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  2. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    An increase of 360° in the ERA is a full rotation of the Earth. A sidereal day on Earth is approximately 86164.0905 seconds (23 h 56 min 4.0905 s or 23.9344696 h). (Seconds are defined as per International System of Units and are not to be confused with ephemeris seconds.)

  3. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    It may also refer to the time it takes a satellite orbiting a planet or moon to complete one orbit. For celestial objects in general, the orbital period is determined by a 360° revolution of one body around its primary, e.g. Earth around the Sun. Periods in astronomy are expressed in units of time, usually hours, days

  4. Discovery of Neptune - Wikipedia

    en.wikipedia.org/wiki/Discovery_of_Neptune

    By 1846, the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path that could not be entirely explained by Newton's law of universal gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown ...

  5. Neptune - Wikipedia

    en.wikipedia.org/wiki/Neptune

    A size comparison of Neptune and Earth. Neptune's mass of 1.0243 × 10 26 kg [8] is intermediate between Earth and the larger gas giants: it is 17 times that of Earth but just 1/19th that of Jupiter. [g] Its gravity at 1 bar is 11.15 m/s 2, 1.14 times the surface gravity of Earth, [71] and surpassed only by Jupiter. [72]

  6. Neptune All Night - Wikipedia

    en.wikipedia.org/wiki/Neptune_All_Night

    Neptune All Night was a 9-hour TV program providing live coverage of the Voyager 2 space probe's flyby of the planet Neptune.The show, produced by the Philadelphia-area PBS affiliate WHYY-TV, was broadcast between midnight and 9:00 AM EDT on August 25, 1989, as Voyager 2 passed within 4,950 kilometres (3,080 mi) of the planet Neptune and within 40,000 kilometres (25,000 mi) of Neptune's ...

  7. Outline of Neptune - Wikipedia

    en.wikipedia.org/wiki/Outline_of_Neptune

    Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. [ a ] Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50 × 10 9 km).

  8. HD 110067 - Wikipedia

    en.wikipedia.org/wiki/HD_110067

    The six planets in the HD 110067 system are all smaller than Neptune, and revolve around their parent star in a very precise waltz: When the closest planet to the star makes three full revolutions around it, the second one makes exactly two during the same time; this is called a 3:2 resonance; the six planets form a resonant chain in pairs of 3 ...

  9. Exploration of Neptune - Wikipedia

    en.wikipedia.org/wiki/Exploration_of_Neptune

    The radio instruments on board found that Neptune's day lasts 16 hours and 6.7 minutes. Neptune's rings had been observed from Earth many years prior to Voyager 2 's visit, but the close inspection revealed that the ring systems were full circle and intact, and a total of four rings were counted. [4] Voyager 2 discovered six new small moons ...