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Zeroing in on the Mystery of Dark Matter --"We are on the Verge of Detecting a N

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  • derhexerus
    A post from The Daily Galaxy. These are amazing times we live in. Chris ____________________________________ From: vlandi@yahoo.com To: derhexer@aol.com Sent:
    Message 1 of 1 , Feb 18, 2013
      A post from The Daily Galaxy.

      These are amazing times we live in.


      From: vlandi@...
      To: derhexer@...
      Sent: 2/18/2013 6:14:46 P.M. Eastern Standard Time
      Subj: The Daily Galaxy: News from Planet Earth & Beyond

      _The Daily Galaxy: News from Planet Earth & Beyond_


      _Zeroing in on the Mystery of Dark Matter --"We are on the Verge of
      Detecting a New Particle of Nature"_
      Posted: 18 Feb 2013 08:37 AM PST

      The galaxies and other structures we see in the universe are made
      predominantly of undected dark matter. "We are so excited because we believe we are
      on the threshold of a major discovery," said Michael Turner, director of
      the Kavli Institute for Cosmological Physics at the University of Chicago,
      at a conference of the American Association for the Advancement of Science
      (AAAS). The existence of Dark matter presents a serious threat to the
      so-called Standard Model of physics mainly because it does not explain gravity.

      "On the cosmology side we now understand that this mysterious dark matter
      holds together our galaxy and the rest of the Universe," said Turner. "And
      the tantalizing thing on the cosmology side is that we have an airtight
      case that the dark matter is made of something new... there is no particle in
      the Standard Model that can account for dark matter."
      "The real question is why dark matter has six times the energy that is in
      ordinary matter," said Lisa Randall of _Harvard University_
      1.1169444444 (Harvard%20University)&t=h) . "It could be 10 trillions times
      bigger... This is an intriguing sign that there is maybe some other
      interaction we can detect."
      The ultimate dark-matter sleuth is the new _Alpha Magnetic Spectrometer_
      (http://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer) , also designated
      AMS-02, a particle physics experiment module aboard the _International Space
      Station (ISS)_ (http://en.wikipedia.org/wiki/International_Space_Station) ,
      which captures gamma rays coming from collisions of dark matter particles.
      AMS functions by sampling these high-energy particles from deep space. The
      sensitivity of the AMS is more than 100 to 1,000 times more sensitive than
      previous instruments. The first results will be published in two to three
      weeks, according to _Samuel Ting_
      (http://web.mit.edu/physics/facultyandstaff/faculty/samuel_ting.html) , a Nobel laureate and professor at the
      _Massachusetts Institute of Technology (MIT)_
      (Massachusetts%20Institute%20of%20Technology)&t=h) who is the mastermind of the two-billion-dollar
      project. Its experiments will help researchers study the formation of the
      universe and search for evidence of dark matter and antimatter.
      The device is equipped with over 300,000 data channels that require
      compression with an on-board supercomputer before the information can be
      transmitted to Earth. “The space station [AMS device] can detect particles of
      practically unlimited energy,” Ting says, which means that it can also hunt for
      proposed galaxies made of the elusive dark matter.
      Ting oversees a 500 member global team of scientist to work on this 1.5
      billion dollar project, made possible because US President Barack Obama who
      proposed to extend the space station for a minimum of 5 years beyond 2015,
      with an additional budget of 3 billion dollars per year.
      In an interview with BBC News Ting stated: “This really is the very first
      very, very precise particle physics detector. You enter into a totally new
      domain. It's very hard to predict what you'll find."
      Space-based spectrometers are not something new, but this instrument is
      particularly important because it represents the first one of its type to
      take a superconducting magnet to low-Earth orbit. The international physics
      community hopes that, through measurements collected with the AMS, they will
      be able to answer at least a small portion of yet-unanswered,
      Universe-related questions that deal with the origins and the future of the cosmos.
      Its observations will probably build up on those obtained by the Italian
      satellite PAMELA, a high-energy particle observer launched in 2006. This
      observatory has already gathered some interesting leads on pinpointing the
      first clear pieces of evidence on dark matter, and the AMS will have the
      ability to either permanently confirm or deny these findings, and the dark
      matter/dark energy theory as a whole.*
      Dark matter makes up about 23 percent of the mass-energy content of the
      universe, even though we don’t know what it is or have yet to directly see it
      (which is why it’s called “dark”).
      The image above is one of the most detailed maps of dark matter in our
      universe ever created. The location of the dark matter (tinted blue) was
      inferred through observations of magnified and distorted distant galaxies seen
      in this picture.

