Search results
Results from the WOW.Com Content Network
In celestial mechanics, a Kepler orbit (or Keplerian orbit, named after the German astronomer Johannes Kepler) is the motion of one body relative to another, as an ellipse, parabola, or hyperbola, which forms a two-dimensional orbital plane in three-dimensional space. A Kepler orbit can also form a straight line.
Osculating orbit is the temporary Keplerian orbit about a central body that an object would continue on, if other perturbations were not present. Retrograde motion is orbital motion in a system, such as a planet and its satellites, that is contrary to the direction of rotation of the central body, or more generally contrary in direction to the ...
c. 475 BCE – Parmenides is credited to be the first Greek who declared that the Earth is spherical and is situated in the centre of the universe, believed to have been the first to detect the identity of Hesperus, the evening-star, and Phosphorus, the morning-star (Venus), [13] and by some, the first to claim that moonlight is a reflection of ...
Ancient Greek astronomy can be divided into three primary phases: Classical Greek Astronomy, which encompassed the 5th and 4th centuries BC, and Hellenistic Astronomy, which encompasses the subsequent period until the formation of the Roman Empire ca. 30 BC, and finally Greco-Roman astronomy, which refers to the continuation of the tradition 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 ...
Kepler's first law states that: The orbit of every planet is an ellipse with the sun at one of the two foci. Kepler's first law placing the Sun at one of the foci of an elliptical orbit Heliocentric coordinate system (r, θ) for ellipse.
When moving away from the source it is called an escape orbit, otherwise a capture orbit. It is also sometimes referred to as a C 3 = 0 orbit (see Characteristic energy ). Under standard assumptions a body traveling along an escape orbit will coast along a parabolic trajectory to infinity, with velocity relative to the central body tending to ...
In the Hipparchian, Ptolemaic, and Copernican systems of astronomy, the epicycle (from Ancient Greek ἐπίκυκλος (epíkuklos) 'upon the circle', meaning "circle moving on another circle") [1] was a geometric model used to explain the variations in speed and direction of the apparent motion of the Moon, Sun, and planets.