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New Horizons spacecraft crosses Neptune orbit on trek to Pluto

NASA’s New Horizons spacecraft is nearing the end of its long journey, passing Neptune’s orbital path on Monday, Aug. 25, 2014.
NASA’s New Horizons spacecraft is nearing the end of its long journey, passing Neptune’s orbital path on Monday, Aug. 25, 2014.
NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The National Aeronautics and Space Administration (NASA) on Monday announced that the New Horizons spacecraft crossed the orbital path of the Solar System’s eighth planet Neptune on its way to its scheduled July 14, 2015 flyby of the dwarf-planet Pluto and its five known moons.

“No country except the United States has the demonstrated capability to explore so far away,” Alan Stern, New Horizons principal investigator at the Southwest Research Institute in Boulder, Colo. stated.

He continued, “The U.S. has led the exploration of the planets and space to a degree no other nation has, and continues to do so with New Horizons. We’re incredibly proud that New Horizons represents the nation again as NASA breaks records with its newest, farthest and very capable planetary exploration spacecraft.”

New Horizons is now 2.75 billion miles from Earth. To illustrate the vastness of such a distance, it now takes light from the Sun over four hours to reach New Horizons. In comparison, light from the Sun takes approximately 8.3 minutes to reach the Earth.

The spacecraft officially crossed the Neptune’s orbital path at 10:04 pm EDT on Monday. Coincidentally, Monday also marked the 25 anniversary of the flyby of Neptune by Voyager 2.

“It’s a cosmic coincidence that connects one of NASA’s iconic past outer solar system explorers, with our next outer solar system explorer,” NASA Planetary Science Division Director said Jim Green remarked.

“Exactly 25 years ago at Neptune, Voyager 2 delivered our ‘first’ look at an unexplored planet. Now it will be New Horizons' turn to reveal the unexplored Pluto and its moons in stunning detail next summer on its way into the vast outer reaches of the solar system,” Green added.

Pluto, once designated a planet from the time of its discovery by astronomer Clyde Tombaugh in 1930, was changed to the designation of dwarf-planet in 2006 by the International Astronomical Union (IAU) after newer scientific data indicated that Pluto was a Kuiper belt object and that its properties did not fit the parameters of the definition of a planet.

The five known moons of Pluto are Charon, Hydra, Kerberos, Nix and Styx.

Due to its fairly elliptical orbit, occasionally Pluto’s orbital path crosses the orbital path of Neptune making it closer to the Sun than Neptune around the time of the dwarf-planet’s perihelion. The last time Pluto was closer to the Sun than Neptune was from 1979 to 1999 and it will not be closer to the Sun than Neptune again until the 23rd century.

New Horizons was launched in Jan. 2006 and will be mankind’s first close-up look at the frigid dwarf-planet and its satellites.