Search results
Results From The WOW.Com Content Network
Strips cut from the striped part of the skin of an okapi, sent home by Sir Harry Johnston, were the first evidence of the okapi's existence to reach Europe.. Although the okapi was unknown to the Western world until the 20th century, it may have been depicted since the early fifth century BCE on the façade of the Apadana at Persepolis, a gift from the Ethiopian procession to the Achaemenid ...
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 ...
Counting them among the planets became increasingly cumbersome. Eventually, they were dropped from the planet list (as first suggested by Alexander von Humboldt in the early 1850s) and Herschel's coinage, "asteroids", gradually came into common use. [139] Since then, the region they occupy between Mars and Jupiter is known as the asteroid belt.
Its orbit revealed that it was a new planet, Uranus, the first ever discovered telescopically. [20] Giuseppe Piazzi discovered Ceres in 1801, a small world between Mars and Jupiter. It was considered another planet, but after subsequent discoveries of other small worlds in the same region, it and the others were eventually reclassified as ...
The term sol with a lowercase s is used by planetary astronomers for the duration of a solar day on another planet such as Mars. [21] The astronomical symbol for the Sun is a circle with a center dot, . [22] It is used for such units as M ☉ , R ☉ (Solar radius) and L ☉ (Solar luminosity).
Friedrich Bessel successfully uses the method of stellar parallax, the effect of Earth's annual movement around the Sun, to calculate the distance to 61 Cygni, the first star other than the Sun to have its distance from Earth measured. Bessel's is a truly accurate measurement of stellar positions, and the parallax technique establishes a ...
Aristarchus of Samos (/ ˌ æ r ə ˈ s t ɑːr k ə s /; Ancient Greek: Ἀρίσταρχος ὁ Σάμιος, Aristarkhos ho Samios; c. 310 – c. 230 BC) was an ancient Greek astronomer and mathematician who presented the first known heliocentric model that placed the Sun at the center of the universe, with the Earth revolving around the Sun once a year and rotating about its axis once a day.
For the outer planets, the angle between the center of the epicycle and the planet was the same as the angle between the Earth and the Sun. Ptolemy did not predict the relative sizes of the planetary deferents in the Almagest. All of his calculations were done with respect to a normalized deferent, considering a single case at a time.