamma rays, etc?

~~~
CodeCube
It's not just you ... it is fascinating. I would love to have a good chat over
some beers or coffee with some of the engineers and scientists that built this
:)

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jessaustin
A more interesting event will be when crewed spacecraft "pass" the Voyagers.
Betting this won't happen is basically betting that humanity will destroy
itself.

~~~
grecy
I read a great book a long time ago.. wish I could remember the name.

Basically, sometime in the future, Earth is dying, so everyone has to leave to
some faraway planet within 100 years.

The first intrepid explorers leave at T-100 years, expecting to be the first
to arrive. A few years later a new craft leaves that can travel faster and
will get there sooner. This goes on and on until it comes down to a betting
game of how late can you wait until leaving, while still being the first to
arrive (and thus claim ownership/leadership, etc.), with people coming up with
all kinds of hair-brained schemes on the best time to actual leave.

IIRC, it kind of turned a little into Hitchhikers Guide kind of ridiculous
near the end.

~~~
jessaustin
IIRC there was something in _Hyperion_ about this, but it wasn't a focus, just
some back-story on why Martin Silenus was brain-damaged for some time after
his emigration from Old Earth. (Bad cryo on a slow-ass spaceship.)

Probably not what you're thinking of... It sounds like something Asimov would
have written but nothing comes to mind.

~~~
farnsworth
This is the one I was thinking of. I completely forgot about that book, thanks
for the reminder.

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Abundnce10
_" After the data are transmitted to JPL and processed by the science teams,
Voyager data are made publicly available."_

Where can I find Voyager data?

~~~
csixty4
[http://voyager.jpl.nasa.gov/science/Voyager_Science_Data.htm...](http://voyager.jpl.nasa.gov/science/Voyager_Science_Data.html)

------
farresito
A question for the physicists or people that know about the subject: does
plasma affect circuits? I read somewhere that alpha particles do affect them.
I'm just curious. It might well be a stupid question. Pardon for my ignorance.

~~~
cothomps
There are two things to keep in mind:

1) The electronics on board Voyager (and all spacecraft we've launched) are
pretty well shielded.

2) The density of the plasma in interplanetary (now interstellar) space is
very, very low. What Voyager is measuring is not the direct particles, but the
oscillations of them. (Radio waves)

[http://en.wikipedia.org/wiki/Plasma_receiver](http://en.wikipedia.org/wiki/Plasma_receiver)

Don Gurnett @ the U. of Iowa has been a part of many of these missions -
plasma receivers have been on nearly every major mission since Voyager. (Esp.
Galileo to Jupiter and Cassini to Saturn.)

Here's a link to the research group at the U. of Iowa (the same group that
published today's paper in Science) - there are some good introductory
articles on the instruments and the physics behind them:

[http://www-pw.physics.uiowa.edu](http://www-pw.physics.uiowa.edu)

~~~
InclinedPlane
To expand on #2, the environment around Voyager 1 is significantly lower
pressure and density than the most extreme ultra-high-vacuum conditions humans
have ever managed to create on Earth.

------
auton1
Ahem... [http://xkcd.com/1189/](http://xkcd.com/1189/)

~~~
tootie
I think Voyager may be approaching the Phantom Zone.

------
sgustard
“These younger engineers can write a lot of sloppy code, and it doesn’t
matter, but here, with very limited capacity, you have to be extremely precise
and have a real strategy,” she said.

[http://www.nytimes.com/2013/09/13/science/in-a-
breathtaking-...](http://www.nytimes.com/2013/09/13/science/in-a-breathtaking-
first-nasa-craft-exits-the-solar-system.html)

------
noselasd
Be sure to check out the Reddit AMA yesterday;
[http://www.reddit.com/r/IAmA/comments/1m9wke/were_scientists...](http://www.reddit.com/r/IAmA/comments/1m9wke/were_scientists_and_engineers_on_nasas_voyager/)

------
dombili
Must read piece on the matter: [http://www.bbc.co.uk/news/science-
environment-24072587](http://www.bbc.co.uk/news/science-environment-24072587)

------
Coincoin
Nice! This time it's real because we have an artist's depiction of voyager
going from non-ionized almost void to ionized almost void.

