Group items tagged predictions - Astronomy

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Earth's magnetic field has flipped - 0 views

shared by Astro Biology on 20 Oct 14 - No Cached

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[0806.0377] A Hemispherical Power Asymmetry from Inflation - 0 views

arxiv.org/0806.0377 astronomy astrophysics observatory physics

shared by Todd Suomela on 13 Jun 08 - Cached

Todd Suomela on 13 Jun 08

Measurements of temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry cannot be generated during single-field slow-roll inflation without violating constraints to the homogeneity of the Universe. In contrast, a multi-field inflationary theory, the curvaton model, can produce this power asymmetry without violating the homogeneity constraint. The mechanism requires the introduction of a large-amplitude superhorizon perturbation to the curvaton field, possibly a pre-inflationary remnant or a superhorizon curvaton-web structure. The model makes several predictions, including non-Gaussianity and modifications to the inflationary consistency relation, that will be tested with forthcoming CMB experiments.

<div class="cArrow"> </div><div class="cContentInner">Measurements of temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry cannot be generated during single-field slow-roll inflation without violating constraints to the homogeneity of the Universe. In contrast, a multi-field inflationary theory, the curvaton model, can produce this power asymmetry without violating the homogeneity constraint. The mechanism requires the introduction of a large-amplitude superhorizon perturbation to the curvaton field, possibly a pre-inflationary remnant or a superhorizon curvaton-web structure. The model makes several predictions, including non-Gaussianity and modifications to the inflationary consistency relation, that will be tested with forthcoming CMB experiments.</div>

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Study plunges standard Theory of Cosmology into Crisis - 0 views

www.physorg.com/print160726282.html Astrophysics

shared by Maluvia Haseltine on 25 Jul 09 - Cached

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[0904.0402] A thermodynamic basis for prebiotic amino acid synthesis and the nature of ... - 0 views

arxiv.org/0904.0402 arxiv astrobiology exobiology astronomy biology

shared by Todd Suomela on 07 Apr 09 - Cached

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Todd Suomela on 07 Apr 09

Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these ten early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.

<div class="cArrow"> </div><div class="cContentInner">Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these ten early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal. </div>

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Einstein's Theory of General Relativity - 0 views

www.space.com/theory-general-relativity.html astronomy science space universe planetary solar galactic astrophysics Physics

shared by hanz444 on 22 Sep 15 - No Cached

Time Will End in Five Billion Years, Physicists Predict - 2 views

news.nationalgeographic.com/...d-of-time-multiverse-inflation Astronomy

shared by Kalyan Roy on 29 Oct 10 - No Cached

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Guest Post: Evalyn Gates on Cosmic Magnification (or - Invasion of the Giant Blue Space... - 0 views

blogs.discovermagazine.com/...f-the-giant-blue-space-amoebas astronomy astrophysics gravity-lens physics science gravity methods

shared by Todd Suomela on 19 Jul 09 - Cached

This is not just a pretty picture, however – the image packs a lot of scientific information. The authors extract the mass distribution in the cluster (which has implications for cosmological models), measure the mass-to-light ratio of the bright galaxy in the center of the cluster, and use the magnifying power of the lens to search for even more distant galaxies. The basic idea is to construct a model of the lens, starting with the cluster galaxies and a dark matter halo; then refine the model to reproduce the multiple images that are seen. Using this refined model it’s possible to predict the location of additional images of a given source, and to identify regions of high magnification that can then be examined for multiple images of other sources. Any additional images that are found can be used to further refine the model and so on.
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This galaxy has been lensed by the warp in spacetime created by the cluster. Light from the galaxy, which lies almost directly behind the center of the cluster but much farther away from us, travels along several curved paths through the cluster lens, producing multiple magnified images of the galaxy. The inset box shows a computer generated model of the unlensed source galaxy, enlarged by a factor of four so that the details, including the spiral arm structure, are visible. Without the lensing power of the cluster, we would see this galaxy as a single small blue smudge. In general, lensing will both magnify and distort (shear) images of a background source. This lens is fairly unique in that we see large but relatively intact images of the spiral galaxy, which implies that the mass distribution in the central region of the cluster must be nearly uniform.
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