Sections

Services

Information

UK United Kingdom

Voyager 1 is leaving the solar system, but the journey continues

At 18.5 billion kilometres from Earth, the Voyager 1 space probe is the most distant human-made object ever to leave our planet. And now the spacecraft, which was launched in September 1977, has discovered…

Voyager 1 has come across an unexpected region of the solar system - a “magnetic superhighway”. NASA

At 18.5 billion kilometres from Earth, the Voyager 1 space probe is the most distant human-made object ever to leave our planet.

And now the spacecraft, which was launched in September 1977, has discovered a new region at the edge of our solar system.

Voyager 1 is now entering what space scientists think is the final region of the “heliosphere” - the bubble of charged particles the sun blows around itself - before it reaches interstellar space.

For a spacecraft that’s now in the darkest reaches of the solar system, it’s easy to forget its mission is really all about the sun.

Voyager 1 and 2 are now in the “Heliosheath” - the outermost layer of the heliosphere where the solar wind is slowed by the pressure of interstellar gas. NASA

On Earth, we are at the mercy of solar flares, coronal mass ejections, and the vast amounts of electromagnetic energy and particles those phenomena fling our way. We can’t see these particles, but they can take out power grids and exposed satellites.

There are several missions close to the sun, including NASA’s Solar Dynamics Observatory, which is studying the dynamics of the sun, 36,000km from Earth. Questions of interest include: where does the sun’s energy come from? And how is it stored and released in the sun’s atmosphere?

Voyager 1 is at the other end of the solar system, where the solar wind starts to meet with particles and magnetic fields from outside the solar system. And it seems that the interaction is more complex than we could have predicted.

Interstellar turbulence

Since December 2004 Voyager 1 has been travelling in the “heliosheath” where the solar wind has slowed from supersonic speeds and become turbulent.

This set of animations show NASA’s Voyager 1 spacecraft exploring a new region in our solar system called the “magnetic highway.” In this region, the sun’s magnetic field lines are connected to interstellar magnetic field lines, allowing particles from inside the heliosphere to zip away and particles from interstellar space to zoom in.

From August 2012 Voyager 1 has entered a region where these solar winds have sped up and where high-energy particles from outside the solar system are also entering the heliosphere.

According to Edward Stone, Voyager project scientist:

Voyager 1 still is inside the the sun’s environment, we can now taste what it is like on the outside because the particles are zipping in and out on this magnetic highway.

It’s an intense magnetic region that was not expected from models and will take some time to understand and interpret.

This discovery is remarkable in itself - more remarkable in that it was reported by an instrument designed in the early 1970s.

This graphic, made from data from Voyager 1, tracks the behaviour of the sun’s magnetic field and a population of charged particles as the spacecraft moved in and out of a new region scientists are calling the “magnetic freeway ”. The top graphic (magenta) shows the intensity of the magnetic field. The intensity jumped each time Voyager 1 entered the new region. These data come from Voyager’s magnetometer. The bottom graphic (blue) shows the prevalence of lower-energy charged particles that originate from inside our heliosphere, which is the bubble of charged particles around our sun. These data come from the cosmic ray instrument. Each time Voyager 1 entered the new region, the population of these inside particles dropped. After Aug. 25, the magnetic field intensity has held steady at the same elevated level and the population of inside particles hit an all-time low and has not changed. Scientists refer to this new region as a “magnetic highway ” because here the sun’s magnetic field lines are connected to the interstellar magnetic field lines. This connection allows particles from inside the heliosphere to zip away. It also allows particles from interstellar space to zoom in. NASA/JPL-Caltech/GSFC/University of Delaware

Old-time tech

Data from Voyager 1’s ten instruments, including three cameras, are stored on a 500 megabit (62.5MB) tape recorder.

That is sufficient capacity to store about 100 images or a few graphs worth of data at a time, before it is beamed to Earth as a stream of binary data, with a theoretical upper rate of 14.4 kilobits per second, a rate far slower than a dial-up modem of 56 kilobits per second.

