Great Expeditions: 50 Journeys that changed our world. Levison Wood

Pale Blue Dot

      The Voyager spacecraft are powered by plutonium radioisotope thermoelectric generators, but to preserve energy NASA have had to systemically shut down Voyager’s instruments. In 1990, its cameras were switched off but before doing so, one final image was taken by Voyager 1, the ‘Solar System Family Portrait’. It was dubbed ‘Pale Blue Dot’ by the astronomer Carl Sagan as Earth appears as no more than a fraction of a pixel in the image.

      With the main mission objectives complete but both spacecraft still functioning, albeit with fewer instruments still operational, the mission now became the Voyager Interstellar Mission. Its objective was to explore the edges of the Solar System beyond the outer planets to the outer limits of the Sun’s sphere of influence, and potentially beyond.

      Deep space traveller

      In 2012, Voyager 1 reached the outer edges of the Solar System and entered the transition into interstellar space. This is the space between star systems within our galaxy. As the ships move further into deep space the effects of the solar wind from our sun decrease and the interstellar galactic wind increases. When the ships’ sensors finally detect only a background reading of particles originating from within the Solar bubble, and detect that the direction of the magnetic field has changed, NASA will finally announce that Voyager 1 has fully entered interstellar space.

      Around 2025, power will finally run out on the spacecraft but they will continue to travel through space long after everything mankind has, or will ever build has gone. Currently, they are 4 light years away from Sirius, the brightest star in the heavens. In just 290,000 years, they will arrive there!

      ‘Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives … on a mote of dust suspended in a sunbeam.’

       Carl Sagan, in his book ‘Pale Blue Dot’

      Timeline for Voyager 1 and 2.

The American Frontier

       Lewis and Clark’s Corps of Discovery expedition

      “They collect the wild fruits and roots, attend to the horses or assist in that duty, cook, dress the skins and make all the apparel, collect wood and make their fires, arrange and form their teepees, and when they travel, pack the horses and take charge of all the baggage; in short the man does little else except attend his horses hunt and fish.

       Meriwether Lewis on the role of the Shoshone woman, August 19 1805.

       WHEN

      1804–6

       ENDEAVOUR

      To explore the huge and unknown new territory recently gained by the United States.

       HARDSHIPS & DANGERS

      The explorers faced an ever-present threat of violence from native tribes. They also experienced severe hunger, exhaustion and frostbite.

       LEGACY

      The expedition realized the moral right of United States to extend across the continent to the Pacific. It brought back hundreds of previously unknown species, as well as detailed maps of previously uncharted areas.

       The men could go no further.

      Frostbitten, lame and hungry beyond reason, they stood at the apex of a continent. Behind them lay the full length of the mighty river that they had spent sixteen exhausting months paddling, trekking, and rowing up. Ahead of them, they had expected to see another river, one that would give them food and a gentle ride down to the ocean. Instead, they saw a monstrous range of icy mountains. They would need horses and many days’ supplies to cross them and the only natives they had found were refusing to offer them anything. This, truly, was the end of their journey. They would never reach their destination.

      Then the woman stepped forward. And their fortunes changed forever.

      It had begun with Napoleon Bonaparte.

      In 1803, the French Emperor was preparing for the seemingly inevitable war with Britain. As part of its overseas empire, France then owned ‘Louisiana’ — not the US state we know today, but a vast tranche of land comprising all or part of fourteen modern states. This territory was difficult for France to control remotely and, in a war, would be threatened by British forces coming through their territories in what is now Canada. ‘Why not simply sell Louisiana to the United States?’ counselled Napoleon’s minister of finance. They could fill their war chest with cash and divest themselves of an expensive colonial encumbrance at one and the same time. President Thomas Jefferson snapped the area of the United States. The land cost less than three cents an acre.