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"Gravitinos" --Will They Unlock the Mystery of Dark Matter in the Universe?

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  • derhexerus
    Interesting post from The Daily Galaxy Chris (Madness takes its toll. Please have exact change) ____________________________________ From: vlandi@yahoo.com
    Message 1 of 1 , Jan 23, 2013
      Interesting post from The Daily Galaxy


      (Madness takes its toll. Please have exact change)

      From: vlandi@...
      To: derhexer@...
      Sent: 1/23/2013 6:12:23 P.M. Eastern Standard Time
      Subj: The Daily Galaxy: News from Planet Earth & Beyond

      _The Daily Galaxy: News from Planet Earth & Beyond_


      _"Gravitinos" --Will They Unlock the Mystery of Dark Matter in the
      Posted: 23 Jan 2013 08:38 AM PST

      Astrophysicists have known for the last 80 years that most of the universe
      consists of an unknown, _dark matter_
      (http://en.wikipedia.org/wiki/Dark_matter) . The solution to the mystery may now be just around the corner. "We
      are looking for a new member of our particle zoo in order to explain dark
      matter. We know that it is a very exotic beast. And we have found a
      plausible explanation," reports Are Raklev, an associate professor in particle
      physics in the _University of Oslo_
      (University%20of%20Oslo)&t=h) 's Department of Physics --the university's leading theorist
      in astroparticle physics. Raklev has launched a model that explains what
      dark matter may consist of and how one can discover the invisible particles
      experimentally.Even though dark matter is invisible, astrophysicists know
      it exists. Without this dark matter it is impossible to explain how the
      visible things in the universe hang together. An 80 year fight The world
      famous, Swiss physicist _Fritz Zwicky_ (http://en.wikipedia.org/wiki/Fritz_Zwicky)
      was speculating on what dark matter might be as early as the 1930s.
      Astrophysicists have calculated that 80 per cent of all the mass in the universe
      is dark, invisible matter. Thanks to gravity this dark matter clumps
      together as ordinary matter. Dark matter can explain why stars move like they
      do. Dark matter may also explain the rotation speed of galaxies.
      "Even though we can calculate how much dark matter there is in the
      universe, we still know little about what dark matter is. The particles in dark
      matter must either have a lot of mass, or there must be very many of them.
      _Neutrinos_ (http://en.wikipedia.org/wiki/Neutrino) meet all the requirements
      of dark matter. But there is one big difficulty. They have far too little
      mass." Raklev is now trying to prove that dark matter consists of
      gravitinos. This is a particle that has been unfairly treated for years. Gravitinos
      are the _supersymmetric partner_
      (http://en.wikipedia.org/wiki/Superpartner) of gravitons.
      Or, to be even more precise: "The gravitino is the hypothetical,
      supersymmetric partner of the hypothetical particle graviton, so it is also
      impossible to predict a more hypothetical particle than this," laughs Raklev
      (below), who writes on his web pages that he is looking for dark material both
      under his sofa and other places.
      In order to dig deeper into why Raklev believes dark matter consists of
      gravitinos, and have any chance at all of understanding the theory behind
      gravitinos, Apollon has to take a couple of steps back: Step 1: Supersymmetry
      Physicists want to find out whether or not nature is supersymmetric.
      Supersymmetry means that there is a symmetry between matter and forces. For each
      type of electron and quark there is a corresponding heavy, supersymmetric
      partner. The supersymmetric particles were created in the instant after the
      _Big Bang_ (http://en.wikipedia.org/wiki/Big_Bang) . If some of them have
      survived to today, they may be what dark matter is made of.
      The supersymmetric partner of the gravitino is, as Apollon said, the
      graviton. "A graviton is the particle we believe mediates gravitational force,
      just like a photon, the light particle, mediates electromagnetic force.
      While gravitons do not weigh anything at all, gravitinos may weigh a great
      deal. If nature is supersymmetric and gravitons exist, then gravitinos also
      exist. And vice versa. This is pure mathematics." But there is a small but.
      Physicists cannot demonstrate the relationship between gravitons and
      gravitinos before they have managed to unify all the forces of nature.
      Step 2: The forces of nature One of the biggest things physicists long to
