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 imagination like Sputnik had done a generation before.
When I was finishing up my doctorate in geology, Voyager 1 responded to orders transmitted to it by NASA and 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 darkness of space. On that one little speck we all live – a sobering reminder that our Earth may be large compared to the dimensions of familiar objects like streets and houses, but it is tiny compared to the vastness of the solar system.
For quite some time after that image was made in 1990, Voyager 1 continued zooming away from us and from the sun, traveling at about 38,000 miles per hour. Zipping along at that rate it traveled father and 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.”
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.