NASA’s New Horizons spacecraft is hurtling out of our solar system at incredible speed. It’s currently about 8 billion kilometers from the Sun, and by the time you finish reading this article, it will be thousands of kilometers further into the frigid darkness. Space is lonely; even the giant planet Jupiter is just a tiny speck.
New Horizons is best known for getting the first proper glimpses of the dwarf planet Pluto in 2015, which it had only seen as a faint smudge until then. It also taught us a lot about the outer solar system and the tiny frozen worlds that float there. “It’s really been an Alice in Wonderland kind of story,” says Alan Stern, the mission’s principal investigator. “It’s been a magical experience, and we’ve made some amazing discoveries.”
But the dream isn’t over yet, because New Horizons may make a surprise final move. In early 2024, one of New Horizons’ detectors recorded an unexpected increase in the amount of dust it encountered. That material could have been created by collisions between rocky fragments, and astronomers now suspect that there may be many objects beyond the rubble-strewn Kuiper Belt, often considered the edge of the solar system. If so, the boundaries of the solar system would need to be redrawn, calling into question models of the formation of the solar system.
Stern and his colleagues are clearly hoping to take advantage of the rover’s unique position to learn more about this unexplored wilderness while they still can. “This is…
