Astronomy picture of the day - 2016 December 8 - Whirlpool with Comets

Whirlpool with Comets 
Image Credit & Copyright: José J. Chambó (Cometografia)

Explanation: Not a comet, bright spiral galaxy Messier 51 is popularly known as the Whirlpool Galaxy. Just off the handle of the Big Dipper in northern skies, you can spot it at the upper left in this image from December 1st. The pretty 4 by 2.5 degree wide field of view does contain two comets though. Different in appearance, both comets are new visitors to the inner Solar System and are currently faint telescopic objects, highest above northern horizons in morning twilight. At lower left newly discovered comet NEOWISE (C/2016 U1) shows off a round fuzzy coma in the greenish light of diatomic carbon gas fluorescing in sunlight. Sunlight reflects from dust in the coma and stubby tail of comet Johnson (C/2015 V2) at upper right.

Expressões populares portuguesas - Fazer tabua rasa

Significado: Esquecer completamente um assunto para recomeçar em novas bases. 

Origem: A tabula rasa , no latim, correspondia a uma tabuinha de cera onde nada estava escrito. A expressão foi tirada, pelos empiristas, de Aristóteles, para assim chamarem ao estado do espírito que, antes de qualquer experiência, estaria, em sua opinião, completamente vazio. Também John Locke (1632 1704), pensador inglês, em oposição a Leibniz e Descartes, partidários do inatísmo, afirmava que o homem não tem nem ideias nem princípios inatos, mas sim que os extrai da vida, da experiência. «Ao começo», dizia Locke, «a nossa alma é como uma tábua rasa, limpa de qualquer letra e sem ideia nenhuma. Tabula rasa in qua nihil scriptum. Como adquire, então, as ideias? Muito simplesmente pela experiência.»

Eric Clapton - "Wonderful tonight" - Video - Music - Live

"Wonderful tonight"

Palacios cariocas - Câmara Municipal de Niterói

Localizada Praça da República, em Niterói, a Câmara Municipal faz parte do Centro Cívico juntamente com a Delegacia, o Fórum, o Liceu e a Biblioteca Estadual.

Aqui funcionou entre os anos de 1917 e 1975 o Palácio da Assembleia Legislativa do Estado do Rio de Janeiro, quando Niterói era a capital do estado.

Atualmente abriga diversas exposições e o arquivo público.

Astronomy picture of the day - 2016 December 7 - NGC 4696: Filaments around a Black Hole

NGC 4696: Filaments around a Black Hole 
Image Credit: NASA, ESA, Hubble, A. Fabian

Explanation: What's happening at the center of elliptical galaxy NGC 4696? There, long tendrils of gas and dust have been imaged in great detail as shown by this recently released image from the Hubble Space Telescope. These filaments appear to connect to the central region of the galaxy, a region thought occupied by a supermassive black hole. Speculation holds that this black hole pumps out energy that heats surrounding gas, pushes out cooler filaments of gas and dust, and shuts down star formation. Balanced by magnetic fields, these filaments then appear to spiral back in toward and eventually circle the central black hole. NGC 4696 is the largest galaxy in the Centaurus Cluster of Galaxies, located about 150 million light years from Earth. The featured image shows a region about 45,000 light years across.

Astronomy picture of the day - 2016 December 6 - Aurora over Jupiter's South Pole from Juno

Aurora over Jupiter's South Pole from Juno 
Image Credit: NASA, JPL-Caltech, SwRI, ASI, INAF, JIRAM

Explanation: Why is there a glowing oval over Jupiter's South Pole? Aurora. Near the closest part of its first pass near Jupiter in August, NASA's robotic spacecraft Juno captured this dramatic infrared image of a bright auroral ring. Auroras are caused by high energy particles from the Sun interacting with a planet's magnetic field, and ovals around magnetic poles are common. Data from Juno are giving preliminary indications that Jupiter's magnetic field and aurorae are unexpectedly powerful and complex. Unfortunately, a computer glitch caused Juno to go into safe mode during its last pass near the Jovian giant in September. That glitch has now been resolved, making Juno ready for its next pass over Jupiter's cloud tops this coming Sunday.

Astronomy picture of the day - 2016 December 5 - Lightning over Colorado

Lightning over Colorado 
Image Credit & Copyright: Joe Randall

Explanation: Have you ever watched a lightning storm in awe? Join the crowd. Oddly, nobody knows exactly how lightning is produced. What is known is that charges slowly separate in some clouds causing rapid electrical discharges (lightning), but how electrical charges get separated in clouds remains a topic of much research. Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun. The resulting shock wave starts supersonically and decays into the loud sound known as thunder. Lightning bolts are common in clouds during rainstorms, and on average 44 lightning bolts occur on the Earth every second. Pictured, over 60 images were stacked to capture the flow of lightning-producing storm clouds in July over Colorado Springs, Colorado, USA.

Astronomy picture of the day - 2016 December 4 - Orion and Official Star Names

Orion and Official Star Names 
Image Credit & Copyright: Rogelio Bernal Andreo

Explanation: Familiar stars in Orion and constellations across the sky now have official names. Over the past year, the International Astronomical Union, the only body officially tasked with naming stars, approved names already in common use for 227 of the brightest stars, including the most famous stars on the sky Sirius, Polaris, and Betelgeuse. Pictured, the constellation of Orion is shown with several of these now-official star names superposed. Spanning about 30 degrees, this breath-taking vista stretches across the well-known constellation from head to toe (left to right) and beyond. The common names for all three stars in Orion's belt are also now official. At 1,500 light years away, the Great Orion Nebula is the closest large star forming region, here visible just right and below center. Also visible are famous nebulae including the Horsehead Nebula and the Witch Head Nebula. Of course, the Orion Nebula and bright stars are easy to see with the unaided eye, but dust clouds and emission from the extensive interstellar gas in this nebula-rich complex, are too faint and much harder to record. In the featured mosaic of broadband telescopic images, additional image data acquired with a narrow hydrogen alpha filter was used to bring out the pervasive tendrils of energized atomic hydrogen gas like in the arc of the giant Barnard's Loop.

Astronomy picture of the day - 2016 December 3 - Galaxies in Pegasus

Galaxies in Pegasus 
Image Credit & Copyright: Péter Feltóti

Explanation: This wide, sharp telescopic view reveals galaxies scattered beyond the stars of the Milky Way at the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan's Quintet. About 300 million light-years distant, the quintet dramatically illustrates a multiple galaxy collision, its powerful, ongoing interactions posed for a brief cosmic snapshot. On the sky, the quintet and NGC 7331 are separated by about half a degree.

Astronomy picture of the day - 2016 December 2 - A Triple Star is Born

A Triple Star is Born 
Image Credit: Bill Saxton, ALMA (ESO/NAOJ/NRAO), NRAO/AUI/NSF - Publication: John Tobin (Univ. Oklahoma/Leiden) et al.

Explanation: A triple star system is forming, enshrouded within this dusty natal disk some 750 light-years away in the Perseus molecular cloud. Imaged at millimeter wavelengths by the Atacama Large Millimeter/submillimeter Array(ALMA) in Chile, the extreme close-up shows two protostars separated by a mere 61 AU (1 AU is the Earth-Sun distance) with a a third some 183 AU from the central protostar. The ALMA image also reveals a clear spiral structure indicating instability and fragmentation led to the multiple protostellar objects within the disk. Astronomers estimate that the system, cataloged as L1448 IRS3B, is less than 150,000 years old. Captured at an early phase, the starforming scenario is likely not at all uncommon, since almost half of all sun-like stars have at least one companion.