Voyager 1 spacecraft reaches interstellar space, study confirms

Sep 12, 2013
Voyager 1 spacecraft reaches interstellar space
An artist's concept shows the Voyager spacecraft traveling through space against a field of stars. Credit: NASA/JPL-Caltech.

University of Iowa space physicist Don Gurnett says there is solid evidence that NASA's Voyager 1 spacecraft has become the first manmade object to reach interstellar space, more than 11 billion miles distant and 36 years after it was launched.

The finding is reported in a paper published in the Sept. 12 online issue of the journal Science.

"On April 9, the Voyager 1 Plasma Wave instrument, built at the UI in the mid-1970s, began detecting locally generated waves, called electron plasma oscillations, at a frequency that corresponds to an about 40 times greater than the density inside the —the region of the sun's influence," says Gurnett. "The increased electron density is very close to the value scientists expected to find in the .

"This is the first solid evidence that Voyager 1 has crossed the heliopause, the boundary between the heliosphere, and ," says Gurnett, principal investigator for the instrument.

For several months, the relative position of Voyager 1 has stirred something of a scientific debate because there remains some lingering evidence of the nearby heliosphere beyond the heliopause.

Even though Voyager 1 has passed into interstellar space, it does not mean that its journey is over, says Bill Kurth, UI research scientist and co-author of the Science paper.

This is an artist's impression of Voyager 1's position on the sky when observed by the Very Long Baseline Array (VLBA) on Feb. 21, 2013, at which point -- according to NASA's Jet Propulsion Laboratory -- Voyager was already outside of our solar system. The actual image from the data (enlarged section) is 0.5 arcseconds across. The radio signal as shown is a mere 1 milliarcsecond across. Credit: Alexandra Angelich, NRAO/AUI/NSF.

"Now that we're on the outside, we are learning that interstellar space isn't a bland region," Kurth says. "Rather, there are variations in some of Voyager's measurements that may be due to the nearby presence of the heliosphere. So, our attention is turning from crossing the boundary to understanding what is going on outside," he says.

At age 36, Voyager 1 is the most distant human-made object at more than 11.6 billion miles from the sun, or about 125 astronomical units.

"At that distance it takes more than 17 hours for a to travel from the spacecraft to one of NASA's Deep Space Network antennas. The signal strength is so incredibly weak that it takes both a 230-foot and a 110-foot-diameter antenna to receive our highest resolution data," Gurnett says.

Launched Sept. 5, 1977, Voyager 1 completed flybys of both Jupiter and Saturn and is currently moving outward from the sun at about 3.5 AU per year. A sister spacecraft, Voyager 2 was launched Aug. 20, 1977, on a flight path that took it to encounters with Jupiter, Saturn, Uranus, and Neptune. At present, Voyager 2 is still inside the heliosphere about 103 AU from the sun and traveling outward at about 3.3 AU per year.

Explore further: Orion on track at T MINUS 1 Week to first blastoff

More information: The sounds of the electron plasma oscillations heralding Voyager's entry into interstellar space and other sounds of space can be heard by visiting Gurnett's website at: www-pw.physics.uiowa.edu/space-audio/

Paper: "In Situ Observations of Interstellar Plasma With Voyager 1," by D.A. Gurnett et al Science, 2013.

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no fate
4.6 / 5 (9) Sep 12, 2013
Reminds me of the childhood book "The little engine that could".
axemaster
5 / 5 (17) Sep 12, 2013
This is a huge event in human history. For the first time ever, humans have sent something beyond the edge of our solar system. We have progressed from interplanetary to interstellar flight!
El_Nose
5 / 5 (6) Sep 12, 2013
@axe

technically correct -- even if still travelling at interplanetary speeds
Solon
1 / 5 (10) Sep 12, 2013
I thought the Solar system went out as far as the Oort cloud, which would mean there is still a long way to go to reach interstellar space.
Anda
5 / 5 (3) Sep 12, 2013
This is a huge event in human history. For the first time ever, humans have sent something beyond the edge of our solar system. We have progressed from interplanetary to interstellar flight!

That's awesome. Nothing to add to axemaster's comment...
rug
1.6 / 5 (13) Sep 12, 2013
The oort cloud has already been passed up. This is the same craft that gave us images of Pluto. It's been out that way for a really long time.
DistortedSignature
5 / 5 (1) Sep 12, 2013
@Solon

I wonder if that's a misnomer where they define outside of a solar system things that isn't in the heliosphere of a star(s). Are there systems with planets that orbit outside of their star's heliosphere? I believe Eris has a max of 97 AU distance from the sun.

http://upload.wik....svg.png
spencerpencer
2.6 / 5 (5) Sep 12, 2013
Is it for really reals this time or are we getting another press release saying the exact same thing 3 days from now YET AGAIN??
MrVibrating
3.5 / 5 (11) Sep 12, 2013
17 Light-hours away... just... wow..
RealScience
4 / 5 (8) Sep 12, 2013
A great achievement for humanity!

