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Voyager: at edge of our solar system

  1. Jun 28, 2013 #1
  2. jcsd
  3. Jun 28, 2013 #2
    it would be interesting to see just where our solar system stops, The older thought of boundary was shown different by voyager.
  4. Jun 29, 2013 #3


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    Discovering the limits and properties of the sun's heliosphere seems to be an interesting if puzzling experience for the scientists involved. I would like to know if what they are finding about our own star would likely apply generally to other stars of similar size and type?


    Scientists initially thought that Voyager’s transition into this new realm, where effects from the rest of the galaxy become more pronounced, would be gradual and unexciting. But it’s proven to be far more complicated than anything researchers had imagined, with the spacecraft now encountering a strange region that scientists are struggling to make sense of.

    “The models that have been thought to predict what should happen are all incorrect,” said physicist Stamatios Krimigis of the Johns Hopkins University Applied Physics Laboratory, who is lead author of one of three new papers on Voyager appearing in Science on June 27. “We essentially have absolutely no reliable roadmap of what to expect at this point.”

    The sun produces a plasma of charged particles called the solar wind, which get blown supersonically from its atmosphere at more than 1 million km/h. Some of these ions are thrown outward by as much as 10 percent the speed of light. These particles also carry the solar magnetic field.

    Eventually, this wind is thought to hit the interstellar medium – a completely different flow of particles expelled from the deadly explosions of massive stars. The extremely energetic ions created in these bursts are known as galactic cosmic rays and they are mostly blocked from coming into the solar system by the solar wind. The galaxy also has its own magnetic field, which is thought to be at a significant angle to the sun’s field.

    Researchers know that Voyager 1 entered the edge of the solar wind in 2003, when the spacecraft’s instruments indicated that particles around it were moving subsonically, having slowed down after traveling far from the sun. Then, about a year ago, everything got really quiet around the probe. Voyager 1’s instruments indicated at the solar wind suddenly dropped by a factor of 1,000, to the point where it was virtually undetectable. This transition happened extremely fast, taking roughly a few days.

    At the same time, the measurements of galactic cosmic rays increased significantly, which would be “just as we expected if we were outside the solar wind,” said physicist Ed Stone of Caltech, Voyager’s project scientist and lead author of one of the Science papers. It looked almost as if Voyager 1 had left the sun’s influence.

    So what’s the problem? Well, if the solar wind was completely gone, galactic cosmic rays should be streaming in from all directions. Instead, Voyager found them coming preferentially from one direction. Furthermore, even though the solar particles had dropped off, the probe hasn’t measured any real change in the magnetic fields around it. That’s hard to explain because the galaxy’s magnetic field is thought to be inclined 60 degrees from the sun’s field.

    No one is entirely sure what’s going on.
  5. Jul 4, 2013 #4
    But that is the really cool thing about it, all the same, is that we managed to get something working that far out and still obtain useful data concerning what things are like out there!

    My take on what was presented in the article is that Voyager might now be passing through the true bow shock wave. The solar particles piling up & deflecting with the voyager plowing through it (and maybe noticing what the interstellar medium is going to be like).
  6. Jul 15, 2013 #5
    Oh wow This is cool. I always thought the edge of our solar system was the Oort Cloud. Is this past that point or is it still coming? Also how in the world do they make a battery last 36 years? I know they said Plutonium but is it a reactor or a battery? How do you make a battery out of Plutonium?
  7. Jul 15, 2013 #6


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    It's pretty much up for debate. You could classify it as the oort cloud, but that's WAAAAY out there at around 1 light year I think. Voyager 1 is nowhere near it yet and wont be for a very very long time.

    It's not a battery, it's a radioisotope thermoelectric generator. They basically just let a couple of big blocks or pellets of plutonium sit there and decay. The natural decay process heats the block of plutonium up to several hundred degrees. There's a thermocouple connected to a heat sink that uses the heat generated by the plutonium to generate electricity, with the wasted heat radiated off into space via the heat exchangers in the heat sink.


