Voyager 2 probes interstellar space --------------------------------- Plasma detector Cosmic ray detector Charged particle detector High-gain antenna Data takes 17 hours to travel back to Earth Human to scale Voyager 1 Launched Sep 5, 1977 Voyager 2 Launched Aug 20, 1977. Radioisotope thermoelectric generators (RTGs) will last about five more years Our Solar System MILKY WAY GALAXY NASA estimates galaxy is 100,000 light-years across. Since light travels at 300,000 kilometres per second, one light year is around 9,460 billion km Magnetometer Detects change in direction of magnetic field at edge of Solar System --------------------------------- SOLAR WIND: Stream of electrically charged plasma – mostly electrons and protons – flowing from Sun at speeds of up to 900km/s and temperature of one million degrees C --------------------------------- HELIOSPHERE: Sun’s solar wind creates plasma bubble that shields Solar System from galaxy’s high-energy cosmic rays. Voyager 2 data show that instead of fading out gradually, boundary is quite distinct --------------------------------- TERMINATION SHOCK: Point where speed of solar wind drops abruptly as it encounters effects of interstellar wind --------------------------------- HELIOPAUSE: Boundary where lower-density plasma of solar wind meets cold, higher-density plasma of interstellar space. Voyager 2 has confirmed interstellar particles punch into heliopause and solar particles extend more than 160 million km beyond heliopause --------------------------------- SOLAR SYSTEM HELIOSHEATH: Particle detectors monitor significant change – solar particles plummet while rate of cosmic rays increases dramatically Sun Saturn Jupiter Earth Pluto Uranus Neptune INTERSTELLAR SPACE: Voyager 2 traversed heliopause, 17.85 billion km from Sun, on Nov 5, 2018. Voyager 2 data show interstellar particles exert up to 10 times as much pressure on heliosphere than previously thought HELIOSHEATH TERMINATION SHOCK HELIOSPHERE HELIOSPHERE TERMINATION SHOCK HELIOPAUSE Voyager 1 Voyager 2 INTERSTELLAR WIND --------------------------------- Sources: NASA, Nature Astronomy © GRAPHIC NEWS