Ongoing Dispatches from the First Man-Made Object to Leave Our Solar System
On September 5, 1977, NASA launched Voyager 1, a small 700 kg space probe with a special mission: to boldly go where no one or no thing has gone before. The Voyager 1 was designed to explore the outer edges of our solar system and beyond, and it has been doing just that for more than four decades.
Voyager 1 had a twin, Voyager 2, which was actually launched 16 days earlier. Both were on similar missions, and working together they were able to send back detailed images and other data about Jupiter and its moons, Saturn and its moons, Uranus and Neptune.
During the initial stages of its trek, Voyager 1 focused on Jupiter and Saturn . It discovered two new moons orbiting Jupiter, and revealed the existence of volcanoes on Jupiter’s moon Io. This proved that large moons could be geologically active just like planets. As it approached Europa, the most well-known moon of Jupiter, it took pictures that seemed to confirm the planet was covered by ice, which could mean that there’s a liquid ocean below. Traveling further out, Voyager 1 also discovered two new moons of Saturn (Prometheus and Pandora), along with a brand new ring (which was labeled the ‘G’ ring) encircling the planet.
The encounters of Voyager 1 with Jupiter and Saturn occurred a long time ago, in 1979-80. It took the probe another 32 years after that to fully exit the Sun’s sphere of influence, which highlights the immense distance that separates our Earth from the edges of our solar system. Before we could even begin to contemplate sending manned missions to Jupiter and beyond, we would need to develop spacecrafts that are many times faster than those we have currently have in the developmental stage.
While Voyager 2 was launched first, the trajectory of Voyager 1 allowed it to exit the boundary of our solar system six years earlier than its partner probe, in August 2012. This boundary is defined as the point where pressure from the Sun’s solar wind is exactly equal to the collective pressure from interstellar winds (winds from other stars).
The region that surrounds this boundary is called the heliosphere, and this area has some unique characteristics of its own. It resembles a kind of protective bubble, where electron densities are significantly lower than they are in the solar system or even out in interstellar space. Voyager 1 was the first man-made object to explore the heliosphere, which in itself was an historic achievement.
On the other side of the heliosphere, readings sent back from Voyager 1 have revealed the presence of intense cosmic radiation. Should high-speed interstellar spacecraft ever be developed, allowing us to transport living beings beyond the edges of the solar system, those craft would have to have extremely strong shielding to protect the astronauts from fatal radiation poisoning. This is a serious concern for space travel in general , as evidenced by the fact that cardiovascular disease (which can be caused by radiation exposure) has claimed the lives of the Apollo astronauts at levels far higher than the national average in the United States.
So far, Voyager 1 has covered about 21.7 billion kilometres since it left the launchpad almost 42 years ago. At its current cruising speed of 61,000 kph, it would take approximately 75,000 years for the probe to reach the nearest star, which is Proxima Centauri—provided, of course, that it was actually traveling in that direction, which it is not. In 40,000 years it will pass within 1.6 light-years of a star called, which in terms of interstellar space travel could be classified as a close encounter.
Four Decades of Service and Counting
When the Voyager missions were launched, NASA was unsure just how long they would continue to function. It was hoped they would stay active and whole long enough to reach interstellar space. But no one was certain if it would actually be possible.
Naturally, mission scientists are delighted by Voyager 1’s impressive longevity.
“None of us knew, when we launched 40 years ago, that anything would still be working, and continuing on this pioneering journey,” said NASA project scientist Ed Stone in an August 2017 statement marking the anniversary of the initial Voyager (2) launch. “The most exciting thing they [Voyager 1 and 2] find in the next five years is likely to be something that we didn’t know was out there to be discovered.”
Voyager 1’s power source will expire sometime in 2025. After that, it will lose the capacity to operate its scientific instrumentation or relay any information back to Earth. From that point on it will drift along through space in complete silence, utterly alone and stranded without the ability to transmit data about the wonders it may encounter.
But as of now it is still alive and well and is continuing to perform its mission efficiently and without interruption. For the next few years it will continue to beam back data that will be enormously helpful for astrophysicists and other space scientists seeking to expand their knowledge of nearby interstellar space.
Seeking Contact —for Better or Worse
Even if intelligent life is out there, speeding through the galaxy in near-light-speed spacecraft, searching everywhere for signs of life, the chances of it crossing paths with Voyager 1 would be infinitesimally small. As they travel through space Voyager 1 and Voyager 2 will remain the proverbial needles in the haystack, except in this case the haystack is large enough to span a distance of many light-years in all directions.
Nevertheless, NASA included a pair of gold-plated phonograph records in the Voyager 1 and Voyager 2 payloads, which will introduce human beings, human society and the planet Earth to any alien explorers that might stumble across the probe.
Among their contents, these copper discs contain more than 100 images and illustrations that cover a broad range of cultural, social, mathematical and scientific subject matter. This includes a detailed description of human anatomy and reproductive processes, and a stellar map that reveals the exact location of our planet and our Sun. The records also feature a variety of nature sounds, spoken greetings in 55 languages both ancient and modern, and special messages from U.S. President Jimmy Carter and U.N. Secretary General Kurt Waldheim (the latter choice of messenger was unfortunate, given later revelations that unmasked the Austrian Waldheim as a card-carrying member of the Nazi Party during the World War II era).
The committed that selected the content for these phonograph records was headed by the famed astronomer and popular science writer Carl Sagan.
“The spacecraft will be encountered and the record played only if there are advanced spacefaring civilizations in interstellar space,” Sagan acknowledged. “But the launching of this “bottle” into the cosmic ocean says something very hopeful about life on this planet.”
‘Hopeful’ is one word to describe the inclusion of this information. But ‘naive’ might be another.
Should a benevolent civilization discover Voyager 1, it would have a road map to follow to find us, and it would learn a lot of important facts about who we are and how we think, behave and function. But a race of interstellar predators scavenging the galaxy in search of precious metals, slave labor or a two-legged food source might be even more excited to find such a road map, along with valuable information that might make it that much easier to conquer us.
Either scenario is conceivable, should the Voyager 1 be picked up by extraterrestrial travelers. Then again, if a space-faring civilization did find our probe and examine its contents, they might be so unimpressed by our backwardness that they wouldn’t even bother to track us down.
One thing we do know is that unless it is hit by some type of space debris, the Voyager 1 will continue to float through the interstellar void for centuries after it loses the ability to communicate with Earth. That means it could be discovered long after its creators have passed away, meaning future generations may suffer the consequences for their ancestors’ mistakes—or enjoy the benefits of their wise decision to send out a beacon begging for contact.
By Nathan Falde
Voyager 1 has not left the solar system. The solar system includes the oort cloud. Voyager 1 would reach the Oort cloud in about 300 years and would take about 30,000 years to pass through it. The Oort cloud surrounds the Sun because of the Sun's influence, that is the gravitational influence. The voyager only flew past the heliosphere. The voyager 1 will be leaving the solar system in 30,000 years.