When I was a baby in the early 1960s, President John F. Kennedy famously said we should put a man on the moon within the decade. I was in grade school when we met that deadline, landing men on the moon in the summer of 1969.
My family gathered around the TV to listen to Walter Cronkite announce the events of the lunar landing. My father took pictures of the television screen with his 35 mm camera – he deemed the event that important.
When I was in high school in 1977, a much longer-term exploratory effort was launched. Two unmanned space probes, Voyager 1 and Voyager 2, lifted off from Earth in quick succession. The idea behind the Voyager probes was to fly past planets in the middle and outer solar system and keep going into interstellar space.
When I was in college, Voyager 1 did a fly-by of Jupiter and then Saturn. In addition to images of these large, gaseous planets, the probe sent back pictures of their moons. The transmissions fired people’s imaginations.
When I was finishing up my doctorate in geology, Voyager 1, responding to orders transmitted by NASA, turned to look back at Earth. The image the probe made was transmitted to us and we saw our planet as a “pale blue dot” hanging in the vast darkness of space.
For quite some time after that image was made in 1990, Voyager 1 continued zooming away from the sun, traveling at about 38,000 mph. Zipping along at that rate it traveled farther toward the edge of our solar system. Eventually it moved beyond the orbit of Uranus, Neptune and finally Pluto. During that time I went from being a woman in her prime to one with arthritis in both her knees. Now, 36 years after it was launched, Voyager 1 has traveled almost 12 billion miles and reached another milestone of space exploration, leaving behind our solar system and moving into interstellar space.
“Voyager has gone a long way,” Michael Allen said to me. Allen is a faculty member in physics and astronomy at Washington State University. “Light travels enormously quickly, but it takes more than 17 hours for light from where we are on Earth to travel out to where Voyager 1 is now.”
Allen explained to me that Voyager 1 is moving fast enough to escape the sun’s gravitational field, but not so quickly it will ever escape from our galaxy.
Using a special telescope, we have recently detected the faint radio signal coming from Voyager 1. That amazes me because Voyager’s transmitter is a tiny 22 watts. From what I’ve read, that’s about the strength of a radio transmitter in a cop car.
It’s taken most of a lifetime to go from visiting the moon to having a probe cruising in interstellar space. But we’ve now done what few could imagine before I was born.