      do is to unify all the forces of nature in a single theory. In the middle
      of the last century physicists discovered that electricity and magnetism
      were part of the same force of nature. This force has since been called
      electromagnetism. Two of the other forces of nature are the strong nuclear force
      and the weak nuclear force. The weak nuclear force can be seen in, among
      things, radioactivity. The strong nuclear force is ten billion times as
      strong and binds together neutrons and protons.
      In the 1970s, electromagnetism was unified with the strong and _weak
      nuclear forces_ (http://en.wikipedia.org/wiki/Weak_interaction) in what
      physicists call the standard model. The fourth force of nature is gravity. Even
      though it is unbelievably painful to fall down stairs, gravity is the weakest
      of the _four forces of nature_
      (http://en.wikipedia.org/wiki/Fundamental_interaction) . The problem is that physicists have not yet been able to unify
      gravity with the three other forces of nature.
      The day physicists gain a unified understanding of all four forces of
      nature, they will gain a unique understanding of the world. This will make it
      possible to describe all imaginable interactions between all possible
      particles in nature. Physicists call this the ToE Theory (_Theory of Everything_
      (http://en.wikipedia.org/wiki/Theory_of_everything) ). In order to unify
      gravitational force with the other three forces of nature we have to understand
      gravity as quantum theory. This means we need a theory in which the
      particle graviton is included in the atomic nucleus.
      Researchers are now looking for signs of both supersymmetry and the ToE
      Theory. Discovering the graviton would be an enormous step in this direction.
      Reveals dark matter As the reader may have understood, it is very
      difficult to research dark matter. This is because dark matter has no
      electromagnetic relationships to terrestrial particles at all.
      One example of dark matter is the aforementioned neutrino. Unfortunately,
      neutrinos make up only an imperceptibly tiny part of dark matter. Even
      though it has not been possible to observe dark matter, several billion
      neutrinos race through your body every second. However, their speed is somewhat
      limited. The particles move just as slowly as the speed the solar system
      moves around the galaxy.
      In other words, a mere 400 kilometres a second. "When there are no
      electromagnetic relationships with visible particles, the particles can pass right
      through us without any measuring instruments detecting them. This is where
      supersymmetry comes in. If supersymmetry is right, physicists can explain
      why there is dark matter in the universe. That is what is fun about my
      job," laughs Raklev. He is now asserting that dark matter mostly consists of
      "Supersymmetry simplifies everything. If the ToE Theory exists, in other
      words if it is possible to unify the four forces of nature, gravitinos must
      exist." The gravitinos were formed right after the Big Bang. "A short time
      after the Big Bang we had a soup of particles that collided. Gluons, which
      are the force bearing particles in the strong nuclear force, collided with
      other gluons and emitted gravitinos. Many gravitinos were formed after the
      Big Bang, while the universe was still plasma. So we have an explanation of
      why gravitinos exist."
      Physicists have up to now viewed gravitinos as a problem. They have
      believed that the theory of supersymmetry does not work because there are too
      many gravitinos. "Physicists have therefore strived to eliminate gravitinos
      from their models. We, on the other hand, have found a new explanation that
      unifies the supersymmetry model with dark matter that consists of
      gravitinos. If dark matter is not stable, but just very long lived, it is possible to
      explain how dark matter consists of gravitinos."
      In the old models dark matter was always everlasting. This meant that
      gravitinos were a bothersome part of the supersymmetry model. In Raklev's new
      model, their life span is no longer endless. Nonetheless, the average life
      span of gravitinos is very long and actually longer than the life span of
      the universe. However, there is a big difference between an unending life
      span and a life span of more than 15 billion years. With limited a life span,
      gravitinos must be converted into other particles. It is precisely this
      conversion effect that can be measured. And the conversion explains the model.

