Category Archives: Outer Proto-Earths

Chemistry of Saturn’s moon Enceladus Matches Earth’s Ocean Origins

….”That’s an important question: while Earth has a lot of water on its surface today, that hasn’t always been the case. After it formed, our planet had a surface of molten rock when any liquid water would boil away; that period of time is known as the Hadean Eon for its hellish character. While Earth’s deep interior has a lot of water in it, that’s mostly trapped in the crystal structure of minerals rather than in giant underground reservoirs, so it’s unlikely the oceans were entirely fed by water bubbling up from below. That leaves another possibility: maybe Earth’s water came from space. After the Hadean Eon, Earth was bombarded by meteoroids (small asteroids) and comets, which might have brought enough water with them to make the oceans. That’s why comets especially look promising: they contain a lot of water ice, while it would take a lot more meteoroids to.
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Proof Mars Was Once Like Io

“There are only around 100 Martian meteorites in collections around the world, according to BBC News, but almost all of them are much younger than Black Beauty – dating from around 150 to 600 million years ago. Scientists were able to analyse the different minerals encased in the 7553 fragment – one of five found in the desert – and said it showed the volatile nature of Mars’ surface. “It contains zircons for which we measured an age of 4,428 ± 25 million years, which were later disturbed 1,712 ± 85 million years ago,” Prof Humayan wrote. He explained: “The crust of Mars must have differentiated really quickly, rather than gradually over time. There was a big volcanic episode all over the surface, which then crusted up, and after that the volcanism dropped dramatically.” Source: http://www.independent.co.uk    .
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New Proof Ganymede Was Once Europa

  “Ganymede’s period of geologic activity should have ended by∼4Ga(e.g.Reynolds and Cassen, 1979; Schubert et al., 1981; Friedson and Stevenson, 1983; Kirk and Stevenson, 1987).”   Patterson, Wesley; Head, James W.; et al. (2007). “A Global Geologic Map of Ganymede” (PDF). Lunar and Planetary Science. XXXVIII: 1098. ——— “Recent ground-based observations of the Galilean moons and analysis of historical data suggest that the satellites evolve out of resonance, implying that Ganymede is receding from Jupiter (Lainey et al., 2009).” http://www.lpi.usra.edu/decadal/opag/GanymedeScience.pdf ——— “While the simulations described above produce conditions favorable to resurfacing Ganymede, the surface area expansion that results from remelting a differentiated satellite is less than half of the strains measured on the surface. We therefore may require an alternative mechanism capable of explaining both the timing and magnitude of Ganymede’s global expansion. A potential scenario for such expansion stems from the possibility that both Ganymede and Callisto formed undifferentiated.
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Raisin’ mountains on Saturn’s moon Titan

This mosaic, made from radar images obtained by NASA’s Cassini spacecraft, shows mountainous terrain on Saturn’s moon Titan in the moon’s northern hemisphere, north of the Aaru region. Image credit: NASA/JPL-Caltech   Saturn’s moon Titan ripples with mountains, and scientists have been trying to figure out how they form. The best explanation, it turns out, is that Titan is shrinking as it cools, wrinkling up the moon’s surface like a raisin. A new model developed by scientists working with radar data obtained by NASA’s Cassini spacecraft shows that differing densities in the outermost layers of Titan can account for the unusual surface behavior. Titan is slowly cooling because it is releasing heat from its original formation and radioactive isotopes are decaying in the interior. As this happens, parts of Titan’s subsurface ocean freeze over, the outermost ice crust thickens and folds, and the moon shrivels up. The model is described.
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Cassini locates Titan’s tallest peaks

The trio of ridges on Titan known as Mithrim Montes is home to the hazy Saturnian moon’s tallest peak. Credit: NASA/JPL-Caltech/ASI   In a nod to extraterrestrial mountaineers of the future, scientists working on NASA’s Cassini mission have identified the highest point on Saturn’s largest moon, Titan. Titan’s tallest peak is 10,948 feet (3,337 meters) high and is found within a trio of mountainous ridges called the Mithrim Montes. The researchers found that all of Titan’s highest peaks are about 10,000 feet (3,000 meters) in elevation. The study used images and other data from Cassini’s radar instrument, which can peer through the obscuring smog of Titan’s atmosphere to reveal the surface in detail. “It’s not only the highest point we’ve found so far on Titan, but we think it’s the highest point we’re likely to find,” said Stephen Wall, deputy lead of the Cassini radar team at NASA’s Jet Propulsion.
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