The Voyagers space probes are two of humanity’s most remarkable achievements in space exploration. Launched in 1977, these twin probes—Voyager 1 and Voyager 2—have traveled farther than any other human-made objects. The Voyagers’ discoveries have given us incredible insights into our solar system and beyond.
In this article, we will explore what the Voyagers are, how they are powered, why they were launched, and, most importantly, the most significant Voyagers discoveries made so far.
What Are the Voyager Probes?
Voyager 1 and Voyager 2 are deep-space probes designed by NASA to explore the outer planets and the boundaries of our solar system. They were launched in 1977 as part of the Voyager program, a mission to study the gas giants and gather data about interstellar space.
Despite being over 46 years old, these probes are still sending back valuable information, pushing the limits of space exploration.
The Purpose of the Voyagers
The main reason for launching the Voyager probes was to take advantage of a rare planetary alignment that happens once every 176 years. This alignment allowed a spacecraft to visit Jupiter, Saturn, Uranus, and Neptune using a technique called gravity assist, where a planet’s gravity helps accelerate the spacecraft without using additional fuel.
NASA saw this as a golden opportunity to explore the outer planets in detail, and they certainly made the most of it! Let’s dive into some of the greatest Voyagers discoveries that changed our understanding of the universe.
The Most Important Voyagers’ Discoveries
The Voyager probes have sent back groundbreaking data, helping us learn more about planets, moons, and interstellar objects, and space. Here are some of their most significant findings.
1. The First Detailed Images of Jupiter and Its Moons
Voyager 1 reached Jupiter in 1979, giving us the first close-up images of the planet’s swirling storms and massive size. The probes also made a shocking discovery—Jupiter’s moon Io has active volcanoes! This was the first time scientists had observed volcanic activity beyond Earth. Io’s eruptions are fueled by gravitational forces from Jupiter and its other moons, making it one of the most geologically active places in the solar system.
The images taken by the Voyager probes showed a surface covered in lava flows, volcanic pits, and massive plumes erupting into space. Some of these volcanic plumes reached heights of over 190 miles (300 km), making them the tallest volcanic eruptions ever recorded. Scientists were amazed by how different Io was compared to other moons—it looked more like an alien world than a typical rocky moon.
The discovery of volcanic activity on Io reshaped our understanding of planetary geology, proving that celestial bodies far from the Sun could have internal heat sources powerful enough to drive massive geological processes.
Additionally, Voyager discovered that Jupiter’s massive magnetic field interacts with Io, creating intense radiation belts and electrical currents. These electric currents generate auroras on Jupiter, similar to the Northern Lights on Earth. This finding helped scientists understand how planetary magnetic fields interact with their moons, influencing space weather and radiation environments around gas giants.
2. Saturn’s Intriguing Atmosphere and Rings
Both Voyagers flew past Saturn, revealing new details about its famous rings and atmosphere. They discovered that Saturn’s rings are made of countless tiny particles, ranging from dust-sized grains to house-sized chunks of ice. These rings, though appearing solid from Earth, are actually delicate structures shaped by Saturn’s gravity and the influence of its many moons.
Voyager’s observations helped scientists identify distinct gaps in the rings, such as the Cassini Division, a large empty space between Saturn’s rings caused by gravitational interactions with its moon Mimas. These gaps revealed that the rings were not static structures but dynamic systems influenced by the planet’s gravitational forces and interactions with orbiting moons.
The probes also provided a closer look at Saturn’s atmosphere, uncovering massive storm systems, high-speed winds, and unusual cloud formations. One of the most fascinating findings was the discovery of a hexagon-shaped storm at Saturn’s north pole. This bizarre six-sided jet stream, spanning nearly 20,000 miles (32,000 km) across, remains one of the most mysterious atmospheric phenomena in the solar system.
The storm’s unique shape has intrigued scientists for decades, and subsequent missions have continued studying its behavior.
3. The Only Close Encounter with Uranus and Neptune
Voyager 2 is still the only spacecraft to have visited Uranus and Neptune. It flew by Uranus in 1986 and Neptune in 1989, revealing new details about these distant planets. Some key discoveries include:
- Uranus spins on its side, likely due to a massive collision in the past.
- Neptune has the fastest winds in the solar system, reaching speeds of up to 1,500 miles per hour (2,400 km/h).
- Neptune’s largest moon, Triton, has geysers that spew nitrogen gas, making it one of the most unusual moons in the solar system.