Both Voyager spacecraft – you might remember that Voyager 1 has a twin, Voyager 2 – have three computers. One decodes commands from Earth and issues them to the other two, one handles data from the instruments, and one manages the spacecraft.

The computers have a tiny amount of memory, with memories ranging from 4 to 8KB, barely enough to run a modern car’s trip computer.

This time-lapse video records Voyager 1’s approach to Jupiter during a period of more than 60 Jupiter days. Source: NASA

It’s not about the destination …

On its journey to the extremities of the sun’s influence, Voyager 1 revealed Jupiter’s rings and moons to us in May 1979. It flew by Saturn, snapping photos of the planet’s rings and the mysterious hazy atmosphere of Saturn’s moon Titan.

Then it left the ecliptic – the plane in which most of the planets orbit the sun – heading “up”, out of the solar system.

The hazy atmosphere of Saturn’s moon Titan, as seen by Voyager 1 on November 12, 1980. NASA

During 1998 Voyager 1 overtook the slower Pioneer 10 and 11 crafts – which were launched to investigate Jupiter and more – becoming the furthest human artefact from Earth. It’s a record that’s likely to stand for some time, given Voyager 1 is travelling at some 520 million kilometres a year.

Its twin, Voyager 2, was actually launched before Voyager 1, on August 20, 1977. Its interplanetary grand tour took it past Jupiter in July 1979, Saturn in August 1981, Uranus in June 1986 and Neptune in August 1989. Now travelling at a mere 470 million kilometres every year it is heading out of the solar system, below the ecliptic plane.

Both Voyagers took advantage of a planetary alignment that only occurs once every 170 years. Their trajectories enabled the Voyagers to receive a gravity-assisted boost to their speed and direction. Without this, the trip to Neptune would have take 30 rather than ten years and they would be far short of their current positions.

Image of Saturn taken by Voyager 2. NASA

Echoes in space

Currently, our sense of the interstellar boundary comes from the merest whisper. Voyager 1 outputs 23W of radio power - barely even a glow by light-bulb standards. We hear this whisper on Earth at the limit of NASA’s Deep Space Network, requiring the pooled resources of two antennae at whichever site is in contact, at a ghostly 6x10^-18 W - an almost unimaginably small signal.

This remarkable spacecraft represents the extent of our physical senses in the solar system. From the surface of the Earth, our astronomers can remotely sense faraway galaxies and observe intergalactic events far into the distance and deep in time.

But closer to home, there’s so much we don’t know. And opportunities to continue our exploration outside the bubble are limited.

Voyager 1’s batteries are expected to run out of power towards 2050. NASA

Powering down

Voyager 1 has only five functioning instruments left from its original ten. As the power in its plutonium-238 batteries runs down towards 2050, the instruments will be turned off one by one, much like house lights winking out in the night.

Voyager 1’s whisper will at last fall silent and the same fate awaits Voyager 2.

How will we feel when we can no longer “see” beyond the enigmatic borders of the sun’s influence? How will we feel when the solar system appears to contract around us?

Of course, even when the two Voyagers stop communicating with Earth, their journey will continue apace, pushing beyond the confines of our solar system into the unfathomable vastness beyond.

Join the conversation

33 Comments sorted by

  1. John Harland

    bicycle technician

    What are "supersonic speeds" in deep space?

    report
    1. Kevin Orrman-Rossiter

      Research Partnerships Officer at University of Melbourne

      In reply to John Harland

      John good question. The speed of sound still is a physical quantity of meaning in gases and plasmas (the solar wind is a dilute gas) and is related to its temperature and density. Physical features that we are familiar with sound in our atmosphere, shock waves etc are still a physical reality in the solar wind. A useful reference is:
      http://en.wikipedia.org/wiki/Speed_of_sound
      I trust this is useful.

      report
  2. Mark Amey

    logged in via Facebook

    Fantastic stuff, and all on less computing power than a modern wristwatch.