@Distorted - Yes, there are many definitions of the limit of the solar system This particular one is based on the solar wind and solar magnetic field. The gravitational sphere of influence is far larger (~ 1 light year).

@rug - no. Voyager 1 has not yet passed the Oort cloud, which is hypothesized to be light-months from the sun rather than mere light-hours. You are probably thinking of the Kuiper Belt at roughly 30 to 50 AU (4 to 7 light hours), which at 17 light hours v'ger has indeed passed.
rug
2.1 / 5 (14) Sep 12, 2013
ah, yeah, my goof
radek
1.8 / 5 (14) Sep 12, 2013
The oort cloud has already been passed up. This is the same craft that gave us images of Pluto. It's been out that way for a really long time.


You`re wrong. Voyager passed Kuiper belt
Q-Star
3.2 / 5 (9) Sep 12, 2013
ah, yeah, my goof


Everybody goofs,,,, not a biggie,,,
Humpty
1.3 / 5 (15) Sep 12, 2013
Hmmmmm are they sure that they are sure this time? Or will they be sure next time? Or the time after that? Or will the definitions change again, perhaps several more times, and then there will be endless amounts of speculation and hypothesis and endless daily press releases for each incremental guessing game "proof" for months and years on end?

To me I don't particularly give a shit.....

"It's just gone out in space and it's wayyyyyyy out in space.

And when it's gone out in space it is gone out in space.

And when it's wayyyyyyyyy out in space, it's wayyyyyyy out in space.

And when it's gone out in space and when it's wayyyyyyy out in space, there ain't no way it's ever coming back."

radek
1.7 / 5 (14) Sep 12, 2013
Can anybody explain why electron density is greater outside Solar System?
Q-Star
3 / 5 (6) Sep 12, 2013
Or will the definitions change again, perhaps several more times, and then there will be endless amounts of speculation and hypothesis and endless daily press releases for each incremental guessing game "proof" for months and years on end?


I suppose if all depends on your world view. It's brand new science. This is the VERY FIRST attempt in all of history to send something out of the solar system. They are searching for something that has never been seen before,

I think it speaks volumes of the engineers who built this thing, they deserve big kudos for making it possible for the science guys to DISCOVER exactly where this place ya are not interested in is.

And when it's gone out in space and when it's wayyyyyyy out in space, there ain't no way it's ever coming back."


Why would we want it to come back? It would be useless to us here.
Q-Star
3.4 / 5 (10) Sep 12, 2013
Can anybody explain why electron density is greater outside Solar System?


Electron density falls off as one approaches the heliosphere, once crossing it, the density increases (as compared to the inner boundary of the heliosphere). The density is not really greater than that in the solar system on average, just greater than the area just inside the boundary.
radek
1.8 / 5 (12) Sep 12, 2013
Can anybody explain why electron density is greater outside Solar System?


Electron density falls off as one approaches the heliosphere, once crossing it, the density increases (as compared to the inner boundary of the heliosphere). The density is not really greater than that in the solar system on average, just greater than the area just inside the boundary.


article states it is significantly greater "(..)about 40 times greater than the density inside the heliosphere(..)"

TheGhostofOtto1923
1.6 / 5 (7) Sep 12, 2013
Since we already know V-ger's location, why not use Hubble or Spitzer to take some images. Or is it just too small?
No it is still the same size pussytard it is just too far away.

And we already have many pictures of it. Here are some for you.
http://www.startr...cle/vger
Q-Star
3.4 / 5 (5) Sep 12, 2013
Can anybody explain why electron density is greater outside Solar System?


Electron density falls off as one approaches the heliosphere, once crossing it, the density increases (as compared to the inner boundary of the heliosphere). The density is not really greater than that in the solar system on average, just greater than the area just inside the boundary.


article states it is significantly greater "(..)about 40 times greater than the density inside the heliosphere(..)"



That is only at boundary,,, the density decreases as you approach the heliosphere, starting from sun going out, very gradually,, when ya cross the boundary it suddenly increases, they have been predicting just this sudden increase. It has to do with the magnetic fields inside of the heliosphere. It may be 40 times greater at the boundary, but it's orders of magnitude less than anything inside the orbit of Neptune or Pluto.
Torbjorn_Larsson_OM
4.2 / 5 (5) Sep 12, 2013
It is historical. The reach in time, space and technology. But also the science that signaled the first step outside.

The observations are very neat. Besides this large coronal mass ejection passing, which enabled the measurement, there were two previous ones at smaller electron densities.
Extrapolating backwards, they meet the date of the drop in solar wind and increase in cosmic rays. And the current electron density is what is measured for the interstellar medium (ISM) by other means.

Meanwhile we have the theoretical paper that claims the small swing in magnetic field direction instead of the large swing earlier expected is consistent with entering the ISM.
Torbjorn_Larsson_OM
3.7 / 5 (6) Sep 12, 2013
As for images, I like the one taken in the radio band with the Deep Space Network (I think) on the accompanying NASA video. It's a small radio luminous speck when it transmits.

