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NASA’s Voyager 2 Spacecraft Has Slipped Into Interstellar Space

By Alexandra Lozovschi
Published on: 04:20 PST, Dec 10, 2018

NASA has just made a major announcement about its pioneering Voyager 2 spacecraft. Forty years after it launched from Cape Canaveral Air Force Station, the intrepid probe has now entered interstellar space — and is poised to eventually make its way out of the solar system, the space agency confirmed earlier today.

According to this latest update, the Voyager 2 probe has officially left the heliosphere, or the vast protective bubble of charged particles and magnetic fields stretching around the sun and its planets. Judging by the readings of four instruments on board the spacecraft, Voyager 2 crossed the boundary of the heliosphere, known as the heliopause, on November 5.

In doing so, the spacecraft has joined Voyager 1 in interstellar space, thereby becoming the second human-made object to ever reach the space between the stars.

“Its twin, Voyager 1, crossed this boundary in 2012, but Voyager 2 carries a working instrument that will provide first-of-its-kind observations of the nature of this gateway into interstellar space,” NASA officials said in a statement.

To discuss Voyager 2’s crossing into interstellar space — and what it means for the spacecraft to venture beyond the edge of the sun’s influence — the space agency is hosting a news conference today, starting at 11 a.m. EST. The event is held at the meeting of the American Geophysical Union in Washington, and can be watched on NASA Live.

Going Interstellar

As the Inquisitr previously reported, Voyager 2 has been navigating the outermost layer of the heliosphere, called the heliosheath, for the past 11 years. Last month, the probe finally breached through the heliopause, and is currently sailing the uncharted waters of interstellar space.

The confirmation has come from Voyager 2’s Plasma Science Experiment (PLS) instrument, which is tasked with picking up data on the outflow of plasma coming from the sun, also known as the solar wind. This outflow is what makes up the heliosphere — which envelops all the planets in our solar system, stretching well beyond the orbit of Pluto until it reaches the termination shock — or the point where the motion of its particles slows abruptly.

This artist's concept shows the outer layers of our solar bubble, or heliosphere, and nearby interstellar space.
This artist’s concept shows the outer layers of our solar bubble, or heliosphere, and nearby interstellar space.

On November 5, the PLS recorded “a steep decline in the speed of the solar wind particles,” explained NASA.

“Since that date, the plasma instrument has observed no solar wind flow in the environment around Voyager 2, which makes mission scientists confident the probe has left the heliosphere.”

The data was corroborated by detections from three other onboard instruments, namely the probes’ low energy charged particle instrument, the magnetometer, and the cosmic ray subsystem — which in late August signaled that Voyager 2 could be approaching interstellar space. This inference came after Voyager 2 detected an increase in cosmic rays coming from outside of our solar system.

Put together, the data points to the same conclusion — that Voyager 2 has slipped outside the heliopause, and into interstellar space.

Artist's illustration showing the position of NASA's Voyager 1 and Voyager 2 probes outside of the heliosphere.
Artist’s illustration showing the position of NASA’s Voyager 1 and Voyager 2 probes outside of the heliosphere.

The probe is currently more than 11 billion miles from Earth, and can still call home to communicate with mission controllers. However, its signal, which travels at the speed of light, takes a whopping 16.5 hours to reach our planet.

“By comparison, light traveling from the sun takes about eight minutes to reach Earth,” notes NASA.

The next step for the Voyager 2 team is to study the data received from the probe, gleaning as much information as possible on the interstellar space immediately beyond the heliopause.

“I think we’re all happy and relieved that the Voyager probes have both operated long enough to make it past this milestone,” said Suzanne Dodd, Voyager project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “This is what we’ve all been waiting for. Now we’re looking forward to what we’ll be able to learn from having both probes outside the heliopause.”

Leaving The Solar System

Although both Voyager 1 and Voyager 2 have now crossed into interstellar space, it will take a long while before the spacecraft actually leave the solar system.

As NASA explains, the border of the solar system is considered to lie beyond the outer edge of the Oort Cloud — a spherical shell of icy comets found well beyond the system’s outermost planets. While the exact size of the Oort Cloud is unknown, scientists estimate that it begins at 1,000 astronomical units (AU) from the sun, or 1,000 times the distance between the sun and the Earth.

This massive region of deep space is estimated to span about 100,000 AU. This means that it will take Voyager 2 about 300 years to reach the inner edge of the Oort Cloud — and up to 30,000 years to cross it, and emerge on the other side.

Artist's concept of the Voyager spacecraft in space.
Artist’s concept of the Voyager spacecraft in space.

The Voyager Mission

Launched in 1977, the twin Voyager spacecraft were originally intended to embark on a five-year mission to study the two biggest planets of our solar system, Jupiter and Saturn. After successful flybys of the two gas giants, their mission was extended to Uranus and Neptune — the outer gas giants of the solar system.

Their epic journey has carried them farther into space than any other man-made spacecraft has ever ventured, pushing their life-span to an incredible 41 years.

“Voyager has a very special place for us in our heliophysics fleet,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters. “Our studies start at the sun and extend out to everything the solar wind touches. To have the Voyagers sending back information about the edge of the sun’s influence gives us an unprecedented glimpse of truly uncharted territory.”

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