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Kalyan Roy

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

  • 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.
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  • 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.
Maluvia Haseltine

Study plunges standard Theory of Cosmology into Crisis - 0 views

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    As modern cosmologists rely more and more on the ominous "dark matter" to explain otherwise inexplicable observations, much effort has gone into the detection of this mysterious substance in the last two decades, yet no direct proof could be found that it actually exists. Even if it does exist, dark matter would be unable to reconcile all the current discrepancies between actual measurements and predictions based on theoretical models. Hence the number of physicists questioning the existence of dark matter has been increasing for some time now.
Todd Suomela

[0903.4849] Dark Matter Candidates - 0 views

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    An overview is given of various dark matter candidates. Among the many suggestions given in the literature, axions, inert Higgs doublet, sterile neutrinos, supersymmetric particles and Kaluza-Klein particles are discussed.
Maluvia Haseltine

Integral satellite disproves dark matter origin for mystery radiation - 0 views

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    More holes in the dark matter hypotheses
Astro Biology

Know When Milky Way Collision Occur - 0 views

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    NASA scientist have found proof that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago. Are you also interested to know how galaxies form, evolve and interact?
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    NASA scientist have found proof that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago. Are you also interested to know how galaxies form, evolve and interact?
Ivan Horvat

Yet another "buying your first scope" guide - 0 views

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    Despite all warnings, and sane advice not to buy a telescope, but rather start with a good pair of binoculars, you decided that you want one, no matter what. It's all right; I did the same thing. I think most amateur astronomers did that too
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

Video Marketing Toiday - 0 views

Well - it Doesn't Matter who you are  - but you need not Skip a good video to preset yourself or your Business. you should be aware of the power of video Marketing in the internet Arena. So if...

started by Sandra Flores on 22 Jan 15 no follow-up yet
Todd Suomela

Astronomers Crowdsource the Definition of a Galaxy - Technology Review - 2 views

  • So what to do? Today, Duncan Forbes at Swinburne University in Australia and Pavel Kroup at the University of Bonn in Germany put forward a novel solution. They outline the various characteristics that astronomers think about when classifying galaxies. These include factors such as the presence of stars, so gas clouds can't be defined as galaxies; being gravitationally bound, so materials that has been stripped away by another galaxy wouldn't count; whether the system is stable or not; whether it hosts a good variety of different types of star, which excludes globular clusters which contain only similar stars; and whether it is held together by dark matter, which many galaxies seem to be. There are other factors too, of course. (Although they do not include the presence of a black hole at the centre of a galaxy as a defining characteristic , which is odd given the growing interest in the link between galactic evolutoin and black holes.) Forbes and Kroup go on to suggest that the best way to achieve consensus is to crowdsource the problem. In other works, they want to use the wisdom of the crowd to determine what factors are important what aren't.
Todd Suomela

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

  • 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.
Kalyan Roy

The Dark Attractor: What's Pulling the Milky Way Towards It at 14-Million MPH? - 1 views

  • A huge volume of space that includes the Milky Way and super-clusters of galaxies is flowing towards a mysterious, gigantic unseen mass named mass astronomers have dubbed "The Great Attractor," some 250 million light years from our Solar System.
  • The Great Attractor is a diffuse concentration of matter some 400 million light-years in size located around 250 million light-years away within the so-called "Centaurus Wall" of galaxies , about seven degrees off the plane of the Milky Way. X-ray observations with the ROSAT satellite then revealed that Abell 3627 is at the center of the Great Attractor. It lies in the so-called Zone of Avoidance, where the dust and stars of the Milky Way's disk obscures as much as a quarter of the Earth's visible sky.
Sergio Perez

SFT_preprint-EN_2_col.pdf - 0 views

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    Unification theory with no extra dimensions. The first part unifies the strong nuclear force with the gravitational force in a mathematical way; the quantum vacuum is treated as a deformable system by the strong nuclear force. The second part unifies the nuclear force with the quantum vacuum in a hypothetical structure; the quantum vacuum is treated as a supersymmetric and metastable system with properties related to the different types of particles' motion.
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