NASA's New Horizons probe crossed Neptune's orbit Monday on its way to Pluto, which is significant because the was the 25th anniversary of Voyager 2's historic Neptune flyby.
NASA is calling it a cosmic coincidence.
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It's the last major intersection for New Horizons, which is due at Pluto next summer after nearly a decade of travel, The Associated Press reported.
Neptune wasn't exactly close to the spacecraft Monday. In fact, the planet was 2.5 billion miles away.
Scientist Alan Stern of the Southwest Research Institute in Boulder, Colorado, says this will be the first opportunity in a generation to explore a new planetary system up close. New Horizons will study not only mysterious Pluto, but also its moons, some of which might still be hiding from us.
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