| Piú viste - The Universe Inside |
Earth__Impact_Craters_-_Acraman_Crater_-_Australia.jpgAcraman Crater (Australia)141 visiteCreato dall'impatto di un asteroide 590 milioni di anni fa, il cratere Acraman (Dia. 40 Km c.a.) nella Australia meridionale e' definito dal lago Acraman.MareKromium
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lake_of_the_sun_1600.jpgDeep Thoughts140 visite
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Moonlight.jpgDistortions... (Image Credit & Copyright: Giacomo Venturin)140 visite"...L'usanza comune a molti letterati di disprezzare il mondo moderno e' una maniera dissimulata di presumersi degni di un altro migliore..."
Aristide GabelliMareKromium
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FreeFall-1.jpgFree-Fall138 visiteDa "NASA - Picture of the Day" del 20.02.2006:"...Like a scene from a space mystery movie, a spacesuit floated away from the International Space Station earlier this month, but no investigation was needed. It was pushed out by the space station crew. Dubbed Suitsat-1, the unneeded Russian Orlan spacesuit filled mostly with old clothes was fitted with a faint radio transmitter and released to orbit the Earth. Suitsat-1 will orbit once every 90 minutes until it burns up in the Earth's atmosphere within a few weeks. The suit circled the Earth twice before its radio signal became unexpectedly weak. Pictured above, the lifeless spacesuit was photographed as it drifted away from the Earth-orbiting space station earlier this month..."
Nota: anche se la caption originale NASA si guarda bene dal dirlo, non siamo davanti nè ad uno scherzo, nè ad un gioco, ovviamente.
Questo esperimento, come in molti avranno già capito, è stato effettuato al solo scopo di vedere che cosa accadrebbe (e, di conseguenza, come si potrebbe intervenire) qualora un Astronauta "sfuggisse" agli ormeggi e si allontanasse - irreversibilmente - dalla Stazione Spaziale Internazionale.
Conseguenze a breve: l'Astronauta diventa un "satellite" ed inizia ad orbitare.
Nel tempo (esaurimento delle scorte di O2 a parte), questo "satellite umano" inizia a perdere quota e poi finisce con l'avviare una vera e propria "fase di rientro".
Ma l'Astronauta non è una Navicella Spaziale dotata di schermature protettive: il rientro, ovviamente, non si compirebbe mai ed il malcapitato Astronauta finirebbe bruciato (vivo o morto, ma presumibilmente morto) già negli strati superiori dell'atmosfera (ricordate il film "Mission to Mars"?).
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Sundogs.jpgThe "Sundogs", again137 visiteCaption NASA originale da "NASA - Picture of the Day" del 23 Agosto 1999 :"What if you woke up one morning and saw more than one Sun in the sky? Most probably, you would be seeing Sundogs, extra-images of the Sun created by falling ice-crystals in the Earth's atmosphere. As water freezes in the atmosphere, small, flat, six-sided, ice crystals might be formed. As these crystals flutter to the ground, much time is spent with their faces flat, parallel to the ground. An observer may pass through the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our view and creating parhelia, the technical term for sundogs. Sundogs were photographed here in a cloudy sky above the Very Large Array of radio telescopes. A bright Sundog is visible on the far right, and a dim one on the far left. Ice-crystals can create other strange illusions of the Sun and Moon including halos and pillars".
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BlackSun in Antarctica.jpgBlack Sun in Antarctica (November 2003)137 visitenessun commento
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Equinox.jpgEquinox137 visite
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thermal_trenches_1600.jpgUncommon Mistake137 visite
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Solar_Eclipse~2.jpgFeeding on the Sun...137 visite"Essere immortale è cosa da poco: tranne l'uomo, infatti, tutte le Creature lo sono, giacché ignorano la Morte. Ma la cosa Divina, Terribile ed Incomprensibile, è nel sapersi immortali..."
Jorge Luis BorgesMareKromium
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Dark_Matter~0.jpgDark Matter136 visiteDark matter is a form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total mass–energy density or about 2.241×108722,27 kg/m3. Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained by accepted theories of gravity unless more matter is present than can be seen. For this reason, most experts think that dark matter is abundant in the universe and that it has had a strong influence on its structure and evolution. Dark matter is called dark because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect or emit electromagnetic radiation, and is therefore difficult to detect.
Primary evidence for dark matter comes from calculations showing that many galaxies would fly apart, or that they would not have formed or would not move as they do, if they did not contain a large amount of unseen matter. Other lines of evidence include observations in gravitational lensing and in the cosmic microwave background, along with astronomical observations of the observable universe's current structure, the formation and evolution of galaxies, mass location during galactic collisions and the motion of galaxies within galaxy clusters. In the standard Lambda-CDM model of cosmology, the total mass–energy of the universe contains 5% ordinary matter and energy, 27% dark matter and 68% of a form of energy known as dark energy. Thus, dark matter constitutes 85% of total mass, while dark energy plus dark matter constitute 95% of total mass–energy content.
Because dark matter has not yet been observed directly, if it exists, it must barely interact with ordinary baryonic matter and radiation, except through gravity. Most dark matter is thought to be non-baryonic in nature; it may be composed of some as-yet undiscovered subatomic particles. MareKromium
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Earth_Impact_Craters_-_Gosses_Bluff_Crater_-_Australia.jpgGosses Bluff Crater (Australia)136 visiteSituato nel Northern Territory meridionale, l'imponente cratere meteorico Gosses Bluff ha un diametro di 5 km e un'altezza del bordo di 200 metri. Il sito e' noto come Tnorala agli aborigeni occidentali di Arrernte ed e' un luogo sacro.MareKromium
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Earth_Impact_Craters_-_Kaali_Crater_-_Estonia.jpgKaali Crater (Eastland)136 visiteKaali e' il nome collettivo di un gruppo di nove laghi di crateri meteoritici nel villaggio di Kaali, sull'isola estone di Saaremaa. La formazione dell'ammasso e' datata poco dopo il 1530-1450 a.C.MareKromium
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