Voyager 2 Sends First Message From Interstellar Space

  • photo of voyager 2 in space with black background

    Voyager 1 and Voyager 2 are identical space probes that were sent into space in 1977, taking advantage of an alignment of the planets that only occurs once every 175 years. The probes took different routes: Voyager 1 visited Jupiter and Saturn, and got gravity assists from both of them before going to the edge of the universe. Voyager 2 paid a visit to Jupiter, Saturn, Neptune and Uranus (the only spacecraft that's ever seen the last two planets). 

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  • diagram of heliosphere around sun and termination shock

    After it visited Uranus in 1989, Voyager 2 wandered around the universe doing little missions here and there until it passed the termination shock and then entered into the heliosheath, which are two layers of the 'bubble' of particles and magnetic fields surrounding the Sun, passing much closer to the sun than Voyager 1 did when it made the same journey. Voyager 2 passed through the termination shock in November 2018 and officially entered interstellar space

    Voyager 1's instruments were damaged when it entered interstellar space, so scientists weren't able to track it's movements closely. But Voyager 2's instruments are all intact, and since it exited our universe a year ago, scientists have been able to study the information relayed by the probe and build a better understanding of the boundaries of interstellar space. 

  • diagram of our sun's heliosphere and interstellar space

    Voyager 2 has five science instruments on it: a magnetic field sensor, two instruments for studying plasma, and two instruments to detect energetic particles in different energy ranges. Combining the findings of all these instruments, researchers were able to figure out where the environment created by our Sun ends, and where the vast unknown of interstellar space begins. 

    The Sun's heliosphere (the bubble of space that surrounds, and was created by the sun - our universe exists inside it) is filled with plasma (gas that has electrons stripped from some of it's atoms), and interstellar space is also filled with plasma. The plasma inside the heliosphere is hot and sparse, while plasma in interstellar space is cold and dense. The space between stars in interstellar space also contains cosmic rays, or particles accelerated by exploding stars. The planets in our galaxy are protected from the radiation of cosmic rays by the heliosphere. 

  • photo voyager 2 with black and blue starry universe behind it

    The new research also confirms that Voyager 2 isn't actually in undisturbed interstellar space yet; it's in a perturbed transitional region just beyond the heliosphere. Other findings show that there is a compression of plasma where the boundary of the heliosphere is, although they don't know what's causing it. 

    Voyager 2 will continue to send new information about interstellar space back to Earth, although it will take many more years for it to reach undisturbed interstellar space: where the sun really doesn't shine. Who knows, maybe that's where all the aliens are hiding


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