Optical images are impossible of course, too small angular width. I'm reminded of the nincompoop moon landing denialists that wants to do the same with same size Apollo landers on the _Moon_ with Hubble. Somehow they can't calculate or even imagine the angular width, which shows you can't resolve a football field even.

@Solon: There is no definite boundary of the solar system. What has happened here is that the craft has left the solar influence on EM fields and so particle winds. By definition it has hence entered the interstellar plasma that occupies the distances between stellar influences.

On the other hand the craft hasn't left the solar influence on gravity fields. The ocean ships of the Oort cloud sails beyond the solar shores, so to say.
jmlvu
2.1 / 5 (13) Sep 12, 2013
This means that the prime directive no longer applies and the United Federation of Planets can now contact earth. I'm going to get my flashlight and go await thier arrival.
PoppaJ
1 / 5 (8) Sep 12, 2013
They will now come.
BAKOON
1.6 / 5 (7) Sep 13, 2013
Idiot-shit, please don't stink up this topic with your evil bullshit. This is too important.
xEnomania
1 / 5 (4) Sep 13, 2013
what is this 10th time they've announced this?! Please, check your numbers, NASA.
El_Nose
4.2 / 5 (5) Sep 13, 2013
Just a FYI

As with a lot of things in astronomy ...

the Oort Cloud is hypothetical. It is not confirmed, because the object in it would be really cold, hopefully the JWST will image a lot of them. But we know of very few object in the region of the hypothetical Orrt cloud.

For the uninitiated the Oort cloud is supposed to expected to about 50,000 - 100,000 AU or 1 - 1.8 lyr from Sol. It is expected to contain trillions of comets and asteroids. We have seen a few object in this region, i think, please fact check that.
El_Nose
3.4 / 5 (5) Sep 13, 2013
@Qstar

I saw another article stating the increase was 2 orders of magnitude or 100x increase.
Humpty
1 / 5 (10) Sep 14, 2013
I sent some hydrogen out of the universe 50 years ago - it only took 8 hours to do it as well.
RealScience
3.4 / 5 (5) Sep 14, 2013
the Oort Cloud is hypothetical. It is not confirmed, because the object in it would be really cold, hopefully the JWST will image a lot of them. But we know of very few object in the region of the hypothetical Orrt cloud.


@El_Nose - exactly - the Oort cloud is hypothesized rather than observed directly. What we have observed is long-period comets whose aphelia match the hypothesized Oort cloud, providing indirect evidence.
vidyunmaya
1 / 5 (10) Sep 16, 2013
Sub: Importance of the region-Space cosmology vedas interlinks
The Oort cloud is thought to occupy a vast space from somewhere between 2,000 and 5,000 AU (0.03 and 0.08 ly)[12] to as far as 50,000 AU (0.79 ly)[3] from the Sun. Some estimates
place the outer edge at between 100,000 and 200,000 AU (1.58 and 3.16 ly).[12] The region can be subdivided into a spherical outer Oort cloud of 20,000–50,000 AU (0.32–0.79 ly), and a
doughnut-shaped inner Oort cloud of 2,000–20,000 AU (0.03–0.32 ly).
triplehelix
1 / 5 (9) Sep 16, 2013
"The signal strength is so incredibly weak that it takes both a 230-foot and a 110-foot-diameter antenna to receive our highest resolution data," Gurnett says."

So we have two giant antennas that can *just about* compute the signal from something we have a very direct idea of it's location. It is merely 17 light hours away.

No wonder we're not finding radio waves from other intelligent species if we can barely get something 17 light hours away and homing directly in on it's position. Essentially any intelligent life using radiowave signalling like us even a few light years away the signal will be essentially non existent, and we don't have direct coordinates to home in on it anyway.

Surely to be classed as interstellar we have to go to another star?
El_Nose
1 / 5 (1) Sep 16, 2013
@triple

the voyager space craft if it had an antennae to say watch tv could do so that far out as the signal loss would not be too bad, though it might be a little staticy. Voyager just doesn;t have the power of a terrestiral antennae and even pointed almost right at us the singal is weak.

the reverse is not true.
triplehelix
1 / 5 (9) Sep 17, 2013
El_Nose. My point still stands surely? If smart life is out there and their terrestrial antennae aren't that great, the signal would be almost completely lost, and that's after figuring out where the signal is, let alone just blindly sweeping the cosmos in little bursts in an attempt to find something. Also, it is only 17 light hours away, the closest stars are 4.5 light years away is 515x further away, and aren't capable of holding intelligent life. The closest stars with Earth like planets are magnitudes of distances longer. Surely if they're using radiowaves on their planet, the signal even if they're using their own terrestrial antennae, would be incredibly weak if not non existent? Wouldn't it be distorted and absorbed by the journey to us? Christ I can't get any TV reception when one cloud appears, from a few miles away, let alone thousands of light years through hot clouds of hydrogen etc.

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