    Due to loss of plutonium from the decay, along with aging of the thermocouple and other components, the power from the RTG's on each Voyager spacecraft has dropped to about 60% what it was at launch.
    Last edited: Jul 15, 2013
  8. Jul 15, 2013 #7


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    The Oort cloud has been hypothesized but never confirmed or observed. It is a great convenience to explain the source of long period comets.
  9. Jul 22, 2013 #8
    Is it possible that Voyager could continue to function until it reaches the next star?

    It would also explain how Neptune and Uranus have their moons.
  10. Jul 22, 2013 #9
    lol not likely the speed of the probe is approximately 17 km/sec, the nearest star other than our sun is 4.2 light years away. So at that speed it would take roughly 70,588 years to arrive.

    assuming the travel speed from this link is correct and Voyager can maintain its currect speed.


    edit forgot to calculate number of sec per year lol the above is only how long voyager would travel 4 light seconds also forgot to handle the travel per year for Voyager.

    the corrected value is 17,647 years
    Last edited: Jul 22, 2013
  11. Jul 22, 2013 #10
    I knew it was a long time such as that. :tongue:

    It could be possible if nothing disturbed it, the plutonium contained inside it should decay long enough. Plus with just a vacuum around it, nothing can rot it away etc..
  12. Jul 22, 2013 #11
    Unfortunately no, from what I can tell from the link MFB provided they used a plutonium 238 pellet. That has a half life of 88 years
  13. Jul 25, 2013 #12
    The generators will be useless pretty soon - at least inside of the next 20 years or so. The half life of the isotopes is part of the problem, but the thermocouples are also losing efficiency due to age. Eventually it will reach the point that the isotope's generated heat won't be enough to provide enough power to the aging thermocouples, to continue running Voyager's systems. Voyager itself will continue, of course - but by the time it reaches the next star system, the human race may be extinct.
  14. Jul 25, 2013 #13


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    Hee hee.

    Voyager 1
    [source: http://xkcd.com/1189/]

    With mouseover:
    So far Voyager 1 'left the Solar System'; by passing through the termination shock three times, the heliopause twice, and once each through the heliosheath, heliosphere, heliodrome, auroral discontinuity, Heaviside layer, trans-Neptunian panic zone, magnetogap, US Census Bureau Solar System statistical boundary, Kuiper gauntlet, Oort void, and crystal sphere holding the fixed stars.​
  15. Jul 25, 2013 #14
    Cool! Didn't know that!


  16. Sep 12, 2013 #15
  17. Sep 12, 2013 #16


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  18. Sep 12, 2013 #17
    yes, I saw that news on TV just as few minutes ago.

    The lead scientist said istrumentation is being gradually turned off to conserve power and all systems will be shut down around 2025.....and Voyager will orbit our solar system from then on.
    I did not quite understand that last part.
  19. Sep 13, 2013 #18


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    Depends how you define the solar system.

    Voyager 1 has just entered interstellar space. That's a description of its environment.

    If you consider the Oort cloud to be part of the solar system (objects in interstellar space that still orbit the Sun), then Voyager 1 still has a ways to go.

    But, entering interstellar space is still a huge deal...

    ... and a good time to listen to the Voyager's Golden Record: Voyager Golden Record

    It looks like they've even reprinted the book about the making of the Golden Record: Murmers from Earth: The Voyager Interstellar Record

    I have the original hardcopy version of the book and its pretty fascinating - especially the chapter on trying to figure out how to format a message that some unknown alien race might actually understand.
    Last edited: Sep 13, 2013
  20. Sep 13, 2013 #19


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    Lets hope whatever alien race finds the record rocks!

    Go Voyager go!!
    Last edited by a moderator: Sep 25, 2014
  21. Sep 13, 2013 #20

    To be clear, NASA is saying that they now agree that Voyager entered interstellar space a year ago.
    Last edited by a moderator: May 6, 2017
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