    The Voyagers deserve the Nobel Prize!

    report
  3. mixmaxmin

    logged in via Twitter

    To Voyager 1 - Bon voyage certainly applies. What an accomplishment! Keep on keeping on :)

    report
  4. Stuart Purvis-Smith

    Clinical Cytogeneticist (retired)

    Wonderful mind-stretching stuff but surely this blog would not be complete without a "science denier" or two !?

    report
  5. Ron Chinchen
    Ron Chinchen is a Friend of The Conversation.

    Retired (ex Probation and Parole Officer)

    And in a few hundred thousand perhaps many million years, our travelling trailblazer will perhaps enter a solar system and swing around its sun, while a newly awoken technological species watch and wonder from their orbiting planet, at its purpose and origins and that they are not alone in the Univerese. They may even attempt to travel into space to observe it, or fear it as some invasion from another world. And it will swing by its sun and continue its eternal journey through the cosmos oblivious of the attention. And just perhaps one talented writer from that species may write a record of its journey and call the book Rendezvous With Rama

    report
    1. Kevin Orrman-Rossiter

      Research Partnerships Officer at University of Melbourne

      In reply to Ron Chinchen

      Ron very nicely put.

      In the near term Voyager 1 will have a closest approach of 1.64 light years to the star AC + 79 3888 in the year 40272, and Voyager 2 to 1.65 light years to Ross 248 40170. They do not approach any closer to stars within 500000 years - I have not seen calculations beyond that!

      report
  6. Don Gibbons

    Clerk

    Lord Tennyson would have loved JPL missions;

    Old age hath yet his honour and his toil;
    Death closes all: but something ere the end,
    Some work of noble note, may yet be done,
    Not unbecoming men that strove with Gods...
    My purpose holds to sail beyond the sunset,
    And the baths of all the western stars until I die...
    Tho' much is taken much abides; and tho'
    We are not now that strength which
    In old days moved earth and heaven,
    That which we are, we are;
    One equal temper of heroic hearts,
    Made weak by time and fate, but strong in will
    To strive, to seek, to find, and not to yield.

    report
  7. Yoron Hamber

    Thinking

    It seems so incredibly well made, Voyager. I'm extremely impressed and hope we will keep getting data until 2050. It flares the imagination reading you :)

    report
  8. John Harland

    bicycle technician

    You have missed my favourite Voyager story.

    As I understand it, the main antenna of Voyager 1 failed to unfurl so all the data on Jupiter and Saturn was going to have to be sent back through the lower-bandwidth backup antenna.

    Faced with this, the technicians managed to incorporate then-new data compression techniques into the software. From Earth they were able to reprogram the spaceprobe a million or so kilometres distant.

    With that new software, the probe was able to transmit more data to Earth through the backup antenna than the original capacity of the main antenna.

    To me it is one of the most-inspiring stories in software development. I hope it was not just a myth.

    report
  9. Blair Donaldson

    logged in via Twitter

    Thank you Kevin and Alice for this update on the wonderful journeys of the Voyager spacecraft.

    It seems that today, anything to do with space is just ho-hum and younger generations take he benefits of space research for granted.

    I'm glad I was born at a time when I could experience the wonder and suspense of the moon landings and the excitement of the planetary encounters as each Voyager spacecraft zipped by them.

    It was interesting watching the surprise and wonder many of the mission specialists displayed as new photographs and other evidence was returned to Earth. Human imagination seems to constantly underestimate the strangeness of the solar system and the cosmos.

    It would be interesting to know what the cost of the mission has been over the years for the science it has returned as a comparison to the money wasted on mega churches and alternative medicine…

    report
    1. Kevin Orrman-Rossiter

      Research Partnerships Officer at University of Melbourne

      In reply to Blair Donaldson

      I am afraid I can't make a detailed analysis of the cost of Voyager over the years. The NASA budget for the 'planetary' grand tour of the two Voyagers was US$360M in May 1972 (I will let someone more certain to convert this into 2012 $s).