      "Figuring out what is dark matter has become a problem that
      astrophysicists, cosmologists and particle physicists all want to solve, because dark
      matter is central to our understanding of the universe," says _Michael S.
      Turner_ (http://en.wikipedia.org/wiki/Michael_Turner_(cosmologist)) – Rauner
      Distinguished Service Professor and Director of the Kavli Institute for
      Cosmological Physics at the University of Chicago.
      "We now have a compelling hypothesis, namely that dark matter is comprised
      of WIMPs (_Weakly Interacting Massive Particle_
      (http://en.wikipedia.org/wiki/Weakly_interacting_massive_particles) ), particles that don’t radiate
      light and interact rarely with ordinary matter. After decades of trying to
      figure out how to test the idea that dark matter is made up of WIMPs, we have
      three ways to test this hypothesis. Best of all, all three methods are
      closing in on being able to either confirm or falsify the WIMP. So the stars
      have truly aligned."
      A theoretical cosmologist trained in both particle physics and
      astrophysics, Michael Turner coined the term “dark energy” and helped establish the
      interdisciplinary field that combines cosmology and elementary particle
      "Ten years ago," Turner says, "I don't think you would've found
      astronomers, cosmologists, and particle physicists all agreeing that dark matter was
      really important. And now, they do. And all of them believe we can solve
      the problem soon. It's wonderful listening to particle physicists explain the
      evidence for dark matter, and vice versa –astronomers explaining WIMPs as
      dark matter. "
      "As cosmologists," said _Rocky Kolb_
      (http://en.wikipedia.org/wiki/Edward_Kolb) , who studies the application of elementary-particle physics to the
      _very early Universe_ (http://en.wikipedia.org/wiki/Timeline_of_the_Big_Bang)
      , and is the co-author with Michael Turner of The Early Universe, the
      standard textbook on particle physics and cosmology, "one of our jobs is to
      understand what the universe is made of. To a good approximation, the galaxies
      and other structures we see in the universe are made predominantly of dark
      matter. We have concluded this from a tremendous body of evidence, and now
      we need to discover what exactly is dark matter. The excitement now is
      that we are closing in on an answer, and only once in the history of humans
      will someone discover it. "
      "Nothing in cosmology makes sense without dark matter, says Turner. "We
      needed it to form galaxies, stars and other structures in the Universe. And
      so it's absolutely central to cosmology. We also know that none of the
      particles known to exist can be the dark matter particle. So it has to be a new
      particle of nature. Remarkably, our most conservative hypothesis right now
      is that the dark matter is a new form of matter – out there to be
      discovered and to teach us about particle physics."
      "Dark matter is absolutely central to cosmology, said Turner, "and the
      evidence for it comes from many different measurements: the amount of
      deuterium produced in the big bang, the cosmic microwave background, the formation
      of structure in the Universe, galaxy rotation curves, gravitational
      lensing, and on and on."
      "There is five times more dark matter than ordinary matter, and its
      existence allows us to understand the history of the universe beginning from a
      formless particle soup until where we are today," said Turner. "If you said,
      'You no longer have dark matter,' our current cosmological model would
      collapse. We would be back to square one."
      "Dark matter particles, or WIMPs," said Turner, "don’t interact with
      ordinary matter often. It's taken 25 years to improve the sensitivity of our
      detectors by a factor of a million, and now they have a good shot at detecting
      the dark matter particles. Because of the technological developments, we
      think we are on the cusp of a direct detection. Likewise for indirect
      detection. We now have instruments like the Fermi satellite (the Fermi Gamma-ray
      Space Telescope) and the IceCube detector (the IceCube Neutrino Observatory
      at the South Pole) that can detect the ordinary particles (positrons,
      gamma rays or neutrinos) that are produced when dark matter particles
      annihilate, indirectly allowing dark matter to be detected. IceCube is big enough to
      detect neutrinos that are produced by dark matter annihilations in the
      Answering the observation that the dark matter particle might not be
      detectable, Turner said that for 20 to 30 years, this idea that dark matter is
      part of a unified theory has been our Holy Grail and has led to the WIMP
      hypothesis and the belief that the dark matter particle is detectable. "But
      there’s a new generation of physicists that is saying, 'Well, there's an
      alternative view. Dark matter is actually just the tip of an iceberg of another
      world that is unrelated to our world. And I cannot even tell you about
      that world. There are no rules for that other world, at least that we know of
      Sadly, this point of view could be correct and might mean the solution to
      the dark matter problem is still very far away, that discovering what dark
      matter actually is could be 100 years away.
      The Daily Galaxy via _http://www.kavlifoundation.org_
      (http://www.kavlifoundation.org/) and AFP 2013
      Image Credit: NASA/JPL-Caltech/ESA/Institute of Astrophysics of Andalusia,
      University of Basque Country/JHU