      "We believe that almost all dark matter is gravitinos. The explanation
      lies in very hard mathematics. We are developing special models that calculate
      the consequences of these theories and we predict how the particles can be
      observed in experiments." The measurements are underway Researchers are
      now trying to test this experimentally and explain why these new particles
      have not yet been seen in the CERN experiments in Geneva in Switzerland.
      "On the other hand, it should theoretically possible to observe them from
      a space probe." The simplest way of observing gravitinos could be studying
      what happens if two particles collide out in the universe and are converted
      into other particles such as photons or antimatter. Even though the
      collisions occur very rarely, there is still so much dark matter in the universe
      that a significant number of photons should be able to be produced.
      The big problem is that gravitinos do not collide. "At least it happens so
      rarely that we could never hope to observe it." Nonetheless there is hope.
      "Luckily for us, gravitinos are not one hundred per cent stable. They are
      converted into something else at some point. We can predict what the signal
      looks like after gravitinos have been converted. The conversion will send
      out a small electromagnetic wave. This is also called a gamma ray."
      NASA's Fermi-LAT space probe is currently measuring gamma rays. A number
      of research groups are now analysing the data. "So far we have only seen
      noise. But one of the research groups claim they have observed a small,
      suspicious surplus of gamma rays from the centre of our galaxy. Their
      observations may fit our models," says Raklev.
      The Daily Galaxy via University of Oslo Related articles

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      _From the X Files: "A Meteroite That Crashed to Earth this December
      Contains Proof that We are All Aliens"_
      Posted: 23 Jan 2013 07:53 AM PST

      Sri Lankan-born British mathematician, _Chandra Wickramasinghe_
      (http://en.wikipedia.org/wiki/Chandra_Wickramasinghe) , discovered that a two-inch
      wide meteorite that crash landed in a fireball in central Sri Lanka in
      December was pitted with tiny fossils of algae, similar to the kind found in
      seaweed. Wickramasinghe, currently Director of the 'Cardiff Centre for
      Astrobiology', was a student and collaborator of _Fred Hoyle_
      (http://en.wikipedia.org/wiki/Fred_Hoyle) . Their joint work on the infrared spectra of
      interstellar grains led to developing the hypothesis of panspermia that proposes that
      cosmic dust in the _interstellar medium_
      (http://en.wikipedia.org/wiki/Interstellar_medium) and in comets is partly organic, and that _life on Earth_
      (http://en.wikipedia.org/wiki/Organism) was 'seeded' from
      space.Wickramasinghe believes the discovery proves we are not alone in the universe: “
      These finds are crushing evidence that human life started outside Earth.”
      The rock was one of several fragments of a meteorite which crash landed in
      a spectacular fireball and were still smoking when villagers living near
      the city of _Polonnaruwa_ (http://whc.unesco.org/en/list/201) picked them
      up. The fossils, discovered when the rocks were examined under a powerful
      scanning electron microscope in a British laboratory, are similar to
      micro-organisms found in fossils from the dinosaur age 55 million years ago.
      Skeptics say the rock had probably become contaminated with algae fossils from
      But Wickramasinghe replies that “The algae organisms are similar to ones
      found in Earth fossils, but the rock also has other organisms we have not
      “We are all aliens – we share a _cosmic ancestry_
      (http://en.wikipedia.org/wiki/Cosmic_ancestry) , Wickramasinghe says. "Each time a new planetary
      system forms, a few surviving microbes find their way into comets. These then
      multiply and seed other planets. These latest finds are just more evidence
      to point to the overwhelming fact that life on Earth began on other worlds.

      The Daily Galaxy via www.dailymail.co.uk/
      Image credit top of page: S Molau and P Jenniskens NASA Ames Research
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      Microbes on Earth"_


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