------
martinkallstrom
Third time's a charm

------
apierre
What kind of software has Voyager inside? I am amazed it has been running for
36 years. Updates at 20 byte a second must be fun:-)

------
skidoo
And the techie who lost his car-keys 36 years ago is still really kicking
himself.

~~~
arunabha
Huh ? context please.

~~~
dclowd9901
I think the implication is that he left them in the voyager.

------
Pxtl
Again?

~~~
breadbox
In general you're right to mistrust the oft-repeated headline. But this is
actually a big deal. Voyager I really is exploring a new part of space for the
first time.

It's also worth noting that Voyager I entered interstellar space well over a
year ago, but that only now have we been able to confirm that fact. So if it
seems like this has been repeated a lot lately, it's because the scientists
have been sifting this data for a long time before they could be sure. (Again,
this is uncharted territory for the human race.)

------
repdetec
Pics or it didn't happen.

------
speeder
They say that so much, that I will consider news when they say Voyager 1 is in
another star (or in another... whatever it finds along the way!)

THEN I will consider it news...

Even because some scientists consider even the oort cloud (that is hell far)
still part of solar system anyway.

~~~
testing12341234
It's likely you would be dead before then. Voyager 1 after 36 years is about
127 AU away. The oort cloud is believed to be at least 50,000 AU away [0]. So
you'll have to wait about another 14,000 years.

[0] -
[http://en.wikipedia.org/wiki/Oort_cloud](http://en.wikipedia.org/wiki/Oort_cloud)

~~~
jlgreco
And Voyager 1 isn't expected to pass the star AC+79 3888 (in the 'Little
Dipper') until 40,272 AD.

[http://voyager.jpl.nasa.gov/faq.html](http://voyager.jpl.nasa.gov/faq.html)

~~~
T-hawk
"Pass" being a pretty generous term, coming within 1.7 light-years, or over
500 times farther than its lifetime distance from Earth/Sol to today. It's
like driving from New York to San Francisco and calling some spot in Kansas
"passing the moon".

All of the Solar System outbound spacecraft aren't expected to pass within,
say, the planetary disc range of any known stars at any calculable future
time. Space is really freakin empty.

------
sami36
No kidding, That's about the 6th time I've read about it these last two years.
WHY doesn't NASA begin by establishing WHAT is it exactly that makes a solar
system official "boundary" before producing press releases every time they
find something interesting in the readings sent to them by Voyager.

ADDENDUM : Ahem, Thanks for the downvotes, but the inner workings of space
discovery are not the subject of my comment. As an engineer, I'm more than
mindful of the back & forth & general messiness of discovery, peer-reviews,
control groups, & the like. I'm talking about press releases & headlines
targeted towards the GENERAL PUBLIC. A public that has a lot less of an
appetite, patience or time to follow NASA's inner deliberations or the
intricacies of the scientific method. The fact that this is the 5th or sixth
time that they've heard that "Voyager has left the solar system" might leave
them a little bit confused.

~~~
dragonwriter
> WHY doesn't NASA begin by establishing WHAT is it exactly that makes a solar
> system official "boundary" before producing press releases every time they
> find something interesting in the readings sent to them by Voyager.

Because _discovering new things_ is actually more important than drawing
arbitrary lines.

~~~
sami36
the inner workings of space discovery are not the subject being discussed
here. As an engineer, I'm more than mindful of the back & forth & general
messiness of discovery, peer-reviews, control groups, & the like. I'm talking
about press releases & headlines targeted towards the GENERAL PUBLIC. A public
that has a lot less of an appetite, patience or time to follow NASA's inner
deliberations. The fact that this is the 5th or sixth time that they've heard
that "Voyager has left the solar system" might leave them a little bit
confused.

~~~
jlgreco
The general public is footing the bill, there is nothing wrong with giving the
general public some periodic status updates. This could really only get
confusing if you read no further than the headlines.

~~~
sami36
"...if you read no further than the headlines."

That's the definition of how the general public interacts with a piece of
news.

~~~
jlgreco
People who read no further than headlines will have trouble regardless. The
solution to that is not _" release fewer press releases so that people have
fewer opportunities to be confused"_.

~~~
sami36
Now, you're just being argumentative for argumentation sake. I'm done

~~~
taproot
Gen pop don't get smarter if you don't make them think. Confusion can be
useful and in this case likely a good bit of medicine. Grade school education
level of understanding on anything is pretty useless and implying that they
cant do better insults pretty much everyone. Hence the d/v's.

