Here are a few interesting stories from the last week on cosmology, astronomy and the environment. Hope you enjoy (or are concerned as appropriate).
1. Clues to the Supernova that gave rise to the Solar System? From the New Yorker: Two tiny grains from two meteors may provide clues on the supernova that gave birth to the Solar System:
“The implication is that these two grains, in two meteorites, could have come from one supernova.
If this is the case, the supernova may have exploded close to the nebular region from which we formed some 4.6 billion years ago, and this could help explain our very origins. Astronomers have long conjectured that the “bump” of a supernova shock wave could have helped trigger the self-collapse of nebular gas and other dust that led to the formation of our solar system. (Like some giant hand squeezing the interstellar clay.) I
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With half-lives of around a million years, these radioactive nuclei provide a fierce boost to the heat in the interior of rocky bodies, from asteroids to the proto-planetary embryos of bigger objects. The molten innards of a planet form a mineral pressure cooker, ultimately leading to places like Earth, replete with volcanism and crusty plates of frozen rock afloat on a hot magma ocean.
Although it’s impossible to know how things would have played out in slightly different circumstances, we might owe that supernova a considerable debt. A less heated planet may have evolved differently, with less elemental recycling, or with some other kind of chemical makeup, and, perhaps, a very different environment for the growth of the complex carbon chemistry that led to living things.
All of which leaves us eyeing these two microscopic pieces of sand forged in the turbulent layers of a long-gone exploding stellar neighbor, and now embedded in a pair of polar meteorites. They’re not just a clue to what may have kick-started the formation of our solar system. They also hint at the source of the radioactively hot embers that helped warm our planets and set in motion life’s four-billion-year epic journey.”
2. Carbon Dioxide Level in Atmosphere Reaches Prehistoric Levels. From Scientific American:
“there is no question that the world continues to inexorably climb toward higher levels of greenhouse gas concentrations. Barring economic recessions, the world may be lucky to stop at 450, 500 or even beyond. Last year, humanity spewed some 36 billion metric tons of greenhouse gases, up from 35 billion the year before.”
3. Moon and Earth Have Common Water Source. From Science News:
“The Moon’s water did not come from comets but was already present on Earth 4.5 billion years ago, when a giant collision sent material from Earth to form the Moon.”
4. Exotic Atoms Hold Clues to Unsolved Physics Puzzle at the Dawn of the Universe. From Science News:
“The findings could advance the search for a new fundamental force in nature that could explain why the Big Bang created more matter than antimatter — a pivotal imbalance in the history of everything.”