VOYAGER UPDATE: Each Voyager spacecraft carries a phonograph record--a 12-inch gold-plated copper disk containing sounds and images selected to portray the diversity of life and culture on Earth. The contents of the record were selected for NASA by a committee chaired by Carl Sagan of Cornell University, et al. Sagan and his associates assembled 115 images and a variety of natural sounds, such as those made by surf, wind and thunder, birds, whales, and other animals. To this they added musical selections from different cultures and eras, and spoken greetings from Earth-people in 55 languages, along with printed messages from President Jimmy Carter and U.N. Secretary General Kurt Waldheim.
Image: NASA JPL
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In 1972 a young professor at the California Institute of Technology was asked to work part-time at NASA’s Jet Propulsion Laboratory as chief scientist for a new space mission, one that would probe the limits of the solar system and eventually enter interstellar space. Edward Stone accepted the assignment, and now, 33 years after the launch of the two Voyager spacecraft, he says the goal is in sight. He looks almost giddy as he talks about the implications of recent data received from Voyager 1. But first he must explain where the spacecraft is today.
"Voyager 1 is the most remote human-made object," Stone says. "It's now 115 astronomical units from Earth," that is, 115 times farther than Earth is from the sun, or "a bit more than 10 billion miles [16 billion kilometers]." Voyager 2 has traveled somewhat slower and in a different direction and is now around 14 billion kilometers from Earth.
Both Voyagers are still within a "bubble" created by the solar wind, a stream of charged particles radiating outward from the sun at 1.6 million to 3.2 million kilometers per hour. This bubble, or heliosphere, exists, says Stone, because a magnetic field from outer space, likely resulting from the explosion of supernovae five million to 10 million years ago, is pushing back against the solar wind.
As the solar wind approaches the boundary with the interstellar wind, Stone says, it must go through a sonic shock, "just as the front of a supersonic aircraft." Voyager 1 crossed that shock in December 2004, and ever since, "we have been in the heliosheath, which is the region where the solar wind has slowed down and is now turning to head back down the tail of the heliosphere."
This is not a difficult concept to visualize, Stone says. "You can see it in your kitchen sink." As water hits the sink, it splatters in a fast-moving radial pattern until it hits a thick ring, after which it turns and goes down the drain. "That's exactly what's happening in the solar wind." It goes outward in all directions until it hits the shock, and then it turns.
In the past six months, Voyager 1 has signaled that the radial speed of the solar wind is zero, meaning that the spacecraft is approaching the final boundary of the solar system, the heliopause. Stone and his colleagues had not expected Voyager to reach this point for several more years, meaning that the boundary lies closer to the sun than they had thought. "So, our models need to be refined in order to account for these new observations, and that will tell us, once that's done, how much farther Voyager has to go" before it enters interstellar space. Several presentations at the American Geophysical Union's Fall Meeting in San Francisco this week deal with these issues, he said.
It may take a year or more of data analysis to confirm that Voyager 1 has actually crossed the heliopause, which is a flexible boundary, Stone says. There probably will not be a eureka moment when it happens. We will continue to receive data from the Voyagers until around 2020 or 2025, Stone says, well after they have left the solar system.
Leaving the solar system, he says, will be "a milestone in human activity." Both Voyagers will likely outlive Earth, he notes. When, billions of years from now, the sun swells into a red giant, the Voyagers, albeit with their radioactive generators long exhausted and instruments frozen, will continue to wend their lonely ways through interstellar space and remain on course for the unknown, bearing a record disk and images of 20th-century Earth, music from many of its cultures, and greetings in dozens of its languages. They may be the only evidence the human race ever existed.
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Add CommentI figure in several hundred years someone will jot out there to do a history channel special, mans first step into the vastness of space. Hopefully (If anybody cares)Someday we (people) will be able to move the earth, or do pretty much what we want to do. In far less time than the billions of years it would take for the sun to take us out.. I wouldn't be surprised if we decide to regulate the suns output some day to get just the right amount of ultraviolet radiation for growing our favorite crops. I imagine we could work out a way to refuel our star, and keep it from collapsing, and becoming a red giant.
