How do you measure the milestones in your life? We all have events that help us mark the passage of years: school and jobs, marriage and family, births and deaths. These are of course primary in all our lives, but the recent encounter of the New Horizons spacecraft with the Pluto system has reminded me of the very special period of time that my own life has spanned. In the last 65 years, we have slipped the bonds of gravity that held us to the Earth and completed a survey of our solar system. Nothing comparable has happened since the great age of Earth’s exploration begun 500 years ago; nothing comparable is likely to happen for decades or centuries to come.
I was barely three weeks old when the first rocket was launched from Cape Canaveral, Florida in July 1950.
I was fifteen years old and completely obsessed with space when Mariner 4 flew by Mars in July 1965 and sent back the very first pictures of another planet.
Mars had no canals! Instead, it had moon-like craters and a disappointingly desolate appearance. As it turned out, Mariner 4’s flyby path took it over some of the least interesting of Mars’ topography. It fell to Mariner 9, which settled into orbit around the planet late in 1971 and patiently waited while global dust storms abated, to discover the solar system’s largest (extinct) volcano and a chasm that could swallow Earth’s Grand Canyon in one gulp.
But perhaps the greatest planetary explorers of all time were the twin Voyager spacecraft launched in 1977. Both Voyager 1 and Voyager 2 explored Jupiter and Saturn and their moons, while Voyager 2 was directed on to Uranus and Neptune. The images that the latter craft took of these giant planets are the only close-ups we are likely to see in our lifetimes.
And now, 50 years to the day after those first grainy black-and-white images from Mars that so astounded us, we have our first images of Pluto, taking four and a half hours to travel over 3 billion miles, and providing our first clues to new mysteries of planetary formation that await us.
It is a remarkable time to be alive. I can’t help but wonder what it must have been like for people greeting Captain Cook and Joseph Banks on the English docks in 1771 as they returned with stories of exotic Pacific Islands and hundreds of miles long coral reefs. How their world must have been enlarged by this new knowledge!
The world is much larger than our own dust mote of a planet, larger even than the system of planets that circles our life-giving star. But we have completed an important first round of exploration of the vastness that surrounds us.