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voyager 1 at the final frontier

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presented by science at nasa

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for nearly 35 years nasa's voyager 1

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probe has been hurtling toward the edge

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of the solar system flying through the

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dark void on a mission unlike anything

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attempted before

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one day mission controllers hope voyager

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1 will leave the solar system behind and

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enter the realm of the stars

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interstellar space

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that day may be upon us

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the latest data from voyager 1 indicate

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that we are clearly in a new region

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where things are changing quickly says

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ed stone voyager project scientist at

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the california institute of technology

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in pasadena

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this is very exciting we are approaching

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the solar system's final frontier

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the frontier he's referring to is the

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edge of the heliosphere a great magnetic

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bubble that surrounds the sun and

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planets

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the heliosphere is the sun's own

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magnetic field inflated to gargantuan

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proportions by the solar wind

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inside lies the solar system

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home

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outside lies interstellar space where no

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spacecraft has gone before

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a tell-tale sign of the frontier's

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approach is the number of cosmic rays

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hitting voyager 1.

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cosmic rays are high-energy particles

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such as protons and helium nuclei

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accelerated to near-light speed by

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distant supernovae and black holes

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the heliosphere protects the solar

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system from these sub-atomic bullets

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deflecting and slowing many of them

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before they can reach the inner planets

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as voyager approaches the frontier the

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number of cosmic rays has gone up

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from january 2009 to january 2012 there

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had been a gradual increase of about 25

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percent in the amount of galactic cosmic

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rays voyager was encountering says stone

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more recently however we have seen a

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very rapid escalation in that part of

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the energy spectrum

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beginning on may 7 2012

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the cosmic ray hits have increased five

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percent in a week and nine percent in a

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month

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the sharp increase means that voyager 1

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could be on the verge of a breakthrough

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18 billion kilometers from earth when

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voyager 1 actually exits the heliosphere

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researchers expect to see other changes

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as well

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for one thing energetic particles from

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the sun will become scarce as the

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spacecraft leaves the heliosphere behind

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also the magnetic field around voyager 1

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will change direction from that of the

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sun's magnetic field to that of the new

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and unexplored magnetism of interstellar

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space

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so far neither of these things has

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happened

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nevertheless the sudden increase in

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cosmic rays suggests it won't be long

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meanwhile voyager 2 is making its own

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dash for the stars but because of its

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slower pace lags a few billion

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kilometers behind voyager 1.

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both spacecraft remain in good health

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when the voyagers launched in 1977 the

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space age was all of 20 years old says

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stone

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many of us on the team dreamed of

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reaching interstellar space but we

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really had no way of knowing how long a

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journey it would be

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or if these two vehicles that we

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invested so much time and energy in

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would operate long enough to reach it

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as the space age nears the 55-year mark

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there is little doubt the voyagers are

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going the distance