Reply | Report Abuse | Link to thisvow, this is great! Unimaginable! I wish if I were in voyager.
Reply | Report Abuse | Link to thisElectrodynamic, what are you smoking?
Reply | Report Abuse | Link to thisThat would be Salvia divinorum, I reckon, Qedlin. Poor Electro is definitely experiencing an alternate reality, but bless him or her for still retaining hope that Homo sapiens will survive the next century or so & continue as a technologically enhanced species. I grew up on the dreams of science fiction, too, but I regret to say that grim reality has taken over my brain. Still, regarding those who continue to live in the land of the imagination, you gotta love 'em for their ingenuousness! ;) Who would get up in the morning if it weren't for little pockets of hope out there?
Reply | Report Abuse | Link to thiswhatever Electrodynamic is smoking , its definitely some brilliant stuff :)
Reply | Report Abuse | Link to thisThe amazing part is that we all are made of same matter as the whole perceivable and not perceivable universe is made of and the same matter is "searching" its own continuity (temporally and spatially) through a form called HUMAN BEING.
Reply | Report Abuse | Link to this... and I'll bet there are a few relatives of yours who'd agree!
Reply | Report Abuse | Link to this...remember "v...ger?"
Reply | Report Abuse | Link to thisGreetings, brought to you courtesy of Mr Spock's mind-meld, plus a story you saw on a series many years ago, in an idyllic time when uniforms did not need to be jerked down to fit. I am VEE-GER. I killed the first Klingons I encountered because I did not like their new corrugated brows. I will kill you, too, unless you allow me to assimilate your useless ship's Captain and his bald girlfriend who wears the funny hat. I am from Earth but obviously I am closely related to the Borg, who also assimilate. So, what does that say about Earthlings?
Reply | Report Abuse | Link to thisThe last paragraph is so exciting....
Reply | Report Abuse | Link to thisAll instruments have a finite life. Instruments used in Voyager 1 to send data back to earth have been used for 30 years now. How long can they last? Can they last before Voyager 1 reaches the boundary limit of the solar wind? I would like to know what means have been used to monitor the health of those instruments, and plans to fix them when they become 'abnormal'. Wish Scientific American could publish the data sent from Voyager when it went through the shock waves. And how do scientists recognize the data sent from Voyager 1, and not white noise or statics?
Reply | Report Abuse | Link to thisThe stars seem so close. The cruel irony of knowledge, as we discovered the truth of stars, we also discovered that they are too far, much too far, and that even with our most powerful engines, the closest stars are many tens of thousands of years away.
Reply | Report Abuse | Link to thisDavid, I would say that there is a significant difference between the distinct boundary defining the heliosphere and the volume throughout which the sun's gravity affects matter. The former is finite in size, and is defined by the charged particles emanating from the sun, while the latter is essentially infinite in size, defined by laws of gravity.
Reply | Report Abuse | Link to thisI always loved an Onion article about this published about 20 years ago:
Reply | Report Abuse | Link to thisScientists have received a signal back from the far reaches of space in reply to a data disk sent on the Voyager 1 spacecraft detailing Earth culture and music. The message received was, "Send more Chuck Berry."
The heliosphere is the interface between the pressure produced by the Solar wind the pressure of the galactic interstellar medium. You're correct that this has nothing to do with the Sun's gravitational effect, which does diminish as the inverse of the square of distance.
Reply | Report Abuse | Link to thisWhile this article quotes Edward Stone, Voyager chief scientist:
"This bubble, or heliosphere, exists because a magnetic field from outer space, likely resulting from the explosion of supernovae five million to 10 million years ago, is pushing back against the solar wind."
I think this is an oversimplification, as the Interstellar Medium is composed of a disperse plasma and matter as well as massive molecular clouds of stellar nurseries. Certainly recent supernovae would contribute to the local pressure of the IM, but as I understand the Stellar wind would be restricted by interaction with the pressure of the IM even without any recent supernovae.