      However this figure does not include the upgrades that were made to the Deep Space Network during this period. There was a call for the DNS to be shut down as its function was for tracking Voyager at that time. Fortunately saner heads prevailed as it now tracks many probes including Curiosity on Mars. I am yet to find cost for the current phase - although it is a small team. According to the briefing the team is 12 FTE at JPL for a science team of 5.

      Rather small enterprises compared to your comparison 'organisations' I think you will agree.

      report
    2. Ron Chinchen
      Ron Chinchen is a Friend of The Conversation.

      Retired (ex Probation and Parole Officer)

      In reply to Blair Donaldson

      Worth every cent and more. Such research is surely a fundamental of human purpose. Our whole existence, the life style we now live, has been the result of the investment past people have put into researching, going all the way back to learning what herbs and spices are of value, what stones are best for making blades etc etc.

      You talk of today's apathy, but the interest is still there. Its just for a time looking in other areas and that's OK. The search into space will always have highs and lows of enthusiasm amongst the masses and will always have a small percentage who keep the enthusiasm alive. Dont despair. Space will have its time again and again.

      report
    3. Ron Chinchen
      Ron Chinchen is a Friend of The Conversation.

      Retired (ex Probation and Parole Officer)

      In reply to Blair Donaldson

      Just be glad that you lived through that magical period, that will never come again. The revelation of so much in astrononmy about the Solar System and the Universe, that was known by no one before us. We have lived through a special time in history that for the young is now second nature, but for those living since the 1950's, a dawning of a new age.

      report
    4. Blair Donaldson

      logged in via Twitter

      In reply to Blair Donaldson

      Ron, no doubt about it, we have lived in a special time all right. I suppose I feel frustrated that more people don't feel the same way I do about space exploration (and science generally) or understand how much we have moulded our lives around science.

      Imagine the chaos if our communications were knocked out for even a short time. Most day-to-day activities would grind to a halt. It's that lack of appreciation and understanding that concerns me most.

      Hopefully the Voyager missions, Curiosity on Mars, Cassini and others will keep the enthusiasm alive as you say.

      report
    5. Ron Chinchen
      Ron Chinchen is a Friend of The Conversation.

      Retired (ex Probation and Parole Officer)

      In reply to Blair Donaldson

      I guess Blair that we the baby boomers and perhaps X Gen experienced the wonder step y step, whereas others today are fed it in science journals et al as an established fact like the discovery of evolutionary processes is to us (thought there are some pretty naive beliefs that the majority of the world still holds to about this issue even well over a century past its revelation).

      I guess also seeing so much develop, you become almost addictive to the process (I know I do). As Oliver Twist says…

      Read more
  10. Emma Anderson

    Artist and Science Junkie

    This whole deal with leaving the heliosphere in particular is the most awesome thing ever. Human ingenuity,curiosity and wanderlust at its finest.

    I have heard there is some debate as to the exact details of "when" exactly the solar system ends and the voyage out of it begins, but I get the impression from this article in particular that we're finding things out longer after the fact due to the distance of the craft. So Voyager N may be well outside already and who knows what data comes next…

    Read more
    1. Blair Donaldson

      logged in via Twitter

      In reply to Emma Anderson

      Emma, I love your enthusiasm. I checked on the JPL website, when Voyager 1 finally breaks into interstellar space, we should know after about 17 hours.

      It's hard to imagine such a tiny little speck of man-made technology so far away from home.

