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Hubble Finds Oxygen Atmosphere On Jupiter's Moon Europa . Astronomers using NASA's Hubble Space Telescope (HST) have identified the presence of an extremely tenuous atmosphere of molecular oxygen around Jupiter's second moon, Europa . ... Europa's oxygen atmosphere is so tenuous that its surface pressure is barely one hundred billionth that of the Earth," said Principal Investigator Doyle Hall, of Johns Hopkins. ... The oxygen gas slowly leaks into space and must be replenished continuously. ...

Deep Time: Earth's history and future By Colin Johnston, Armagh Planetarium Earth 4.54 billion years ago Forms in Sun's protoplanetary disc S un Elsewhere in Solar System Other planets form. ... Hot and airless Sun a subgiant, diameter 1.5 its current value, 2 6.4 billion years from no w ? ... Earth cools 20 million years later? ... Core temperature about 55 million°C, helium flash, followed by the Sun shrinking Sun is 10 times its current diameter, luminosity 20-50% current value. ...

... Uranus: The Tilted Planet . ... Uranus is the third largest planet in our Solar System after Jupiter and Saturn. Uranus is composed mostly of rock and ices, but with a thick hydrogen and helium atmosphere. ... Pioneer 10: The First 7 Billion Miles . ... Shown in this stunning false-color Hubble Space Telescope image, the galaxy's disk - composed of spectacular star clusters in winding spiral arms and dramatic dark lanes of dust - spans some 70,000 light-years. Dark Spots on Neptune . ...

... i.e., the interaction of light (generally from the sun or moon) with stuff in the air: molecules, water: ice and drops; crud; smoke.. ... Ice crystals: halos, sun pillars: the whiteness and brightness of snow . ... What to look for: common halos; coloured and white structures; symmetry and asymmetry . ... How crystals float in the air; the specific orientations mean that some halos change shape and position as the sun changes altitude . ... What do halos look like and how do we recognise them? ...

... These electrons may be free or bound to an atom or ion. ... The modelling of a stellar atmospheres (or any astrophysical object) and its emergent radiation requires a detailed model of how photons interact with electrons. ... These "atomic data" are fundamental to accurate astrophysical modelling. ... For calculating model spectra of early-type helium stars in LTE, I maintain a database of atomic data for, mostly, blue-visual absorption lines of light elements. ... Simon's home page . ...

... Detectability of CO, PH3, AsH3, and GeH4 in the Atmosphere of Gl 229B . ... Missions . ... Future Missions and . ... Missions Office . ... Research . Research Staff Directory . Journal Clubs and Research Groups . ... In this work, we show calculated spectra using a model atmosphere for Gl 229B and high-resolution, line-by-line radiative transfer code including molecular hydrogen collision-induced opacity and molecular line absorption from H2O, CO, PH3, GeH4, and AsH3. ...

. If this velocity is comparable to the escape velocity, then molecules of this type can escape into space. Thus the condition for escape is: . Previous slide . Next slide . Back to first slide . View graphic version .