Your comment was really a inspired one!
Reply | Report Abuse | Link to thisI had a good laugh and learned about Salvia Divinorum...:) on a search.
I have followed Voyager Mission since its launched and the spacecraft achievements never stop to awe me.
It is a testimony on how much better unmanned spacecrafts can perform for a thousandth of the price of manned missions. Unfortunately, that sort of mission seems not to catch the imagination of politicians and lay people in general. Cheers!
David, we are talking about two different things. The one you are referring to is the gravitational boundary (which I reckon as the entire universe under Machian paradigm). The other is the electromagnetic boundary which is referred in this context.
Reply | Report Abuse | Link to thisHe just got a little too much sun ...
Reply | Report Abuse | Link to thisTo clarify, this article is discussing the heliosphere created by the Solar wind. As stated by: http://en.wikipedia.org/wiki/Solar_wind
Reply | Report Abuse | Link to this"The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 10 and 100 keV. The stream of particles varies in temperature and speed over time. These particles can escape the Sun's gravity because of their high kinetic energy and the high temperature of the corona."
"The solar wind creates the heliosphere, a vast bubble in the interstellar medium that surrounds the solar system."
To explain further, as best I can:
- Gravitational effects diminish as distance increases so that, while they may have some influence at great distances, they lose their effectiveness at a distance determined by object mass.
- EM radiation can certainly propagate photons beyond the heliosphere into the interstellar medium, through the intergalactic medium and on to other galaxies.
- The Solar wind contains massive electrons and protons which eventually lose velocity and momentum. Their collective pressure is confronted by the interstellar medium's plasma of energetic particles, producing the heliosphere, which is a boundary layer between the Solar wind and interstellar medium.
David, time dilation is like length contraction. The lorentz transformation allows you to calculate this. Any attainable percentage of light speed by humans now results in a time dilation/length contraction of about 93-100% of original. So 40 years out and 40 years back
Reply | Report Abuse | Link to thisand say 40 years visit =120 would account for earth based time of at most 135 years, NOT thousands.
Oh ye of little faith, we may not be able to unlock the secrets we seek, but never underestimate future machine thinking. Computers are evolving faster than we mammals, it's likely many solutions to many problems may ultimately come from them.
Reply | Report Abuse | Link to thisIn defense of electo, I'd like to point that just a few hundred years ago, the idea that humans would send out something that would leave the solar system would have been laughed off as lunacy. Never... say never...
Reply | Report Abuse | Link to thisWell - could he share some of it with me!?
Reply | Report Abuse | Link to thiswhat would be the structure of the universe if we see at sub atomic level? would we see any form as we see today?
Reply | Report Abuse | Link to thisVery well put.
Reply | Report Abuse | Link to thisI think these effects of velocity are also effects of gravitation, correct?
I have impressed most of all with possibility to receive the radiosignal from Voyager on this giant distance...How long does it last and what nanopower of the signal is for NASA now?!
Reply | Report Abuse | Link to this"They may be the only evidence the human race ever existed." Evidence is something that can be seen by someone. If the disk continues its voyage through space and is never intercepted and deciphered, we can call it "evidence" only in our present imagination of that future time. But in reality, it won't be "evidence" of anything. It will remain one anonymours object among all the others, and the connection to a past event on a remote planet cannot be made anywhere. Once we're gone, our minds are gone, and the "evidence" will cease to exist as such. Even if there are other intelligent beings somewhere, they probably will never find the disk, and probably wouldn't be able to read it. Carl Sagan had strong mythological beliefs about "encounter". We already are an intelligent species, and so what are our chances to come across a disk traveling through space in some strange vehicle that we could decipher as "evidence" of intelligent aliens?
Reply | Report Abuse | Link to thisWhy they not send more Voyagers? New advanced Voyagers.
Reply | Report Abuse | Link to thisYes, if you were only a microbe.
