Search results
Results from the WOW.Com Content Network
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 ...
Mercury, the smallest and innermost planet, has no moons, or at least none that can be detected to a diameter of 1.6 km (1.0 mi). [2] For a very short time in 1974, Mercury was thought to have a moon. Venus also has no moons, [3] though reports of a moon around Venus have circulated since the 17th century.
Consequently, Venus transits only occur when an inferior conjunction takes place during some days of June or December, when the orbits of Venus and Earth cross a straight line with the Sun. [189] This results in Venus transiting above Earth in a sequence currently of 8 years, 105.5 years, 8 years and 121.5 years, forming cycles of 243 years.
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 ...
In the Dresden Codex, the Maya included an almanac showing Venus's full cycle, in five sets of 584 days each (approximately eight years), after which the patterns repeated (since Venus has a synodic period of 583.92 days). [12] The Maya were aware of this synodic period, and could compute it to within a hundredth part of a day. [11]
Venus was 0.7205 au from the Sun on the day of transit, decidedly less than average. [ 9 ] Moving far backwards in time, more than 200,000 years ago Venus sometimes passed by at a distance from Earth of barely less than 38 million km, and will next do that after more than 400,000 years.
The moons of the trans-Neptunian objects (other than Charon) have not been included, because they appear to follow the normal situation for TNOs rather than the moons of Saturn and Uranus, and become solid at a larger size (900–1000 km diameter, rather than 400 km as for the moons of Saturn and Uranus).
In astronomy, an octaeteris (Greek: ὀκταετηρίς, plural: octaeterides) is the period of eight solar years after which the moon phase occurs on the same day of the year plus one or two days. This period is also in a very good synchronicity with five Venusian visibility cycles (the Venusian synodic period ) and thirteen Venusian ...