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Date Event leading to space exploration Country Researcher(s) Ref(s). 1610 First telescopic observation of the night sky: discovery of the Galilean moons, lunar craters and the phases of Venus. Venice: Galileo Galilei: 1668 First reflecting telescope. England: Isaac Newton: 1781 First telescopic discovery of planet . Great Britain: William ...
Rubidium is the first alkali metal in the group to have a density higher than water. On Earth, natural rubidium comprises two isotopes: 72% is a stable isotope 85 Rb, and 28% is slightly radioactive 87 Rb, with a half-life of 48.8 billion years – more than three times as long as the estimated age of the universe.
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 ...
This is a timeline of Solar System exploration ordering events in the exploration of the Solar System by date of spacecraft launch. It includes: It includes: All spacecraft that have left Earth orbit for the purposes of Solar System exploration (or were launched with that intention but failed), including lunar probes .
(471325) 2011 KT 19, nicknamed Niku (/ n iː k uː /), is a trans-Neptunian object whose orbit is tilted 110° with respect to the planets' orbital plane.Thus, it has a nearly polar retrograde orbit around the Sun.
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 ...
The Hubble Space Telescope, the first large optical telescope in orbit, is launched using the Space Shuttle, but astronomers soon discovered that it is crippled by a problem with its mirror. A complex repair mission in 1993 allows the telescope to start producing spectacular images of distant stars, nebulae, and galaxies.
The first human being to reach space (defined as an altitude of over 100 km) and to orbit Earth was Yuri Gagarin, a Soviet cosmonaut who was launched in Vostok 1 on April 12, 1961. The first human to walk on the surface of another Solar System body was Neil Armstrong , who stepped onto the Moon on July 21, 1969 during the Apollo 11 mission ...