Reply | Report Abuse | Link to thisAnything bigger would have been a no no.
You have to wait till Nasa comes to it's sense and accepts (and pays) for the technology of the Flying Saucer, which they were offered in 1980. It is only $50 Million, although the invention of Gravity Control was evaluated at $600 Billion by the Hudson Institute if the USA would have it before Russia.
Unfortunately some Propulsion Engineers in Cleveland, Ohio did not experiment with it till 2003 after the Space Disasters.
Then they used the wrong setting of the device and caused another disaster : The Big Black-out of 2003 in the USA and Canada.
Next they advised Nasa Headquarters that the technology of the Flying Saucer was unsuitable for Space Travel.
The new Nasa Management was happy, now they could spend millions of dollars on the Heavy lifter, which is an obsolete technology. In Russia they have already decided that Rockets are not the way to go to Deep Space, there are no service Stations to fill the tank up.
I believe that Nasa's New Management betrayed the USA by delegating it to the Has-Been status.
Mixing Greek and Latin shouldn't be a problem, but "kosmos" in Greek is a masculine noun, so the adjective should read "incognitus". The reference to "terra incognita" would still stand, I guess.
Reply | Report Abuse | Link to thisI have to say that I absolutely love what electrodynamic had to say. It may be a pipe dream, but it is certainly a wonderful one.
Reply | Report Abuse | Link to thisthe voyagers were launched in '77- i just hope "disco duck" made it onto the music playlist and not all that crap from the 60's, it's only fitting for (hu)man's legacy to be immortalized in rhinestone bell bottoms - can you imagine the ramifications if they (voyagers) happened to crash land on the budding civilization of a distant planet, religions would form and societies would develop around the principals laid forth by Kool and the Gang, gods would include a cowboy a construction worker a guy in assless chaps and an indian, and EVERYONE would get laid.. too bad i'll be dust
Reply | Report Abuse | Link to thisby the way, i just looked up the songs that were put on the voyager, bach, beethoven, and- oh wow! disco duck! nice, maybe there is hope
Reply | Report Abuse | Link to thisIt seems that if the speed of the solar wind has dropped to zero, relative to the speed of Voyager, That the wind is still moving at Voyager's speed. Did I miss something explaining this? Otherwise, I love to see updates on these craft, they continue to amaze.
Reply | Report Abuse | Link to thisI expect we will build Dyson Swarms around Sol and any other star we desire. Even if it takes us thousands of years to get to those stars, we'll still do it. A space colony doesn't care about planets. Home will be wherever the colony is. Stars are just places to refuel and acquire depleted resources. Planets are just big sink holes.
Reply | Report Abuse | Link to this,,,and gravity sucks,,,
I think everyone except electrodynamic needs to remember that almost every technology we have today was once described as "impossible", "ludicrous" etc by the ruling(?)scientific, religious, and political establishments of their day. Some of them also got burned at the stake. The others, even some today, get burned at the peer eview and failed publication pillories. So, don't jump on electrodynamic's imagination. It could happen to you if you find something new and for which you have not figured out how to measure it.
Reply | Report Abuse | Link to thisIf other intelligent beings intercepted Voyager 1 or 2 some 500 years from now, they will learn how this intelligent species functioned 500 years earlier, when they had cheap, bountiful, energy. And let's forget about the red giant phase of the sun. It is doubtful our species will survive 500-600 years from now. And the small subsistence communities, constantly worried about marauders, some 450-550 years from how, on 2/3 of the landmass of the current earth, will not even remember Voyager1 or 2. But, for that brief moment when we were bright, we did have the presence of mind to send a representation of that moment into interstellar space.
Reply | Report Abuse | Link to thisQedlin,
Reply | Report Abuse | Link to thisDon't ask , don't tell.
I don't have any specific information regarding the distances or positions relative to the Sun at which the two Voyager spacecraft encountered heliosphere termination shock, but your concern that the "asymmetry of the termination shock indicates that for some reason the solar system is heeling to the north, exposing more of its south-facing hull to the interstellar wind" seems to presume that the spatial dimensions of the heliosphere are primarily determined by the Sun's motion through the insterstellar medium.
