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Sandra Flores

Back on The Ground - 0 views

Furnace starts trial operationThe German ESA astronaut Alexander Gerst is now back on the ground, the commissioning of an assembled by him on the ISS furnace for experiments in materials science, h...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Sandra Flores

Back on The Ground - 0 views

Furnace starts trial operationThe German ESA astronaut Alexander Gerst is now back on the ground, the commissioning of an assembled by him on the ISS furnace for experiments in materials science, h...

started by Sandra Flores on 09 Jan 15 no follow-up yet
Sandra Flores

First images of the comet - 0 views

Send Mars probes first images of the cometOn Sunday evening, the comet C / 2013 A1 (Siding Spring) is over flown at a distance of almost 140,000 kilometers on Mars. All active Mars probes have surv...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Sandra Flores

First images of the comet - 0 views

Send Mars probes first images of the cometOn Sunday evening, the comet C / 2013 A1 (Siding Spring) is over flown at a distance of almost 140,000 kilometers on Mars. All active Mars probes have surv...

started by Sandra Flores on 09 Jan 15 no follow-up yet
Sandra Flores

Comet Lovejoy visible in the night sky - 0 views

Observing Tip: Comet Lovejoy visible in the night skyLovejoy has developed over the past few weeks, far better than predicted - the chances of being able to see him in January with the naked eye, a...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Sandra Flores

Comet Lovejoy visible in the night sky - 0 views

Observing Tip: Comet Lovejoy visible in the night skyLovejoy has developed over the past few weeks, far better than predicted - the chances of being able to see him in January with the naked eye, a...

started by Sandra Flores on 09 Jan 15 no follow-up yet
Sandra Flores

Star Formation - 0 views

Heated gas stream at a cool star formation?In the inner regions of a galaxy cluster, astronomers found by Michael McDonald from the Massachusetts Institute of Technology in the USA further evidence...

stars cosmos astronomy

started by Sandra Flores on 02 Nov 14 no follow-up yet
Sandra Flores

Archaeology in the universe - 0 views

image

started by Sandra Flores on 30 Oct 14 no follow-up yet
Sandra Flores

Surface and core of the Earth in its sights - 0 views

Surface and core of the Earth in its sightsOn September 10, the Russian Plesetsk cosmodrome to be brought from the ESA GOCE satellite into orbit to determine the gravitational field and the referen...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Sandra Flores

Surface and core of the Earth in its sights - 0 views

Surface and core of the Earth in its sightsOn September 10, the Russian Plesetsk cosmodrome to be brought from the ESA GOCE satellite into orbit to determine the gravitational field and the referen...

started by Sandra Flores on 09 Jan 15 no follow-up yet
Sandra Flores

Fifth ATV's Georges Lemaître - 1 views

The fifth and final current proposed Automated Transfer Vehicle (ATV) of the European Space Agency will carry the name "Georges Lemaître". The Belgian theologian and astrophysicists is considered t...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Todd Suomela

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.
  • 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.
Sandra Flores

Revealing pattern without planets - 0 views

Revealing pattern without planets Planets around young suns are formed in a disk of gas and dust orbiting the star just created. Many such disks have now been detected around young stars. In some y...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Todd Suomela

[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.
Sandra Flores

Life will Always find a Way ??? - 0 views

Age Mild universeIf you follow the calculations of Piran and Jimenez, the universe is so mild in old age. About five billion years gamma-ray bursts were so frequent that they had never allowed the ...

started by Sandra Flores on 05 Jan 15 no follow-up yet
Sandra Flores

Life will Always find a Way ??? - 0 views

Age Mild universeIf you follow the calculations of Piran and Jimenez, the universe is so mild in old age. About five billion years gamma-ray bursts were so frequent that they had never allowed the ...

started by Sandra Flores on 09 Jan 15 no follow-up yet
Todd Suomela

[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
Andres Ruiz liked it
  • 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.
Todd Suomela

