Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results.
Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets. (Full article...)
The following are images from various astronomy-related articles on Wikipedia.
Image 1Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 5Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 6Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 22Portrait of the Flemish astronomer Ferdinand Verbiest who became head of the Mathematical Board and director of the Observatory of the Chinese emperor in 1669 (from Astronomer)
Image 23An image of the Cat's Paw Nebula created combining the work of professional and amateur astronomers. The image is the combination of the 2.2-metre MPG/ESO telescope of the La Silla Observatory in Chile and a 0.4-meter amateur telescope. (from Amateur astronomy)
Image 25An example of a gravitational lens found in the DESI Legacy Surveys data. There are four sets of lensed images in DESI-090.9854-35.9683, corresponding to four distinct background galaxies—from the outermost giant red arc to the innermost bright blue arc, arranged in four concentric circles. All of them are gravitationally warped—or lensed—by the orange galaxy at the very center. Dark matter is expected to produce gravitational lensing also. (from Physical cosmology)
Image 28ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 29An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 31Artist conception of the Big Bang cosmological model, the most widely accepted out of all in physical cosmology (neither time nor size to scale) (from Physical cosmology)
Image 32The inflationary theory as an augmentation to the Big Bang theory was first proposed by Alan Guth of MIT. Inflation solves the 'horizon problem' by making the early universe much more compact than was assumed in the standard model. Given such smaller size, causal contact (i.e., thermal communication) would have been possible among all regions of the early universe. The image was an adaptation from various generic charts depicting the growth of the size of the observable universe, for both the standard model and inflationary model respectively, of the Big Bang theory. (from Physical cosmology)
Image 37Segment of the astronomical ceiling of Senenmut's Tomb (circa 1479–1458 BC), depicting constellations, protective deities, and twenty-four segmented wheels for the hours of the day and the months of the year (from History of astronomy)
This is a Featured article, which represents some of the best content on English Wikipedia.
Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet, having the closest orbit and the most similar mass and size to Earth among the planets of the Solar System. Both are rocky planets, but Venus lacks liquid water and has an atmosphere of mostly carbon dioxide (CO2), with a global sulfuric acid cloud cover. The atmosphere is significantly thicker and denser than Earth's and any other rocky planet in the Solar System. At the average surface level, the atmosphere reaches a temperature of 737 K (464 °C; 867 °F) and a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the carbon dioxide atmosphere into a supercritical fluid.
Venus is the third brightest object in Earth's sky, after the Moon and the Sun, and, like Mercury, always appears relatively close to the Sun, either as a "morning star" or an "evening star", resulting from orbiting closer (inferior) to the Sun than Earth.
While the orbit of Venus is the closest to Earth's, the most inferior orbiting Mercury stays for a longer time closer to all the superior orbiting planets, Venus and Earth approaching each other in synodic periods of 1.6 years. Venus though is the planet with the lowest delta-v needed to travel to from Earth, and is therefore often used for gravity assists and as a common waypoint for interplanetary flights from Earth.
A Venusian day is 116.75 Earth days long, about half a Venusian solar year, which is 224.7 Earth days long. The rotation of Venus has been slowed and turned against its orbital direction (retrograde) by the currents and drag of its atmosphere. (Full article...)
_(cropped).jpg)
.jpg)
.jpg)
_(cropped).jpg)
.jpg)
Commons
Wikibooks
Wikidata
Wikinews
Wikiquote
Wikisource
Wikiversity
Wiktionary