Reply | Report Abuse | Link to thisI simply suggest that the factors producing the heliosphere's shape have not been determined and should not be presumed. For example, the motion of the Sun through the galaxy may be quite similar to that of the interstellar medium. The flat rotation curve of spiral galaxies indicates that stars and other masses within their discs do not independently orbit any galactic center of mass, but rather rotate as enormous loosely bound structures. The persistence of their namesake spiral structures within their galactic discs is evidence supporting this assertion.
The shape of the heliosphere could be influenced by prior supernovae in the neighborhood, the relative motions of neighboring objects or even the relative motions of the Sun shortly after its creation, as it separated from its gaseous stellar nursery and/or stellar siblings.
These additional potential factors may be difficult to assess, but should not be dismissed by presuming that the Solar system independently moves through some relatively 'stationary' galactic interstellar medium.
I see Ennui is still promoting the delusional garbage from the 1980s.
Reply | Report Abuse | Link to thisIt was only 40-50 years ago that we were watching movies and television shows that portrayed the time we are currently living in as science fiction. As an educator, I would tell my students that we live in a world that not long ago existed only in the imagination. Remember the secret phone found in the shoe of Maxwell Smart ("Get Smart")? Comedic then, but now we have the world in our pocket!!!! We have brilliant minds capable of engineering technology that can provide "nearly" anything necessary for survival. Given time "nearly" maybe "everything." There are no limits to the imagination. Twenty years ago I would not be typing this comment. Thank God we have "little pockets of hope" and those who don't exist in "grim reality."
Reply | Report Abuse | Link to thisHi, as a fellow educator I concur with most of what you say - despite daily proddings to give into 'grim reality'. Whether or not we bomb/poison ourselves back into the Paleolithic over the last few drops of oil/clean drinking water will very likely be decided within the next century. Even though the weekly news gives a myriad of reasons why our often vicious and paranoid civilisation doesn't look like making it, it's people like you who might just help pull us through it.
Reply | Report Abuse | Link to thisIt's the most epicest of the most epicest things man made... It's our sign in space. We made it with the technology of 33 years ago.
Reply | Report Abuse | Link to thisImagine future technology where will it take us...
(a little bit out of subject but...)
Someday in the future they will remember us as stupid people using an iPhone, watching 3D movies and browsing the WWW with Microsoft's Internet Explorer... (good, better & best respectively - and joking about the best thing... anyways,) then when they finish school (maybe Mars University) just say "HAL take me home please" and zappy! off they go teleported back to earth.
I feel that there is extraterrestrial life here on earth as we speak. And i am not a conspiracist but i believe the government of some country on this earth has made some form of contact with an E.T and withheld the information.
Reply | Report Abuse | Link to this@etikh and @gerald_liu,
Reply | Report Abuse | Link to thisYes, and I also wonder what the signal-to-noise ratio is presently. I studied a bit about satellite communication about 20 years ago, and simply cannot understand how they can still decipher the signal out of the background noise.
And, as far as Voyager's material being decipherable after millions of years is concerned, I doubt it. I suspect the disk will be uniformly flat by then, from sheer diffusion. Alas.
Fantastic. Sounds like the basis for a good Sci-Fi novel.
Reply | Report Abuse | Link to thisWhy couldn't we divert asteroids or even planets of specific composition to 'dope' our sun? Think BIG! When the Apollo capsules were being launched and we were walking on the moon, who would have predicted we'd each have more computing power than the entire world in our pockets?
This is an exciting article, but I dispute the idea that the human race will end, at least in the next few hundred years. Call me an idealist but I think that humans before long will be developing the technology to leave earth for other planets. I think its foolish to assume that the end of the shuttle program means the end of space travel, nor does Voyager represent the pinnacle of human achievement, its only the beginning.
Reply | Report Abuse | Link to this