Guest Post: Tom Levenson on Isaac Newton as the First Cosmologist | Cosmic Variance - 0 views

cosmicvariance.com/...ewton-as-the-first-cosmologist

astronomy astrophysics history physics science sts

shared by Todd Suomela on 05 Jun 08 - Cached
  • To make his ambitions absolutely clear Newton used the same phrase for the title of book three. There his readers would discover “The System of the World.” This is where the literary structure of the work really comes into play, in my view. Through book three, Newton takes his audience through a carefully constructed tour of all the places within the grasp of his new physics. It begins with an analysis of the moons of Jupiter, demonstrating that inverse square relationships govern those motions. He went on, to show how the interaction between Jupiter and Saturn would pull each out of a perfect elliptical orbit; the real world, he says here, is messier than a geometer’s dream.
  • Newton knew what he had done. He was no accidental writer. A parabola, of course, is a curve that keeps on going – and that meant that at the end of a very long and very dense book, he lifted off again from the hard ground of daily reality and said, in effect, look: All this math and all these physical ideas govern everything we can see, out to and past the point where we can’t see anymore. Most important, he did so with implacable rigor, a demonstration that, he argued, should leave no room for dissent. He wrote “The theory that corresponds exactly to so nonuniform a motion through the greatest part of the heavens, and that observes the same laws as the theory of the planets and that agrees exactly with exact astronomical observations cannot fail to be true.” (Italics added).
Kalyan Roy

Why Are Quark Stars So Strange? : Discovery News - 1 views

news.discovery.com/...re-quark-stars-so-strange.html

Astronomy

shared by Kalyan Roy on 20 Jan 10 - Cached
  • First things first, neutron stars, quark stars and black holes are all born via the same mechanism: a supernova. But each of the three are progressively more massive, so they originate from supernovae produced by progressively more massive stars. So, what if a star exploded, producing something a little too massive to be called a neutron star? Well, neutron stars resist collapsing under their own gravitational pull by a characteristic of matter known as neutron degeneracy. This produces an outward force called neutron degeneracy pressure. What if the neutron star born after a supernova is too massive for this neutron degeneracy pressure to hold up against the neutron star's own gravity? In this case, it's up to the quarks that make up the neutrons to take over, preventing the body from collapsing any further. Single neutrons are composed of three quarks (two "down" quarks and one "up" quark). When quark degeneracy pressure kicks in, a quark star may be produced; the free "up" and "down" quarks get converted into "strange" quarks. Therefore, a quark star (also known as a "strange star") is made up of strange matter.
  • Using what we know from the Standard Model of particle physics, a massive quark star may have enough gravitational energy to start 'burning' strange matter. The quarks inside the core of the quark star may be abused so badly by gravitational pressure that the quarks will be converted into pure energy and neutrinos.
  • The fascinating thing with this scenario is that the quark star matter will be so dense that even the neutrinos cannot escape. However, this release of energy and generation of neutrinos creates an outward pressure countering the relentless inward gravitational pull.
  • ...2 more annotations...
  • Dai calls this extreme strange matter-burning quark star an "electroweak star"
  • Saving the best till last, the electroweak star's core would therefore be as extreme as the universe was only 10-10 seconds (that's 0.0000000001 seconds) after the Big Bang. These extreme objects would be like mini-Big Bang laboratories, maintaining a pressure where the electromagnetic and weak forces are so intertwined, they cannot be distinguished.
Janos Haits

Bolshoi Simulation | Home - 0 views

hipacc.ucsc.edu/...index.html

simulation Astronomy science space Astrophysics cosmology planetary universe galactic physics

shared by Janos Haits on 03 Oct 11 - No Cached
  • Janos Haits on 03 Oct 11
     
    The Bolshoi simulation is the most accurate cosmological simulation of the evolution of the large-scale structure of the universe yet made ("bolshoi" is the Russian word for "great" or "grand").  The first two of a series of research papers describing Bolshoi and its implications have been accepted for publication in the Astrophysical Journal. The first data release of Bolshoi outputs, including output from Bolshoi and also the BigBolshoi or MultiDark simulation of a volume 64 times bigger than Bolshoi, has just been made publicly available to the world's astronomers and astrophysicists.
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