* Astronomy

Blobrana · L

RE: Solar System formation

Blobrana · L

Comet dust reveals unexpected mixing of solar system
Chemical clues from a comet's halo are challenging common views about the history and evolution of the solar system and showing it may be more mixed-up than previously thought.
A new analysis of dust from the comet Wild 2, collected in 2004 by NASA's Stardust mission, has revealed an oxygen isotope signature that suggests an unexpected mingling of rocky material between the center and edges of the solar system. Despite the comet's birth in the icy reaches of outer space beyond Pluto, tiny crystals collected from its halo appear to have been forged in the hotter interior, much closer to the sun.

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New Clues to Oxygen at the Origin of the Solar System
Oxygen is the most abundant element on Earth, accounting for almost half the planet's mass. Of its three stable isotopes, oxygen 16 makes up 99.762 percent of oxygen on Earth, while heavier oxygen 17 accounts for just 0.038 percent, and the heaviest isotope, oxygen 18, makes up 0.2 percent. Yet minerals in some of the most primitive objects in the solar system, including the meteorites called carbonaceous chondrites, have quite different ratios of oxygen isotopes than on Earth; presumably the rare heavy isotopes occurred in much greater abundances in the early solar system.

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Title: Gas disks to gas giants: Simulating the birth of planetary systems
Authors: Edward W. Thommes, Soko Matsumura, Frederic A. Rasio

The ensemble of now more than 250 discovered planetary systems displays a wide range of masses, orbits and, in multiple systems, dynamical interactions. These represent the end point of a complex sequence of events, wherein an entire protostellar disk converts itself into a small number of planetary bodies. Here, we present self-consistent numerical simulations of this process, which produce results in agreement with some of the key trends observed in the properties of the exoplanets. Analogues to our own solar system do not appear to be common, originating from disks near the boundary between barren and (giant) planet-forming.

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Blobrana · L

We don't have spacecraft to take us outside our solar system--not yet, at least. Still, astronomers thought they had a pretty good understanding of how our solar system formed and in turn, how others formed. In the last dozen years, nearly 300 exoplanets have been discovered. Are the solar systems in which they reside indeed like our own? Without knowledge or observations to the contrary, conventional knowledge said yes. Three Northwestern University researchers questioned that assumption and explored this question. What they learned is that the solar system in which the Earth orbits our sun is actually uncommon.

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Higher than expected levels of sodium found in a 4.6 billion-year-old meteorite (Semarkona meteorite) suggest that the dust clouds from which the building blocks of the Earth and neighbouring planets formed were much denser than previously supposed. The study, by scientists from the Carnegie Institution, American Museum of Natural History, and U.S. Geological Survey, is published in the June 20 issue of Science.

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Astronomers searching for distant supernovae to probe dark energy in the early universe have unwittingly stumbled upon two relatively nearby objects that may shed light on the early solar system.
One (2003 UC414) lies in a nearly circular orbit between Uranus and Neptune, while the other (2004 VN112) may have been kicked out to a much more distant, tilted orbit by a marauding planet that was lost to the solar system long ago.

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First, the bad news: the inner solar system is unstable. Given enough time, Jupiter's gravity could yank Mercury out of its present orbit.
Two new computer simulations of long-term planetary motion one by Jacques Laskar (Paris Observatory), the other by Konstantin Batygin and Gregory Laughlin (University of California, Santa Cruz) have both reached the same disturbing conclusion.
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A new study is challenging the long-standing notion that the whole solar system formed from the same raw materials.
Until now most scientists had believed that the inner solar system bodiesMercury, Venus, Earth, its moon, and Marshad the same composition as primitive meteorites called chondrites.
But, problematically, Earth's chemistry doesn't quite match.
Now, French researcher Guillaume Caro, from Centre de Recherches Pétrographiques et Géochimiques in France, and his colleagues say that the makeup of Mars and the moon don't correspond either.
It turns out the three bodies may be more similar to each other than the chondrite-rich asteroids located between Mars and Jupiter.

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The.Outer.Planets

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