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Modern Space Exploration: Neptune

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Neptune

                                                             

Neptune Articles

Significant Events

  • 1612: Galileo incorrectly records Neptune as a fixed star during observations with his small telescope.

  • 1846: Using mathematical calculations, astronomers discover Neptune, increasing the number of known planets to eight. Neptune's largest moon, Triton, is found the same year.

  • 1983: Pioneer 10 crosses the orbit of Neptune and becomes the first human-made object to travel beyond the orbits of the planets of our solar system. The spacecraft remains on a trajectory heading towards the red star Aldebaran (in the constellation Taurus) and is expected to pass by it in about 2,000,000 years.

  • 1984: Astronomers find evidence for the existence of a ring system around Neptune.

  • 1989: Voyager 2 becomes the first and only spacecraft to visit Neptune, passing about 4,800 kilometers (2,983 miles) above the planet's north pole.

  • 2002: Using improved observing techniques, astronomers discover four new moons orbiting Neptune: Laomedia, Neso, Sao and Halimede.

  • 2003: Another moon, Psamathe, is discovered using ground-based telescopes.

  • 2005: Scientists using the Keck Observatory take images of the outer rings and find that some of the ring arcs have deteriorated.

  • 2011: Neptune completes its first 165-year orbit of the sun since its discovery in 1846.

  • 2013: A scientist studying Neptune's ring arcs in archival Hubble Space Telescope images finds a previously unknown 14th moon of Neptune, provisionally designated S/2004 N 1.

  • 2016: Scientists using the Hubble Space Telescope discover a new dark spot on Neptune, the first new atmospheric vortex seen in the 21st century.

“Exploration.” NASA, NASA, 26 June 2019, solarsystem.nasa.gov/planets/neptune/exploration/?

 

Neptune Quick Facts

Quick Facts

Day
16 hours

Year
165 Earth years

Radius
15,299.4 miles | 24,622 kilometers

Planet Type
Ice Giant

Moons
14

“In Depth.” NASA, NASA, 23 June 2020, solarsystem.nasa.gov/planets/neptune/in-depth/.