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  2. Timeline of artificial satellites and space probes - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_artificial...

    Mars Success: First deep space photographs of another planet and first flyby of Mars December 15 Italy: San Marco 1: Scout X-4: Earth Success: First Italian satellite (on American rocket) 1965 February 2 US: Ranger 8: Atlas-Agena: Moon Success: Lunar impactor. Returned pictures until impact. February 20 US: Ranger 9: Atlas-Agena: Moon Success ...

  3. Timeline of space exploration - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_space_exploration

    First communication between two crewed space vehicles in orbit. First person to float freely in microgravity. USSR Vostok 3 and Vostok 4: 18 August 1962 First auroral research rocket launched into the ionosphere. Norway: Ferdinand 1: November 1962: First Mars flyby (11,000 km) but contact was lost. USSR Mars 1: 14 December 1962

  4. Light-year - Wikipedia

    en.wikipedia.org/wiki/Light-year

    The product of Simon Newcomb's J1900.0 mean tropical year of 31 556 925.9747 ephemeris seconds and a speed of light of 299 792.5 km/s produced a light-year of 9.460 530 × 10 15 m (rounded to the seven significant digits in the speed of light) found in several modern sources [10] [11] [12] was probably derived from an old source such as C. W ...

  5. Timeline of Solar System exploration - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_Solar_System...

    First space station ... Mars 2: 19 May 1971 First Mars impact, Mars orbiter and attempted lander; First rover ... Lunar lander technology demonstration, lunar rover ...

  6. Chronology of the universe - Wikipedia

    en.wikipedia.org/wiki/Chronology_of_the_universe

    The spherical volume of space that will become the observable universe is 42 million light-years in radius at this time. The baryonic matter density at this time is about 500 million hydrogen and helium atoms per m 3, approximately a billion times higher than today. This density corresponds to pressure on the order of 10 −17 atm. Dark Ages

  7. Timeline of telescopes, observatories, and observing technology

    en.wikipedia.org/wiki/Timeline_of_telescopes...

    2007 – First light at Gran Telescopio de Canarias (GTC), in Spain, the largest optical telescope in the world with an effective diameter of 10.4 meters. 2021 — James Webb Space Telescope (JWST) , was launched 25 December 2021 on an ESA Ariane 5 rocket from Kourou, French Guiana and will succeed the Hubble Space Telescope as NASA's flagship ...

  8. Timeline of Solar System astronomy - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_Solar_System...

    The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun. The reform advanced the date by 10 days: Thursday 4 October 1582 was followed by Friday 15 ...

  9. Timeline of discovery of Solar System planets and their moons

    en.wikipedia.org/wiki/Timeline_of_discovery_of...

    The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery (multiple dates occur when the moments of imaging, observation, and publication differ), identified through its various designations (including temporary and permanent schemes), and the ...