Voyager Found a Strange Region Beyond the Solar System

 

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For decades NASA’s Voyager spacecraft have been traveling into the darkness than any other human-made spacecraft. After leaving the planets behind Voyager 1 and Voyager 2 eventually crossed the boundary where the Sun’s influence begins to fade and the surrounding interstellar environment becomes dominant.

What the spacecraft encountered beyond that boundary turned out to be far more complicated than scientists once expected.

Voyager Entered a Different Environment

The region beyond the heliosphere is not simply empty space. As Voyager traveled outward its instruments began detecting changes in the surrounding plasma, magnetic field and charged particles. The spacecraft had crossed into the medium. The material that exists between stars. This was a moment in space exploration because Voyager was effectively sampling an environment that no spacecraft had directly studied before.

The Edge of the Solar System Is Not a Simple Wall

Scientists once imagined the boundary of the system as something relatively straightforward. In reality the outer edge is extremely dynamic. The Sun continuously releases a stream of charged particles called the wind. This creates a bubble around the solar system known as the heliosphere. Eventually the solar wind becomes too weak to dominate its surroundings. That transition creates the heliopause.. Instead of being a perfectly smooth boundary the region appears to be much more complicated.

Voyager Detected Something Unexpected

After entering space Voyagers instruments detected changes in the density of plasma surrounding the spacecraft. The measurements suggested that the space beyond the heliopause contains structure than scientists originally expected. The spacecraft also encountered variations in fields and energetic particles. These observations indicate that the boundary between the Suns environment and interstellar space is a region where two very different cosmic environments interact.

A Hidden Boundary in Deep Space

One of the aspects of the discovery is that the boundary cannot simply be seen. There is no line or visible barrier separating the solar system from interstellar space. Instead Voyager had to detect the transition through changes in particles and magnetic fields. It was after analyzing the spacecrafts measurements that scientists could determine that Voyager had entered a fundamentally different environment.

The Sun Still Has an Influence

Even after Voyager crossed the heliopause the Sun was not completely irrelevant. The solar wind and magnetic field continue to influence the region around the heliosphere. Particles from the Sun can interact with particles arriving from space creating a complicated mixture of environments. This makes the outer solar system more dynamic than a simple bubble surrounded by empty space.

Voyager Is Essentially a Cosmic Sensor

Voyagers importance goes beyond the famous photographs it sent back during its planetary encounters. Its scientific instruments are still measuring the environment around the spacecraft as it travels away. Every measurement provides another piece of information about the space between stars. The farther Voyager travels, the distant the spacecraft becomes from the familiar environment created by the Sun.

What Lies Ahead?

Voyager is continuing its journey into space. At these distances communication with Earth is extremely difficult and the spacecraft has only a limited amount of power remaining. Eventually its scientific instruments will no longer be able to operate.. The data collected before that happens could remain valuable for decades. Future spacecraft may use Voyagers observations as a reference when studying the boundary of other planetary systems.

The Region Beyond the Solar System Is Still a Mystery

Voyagers journey has shown that the edge of our system is not a simple border. It is a transition zone filled with particles, magnetic fields and interactions between the Sun and the wider galaxy.. Voyager is still moving outward. Every kilometer it travels takes humanity into a region no human has ever visited. Ahead lies the vast interstellar space between the stars. A place where Voyager will continue carrying the story of our solar system long after it has disappeared from the skies, above Earth.