4. The Edge of the Solar System and Interstellar Space
One of the most exciting Voyagers discoveries is that both probes have now crossed into interstellar space. Voyager 1 left the heliosphere (the bubble of solar wind that surrounds our solar system) in 2012, and Voyager 2 followed in 2018. This means they are now traveling through the space between stars!
By studying interstellar space, the Voyagers have provided valuable data about cosmic rays, magnetic fields, and the environment outside our solar system. This is crucial information for understanding how our Sun interacts with the galaxy around it.
What Is the Power Source of the Voyagers?
Since solar panels (or solar sails) wouldn’t work well in the dark reaches of space, the Voyager probes use Radioisotope Thermoelectric Generators (RTGs) for power. These RTGs convert the heat released by the decay of plutonium-238 into electricity.
Over time, this power source slowly depletes, meaning the probes will eventually lose the ability to communicate with Earth. However, they have been incredibly efficient, lasting decades beyond their expected lifetimes.
How Long Will the Voyagers Be in Space?
The Voyager probes are on a one-way trip through the galaxy. Even after they stop transmitting, they will continue drifting through space for billions of years. Long after Earth and the Sun have changed, the probes will still be out there, silently traveling through the cosmos.
In fact, if they ever encounter an alien civilization, they each carry a Golden Record, a message containing sounds and images from Earth, including music, greetings in 55 languages, and sounds of nature. The records also include scientific information about humans, animals, and our planet, designed to communicate who we are to any intelligent life that might find them. While there is a slim chance of intercepting the probes, they serve as a time capsule of humanity’s existence.
Because of their incredible speeds, the Voyager probes will eventually pass near other star systems. In about 40,000 years, Voyager 1 will come within 1.6 light-years of a star in the Camelopardalis constellation, while Voyager 2 will pass near the star Ross 248 in approximately 42,000 years. Though they won’t be able to send data back, their journey will continue indefinitely.
How Long Can We Still Receive Data?
As of now, the Voyagers are still sending back data, but their power is fading. Scientists estimate that by 2025, the probes will lose the ability to communicate with Earth because their power supply will no longer be strong enough to keep the instruments running. Until then, NASA is carefully shutting down non-essential systems to extend their lifetimes as much as possible.
Currently, NASA engineers are prioritizing the most critical scientific instruments. Some instruments are already off to conserve power, but the Voyagers continue to send back valuable data about interstellar space. The team is also making occasional adjustments to extend their lifespan, such as modifying how they communicate with Earth to reduce power consumption.
Once the probes go silent, they will officially become dead spacecraft, drifting through space without sending any more signals. Even though they won’t be able to send new data, their legacy will endure. Scientists will continue analyzing the wealth of information they have provided for decades to come, making the Voyagers one of the most successful space missions in history.
Conclusion: The Lasting Legacy of the Voyager Probes
The Voyagers discoveries have transformed our understanding of the solar system and beyond. From active volcanoes on Io to the discovery of interstellar space, these spacecraft have provided insights that no other mission has. Even though their time is running out, they will continue their silent journey through the cosmos, carrying humanity’s message to the stars.
As we look ahead to future deep-space missions, the legacy of Voyager 1 and Voyager 2 will live on as some of the greatest space explorers of all time. Who knows? Maybe one day, another intelligent civilization will come across them and learn about the incredible species that sent them on their way.
Συχνές Ερωτήσεις (FAQs)
What major landmarks did Voyager 1 and 2 help discover in our solar system?
They flew past Jupiter, Saturn, Uranus, and Neptune. Along the way, they discovered dozens of new moons, revealed previously hidden rings, and captured the first close-up images of many of these planets and their satellites.
How did Voyager reveal active geology and storms on other worlds?
Voyager spotted active volcanoes on Jupiter’s moon Io and icy geysers on Neptune’s moon Triton. It also documented massive storms like Jupiter’s Great Red Spot and the jets on Saturn, showing planets as dynamic, changing worlds.
Why is Voyager 1 considered the first human-made object in interstellar space?
After crossing the heliopause—the outermost boundary of our solar system—Voyager 1 entered interstellar space in 2012. It now continues to send back data about cosmic rays, magnetic fields, and particles beyond the reach of the Sun’s influence.
What keeps the Voyager probes working decades after launch?
Engineers have carefully managed the spacecraft’s aging systems, reconfiguring memory units and selectively powering down instruments to extend mission life. As a result, Voyager continues to provide scientific data—and may remain functional into the 2030s.