      I wonder what Carl Sagan would think about the latest news?

      report
    2. Emma Anderson

      Artist and Science Junkie

      In reply to Emma Anderson

      Blair, cheers but what's not to like? I mean come on :)

      Uhm. I don't know much about the late great Dr. Sagan, but, from what I've seen, he'd probably be a bit like David Attenborough on camera. That is, trying very hard to be composed and serious presenter like when inside he is so giddy with excitement and madly in love with what an awesome thing he gets to do for a living that we can all see through the poker face. Pretty much I'm guessing that this means Carl would probably jump up and down and yell "yahoo!" and dance like a maniac off camera, swinging everyone by the arms and running into every pub in whatever town he's in speaking in jibberish about how great it all is.

      report
    3. Blair Donaldson

      logged in via Twitter

      In reply to Emma Anderson

      It was Carl Sagan and his "Cosmos" series that rekindled my interest in science. He was very good at explaining complex science in away the layman could understand. If you get the chance, find the Cosmos series on DVD and watch them – excuse the 1970s fashions – each episode explains a particular concept, evolution, planetary motion, the atom etc and gives a historical context so you can understand the long, tortuous path that led to the eventual discoveries.

      An update of the series is being produced by Neil deGrasse Tyson, I think it is supposed to be released in late 2013

      report
    4. Ron Chinchen
      Ron Chinchen is a Friend of The Conversation.

      Retired (ex Probation and Parole Officer)

      In reply to Emma Anderson

      Blair. I was also a fan of Carl Sagan and very sad he died so young. He did have a talent for making things seem simple and wondrous. I would suggest to you someone else who is developing this talent in Britain's Professor Brian Cox. Looks late 20s but is actually mid 40s with extensive knowledge in physics, astronomy etc. He is the front man in many of the recent 'Universe' series of docos and he has an infectious style of presenting his subjects that is also very simple and wondrous. Top presenter.

      report
    5. Blair Donaldson

      logged in via Twitter

      In reply to Emma Anderson

      Ron, thanks for the heads up on Brian Cox but don't worry, I have seen his first series and was very impressed. In many ways he is like Carl Sagan with similar abilities to explain and inspire wonder.

      As for his youthful looks, maybe he's cracked the secret of time travel but isn't letting on? :-)

      He is also possesses a great wit. Track down a BBC podcast called "the infinite monkey cage", guaranteed you'll get a chuckle or several.

      report
    6. Emma Anderson

      Artist and Science Junkie

      In reply to Blair Donaldson

      Thanks for letting us know about that Blair

      D/loaded the show and got distracted for a long time. Very enjoyable podcast. Shared the fun with others too.

      Cox is an awesome presenter can tell he loves what he does and why not he gets to talk about the universe :)

      report
  11. Comment removed by moderator.

  12. John Harland

    bicycle technician

    It was magic teaching astronomy at Junior Highschool level in the early 1980s when the data from Saturn was coming in.

    Well, as good as Junior Science gets to be, anyway (to get in before anyone accuses me of rose-coloured memory)

    report
  13. Ahmed fathy elsayed

    logged in via Twitter

    Reminds me of Pirates of the caribbean : at World's ends ..... now that felt like a journey to the world's ends...+ felt like we still don't know alot of stuff ... + GOD gave us much powers enabling us to reach these levels .. still felt like we are so tiny ... :)

    report
  14. Kevin Orrman-Rossiter

    Research Partnerships Officer at University of Melbourne

    As of April 24, 2013 a gauge on the Voyager home page, http://voyager.jpl.nasa.gov, tracks levels of two of the three key signs scientists believe will appear when the spacecraft leave our solar neighborhood and enter interstellar space.

    When the three signs are verified, scientists will know that one of the Voyagers has hurtled beyond the heliosphere.

    The gauge indicates the level of fast-moving charged particles, mainly protons, originating from far outside the heliosphere, and the level…

    Read more
    1. Emma Anderson

      Artist and Science Junkie

      In reply to Ron Chinchen

      LOL Ron I was thinking about Star Trek ever since this article was first published.

      Thanks for the update Kevin - as they say 2/3 ain't bad....so darn close....*crosses fingers*

      Maybe we should clean up our act down here what with some alien potentially suing us for false advertising they might see on Voyager?

      report