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Part 1 of 3 Parts
       For the most part, I have blogged about space around the Earth. Occasionally I have ventured out into the Solar System. Very rarely, I have written about missions beyond our Solar System. Today I am going to blog about a such a mission.
        Ralph McNutt works at the Johns Hopkins University of Applied Physics Laboratory. Now sixty-five, he has been interested in interstellar travel since he was a teenager. He is currently drafting a plan that would send a probe ninety-three billion miles into interstellar space. This is about one thousand times the distance between the Sun and the Earth which is referred to as one astronomical unit. The probe would explore the conditions beyond the Solar System. The probe would take about fifty years to reach its destination. It is likely that everyone involved in launching the probe will be dead by the time it achieved its objective.
      McNutt and his team hope to be chosen when U.S. space scientists release a list of their top research priorities. In order to get their mission on the agenda, they must convince their colleagues that the goal of the mission is scientifically valuable. Of course, it will have to be politically viable in its competitions with many research worthy topics on the Earth and in the Solar System.
       Our Sun is in a minor arm of the Milky Way galaxy. The Milky way is about one hundred thousand light years across. The Earth is about twenty-five thousand light years from the center of the Milky Way which, about half the way to the rim. The Earth is currently traveling about half a million miles per hour. It is hit by gusts of gas and dust and pounded by highly energetic particles whose origins are unknown. The surface of the Earth is shielded from this rain of gas, dust and particles by what is called the “heliosphere.” This is a stream of charged particles called the solar wind which streams out past all the planets to the very edge of the Solar System. Out beyond the Solar System, there is a region known as the “heliopause.” This is the buffer zone between the solar wind and the ocean of dust and gas in interstellar space. It is the boundary between our Solar System and the interstellar environment.
       Only two Earth probes have ever reached the heliopause while still functioning. The two probes were referred to as Voyagers. They were launched in 1977 and it took over thirty-five years for them to reach the boundary. Other probes have traveled out of the Solar System, but they had stopped functioning by the time they reached the heliopause. Some of the instruments on the Voyager probes have failed and their radio transmissions have become fainter and fainter.
       Voyager 1, the most distant object ever built by humanity is now one hundred and forty-five astronomical units. At the rate that it is traveling, it will take two hundred and eighty-three years to make it to the region targeted by McNutt.
Please read Part 2 next