John Stonestreet and G. Shane Morris: Voyager 2’s Departure from Our Solar System is a Reminder of How Vast the Universe Is and How Small We Are

The Hubble Space Telescope has imaged striking details of the famed planetary nebula designated NGC 2818, which lies in the southern constellation of Pyxis (the Compass). The spectacular structure of the planetary nebula contains the outer layers of a star that were expelled into interstellar space. | (Image: NASA and ESA)

If you want to feel small, just imagine moving at 34 thousand miles per hour for forty years and getting—astronomically speaking—nowhere.


Late last year, the Voyager 2 space probe became the second craft to ever leave our solar system. Now 11 billion miles from earth, it is one of the farthest-flung man-made objects in existence. And it was launched in 1977.

Because there are different ways of defining the solar system, we should be precise. The American Geophysical Union in Washington reports that Voyager 2’s sensors recently detected a sudden dip in radiation and magnetism, which marks the boundary of what astronomers call the “heliosphere,” our sun’s protective bubble of particles and magnetism.

In other words, the probe is now beyond our star’s most significant influences and is hurtling into interstellar space—literally “the space between the stars”—at 34 thousand miles per hour.

Its departure from the heliosphere is big news because, unlike its twin, Voyager 1, Voyager 2 is still transmitting data back to us here on earth, providing “first-of-its-kind” observations of the nature of this unexplored space.

Voyager 2 was originally designed to observe the gas giants Jupiter, Saturn, Uranus, and Neptune—a mission it completed back in 1989. But scientists now think the aging probe might hold together as late as 2027, depending on how long its plutonium fuel source provides power.

The accomplishment of both Voyager probes is unparalleled. Still, astronomically speaking, they’ve only just stepped outside our front door, and barely entered the larger stellar neighborhood. It will take Voyager 2 another 40 thousand years to approach the nearest star to our sun—which together occupy only a fraction of the Orion Arm of the Milky Way galaxy. The Milky Way, in turn, is just one of at least 100 billion galaxies in the visible universe.

In the distant reaches of space, there are stars so much bigger than our sun they defy description. The longtime record-holder for largest known star is VY Canis Majoris, a red hypergiant over two thousand times the size of our sun.

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SOURCE: Christian Post, John Stonestreet and G. Shane Morris