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      _Image of the Day: The Largest Galaxy in the Observable Universe?_
      Posted: 18 Feb 2013 08:59 AM PST

      The spectacular _barred spiral galaxy_
      (http://en.wikipedia.org/wiki/Barred_spiral_galaxy) NGC 6872 has ranked among the biggest stellar systems for
      decades. A eam of astronomers from the United States, Chile and Brazil have
      crowned it the largest-known spiral, based on archival data from NASA's
      _Galaxy Evolution Explorer_ (http://www.galex.caltech.edu/) (GALEX) mission,
      which has since been loaned to the _California Institute of Technology_
      -118.125494 (California%20Institute%20of%20Technology)&t=h) . Measuring
      tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than
      522,000 light-years, making it more than five times the size of our Milky Way.

      "Without GALEX's ability to detect the ultraviolet light of the youngest,
      hottest stars, we would never have recognized the full extent of this
      intriguing system," said lead scientist Rafael Eufrasio, a research assistant at
      NASA's _Goddard Space Flight Center_
      d%20Space%20Flight%20Center)&t=h) in Greenbelt, Md., and a doctoral
      student at _Catholic University of America_
      University%20of%20America)&t=h) in Washington.

      The galaxy's unusual size and appearance stem from its interaction with a
      much smaller disk galaxy named IC 4970, which has only about one-fifth the
      mass of NGC 6872. The odd couple is located 212 million light-years from
      Earth in the southern constellation Pavo. Astronomers think large galaxies,
      including our own, grew through mergers and acquisitions -- assembling over
      billions of years by absorbing numerous smaller systems. Intriguingly, the
      gravitational interaction of _NGC 6872 and IC 4970_
      (http://en.wikipedia.org/wiki/NGC_6872_and_IC_4970) may have done the opposite, spawning what may
      develop into a new small galaxy.
      "The northeastern arm of NGC 6872 is the most disturbed and is rippling
      with star formation, but at its far end, visible only in the ultraviolet, is
      an object that appears to be a tidal dwarf galaxy similar to those seen in
      other interacting systems," said team member Duilia de Mello, a professor
      of astronomy at Catholic University.
      Computer simulations of the collision between NGC 6872 and IC 4970
      reproduce the basic features of the galaxies as we see them today. They indicate
      that IC 4970's closest encounter occurred 130 million years ago and that the
      smaller galaxy followed a path (dashed curve) close to the plane of the
      spiral's disk and in the same direction it rotates. The tidal dwarf candidate
      is brighter in the ultraviolet than other regions of the galaxy, a sign it
      bears a rich supply of hot young stars less than 200 million years old.
      The researchers studied the galaxy across the spectrum using archival data
      from the European Southern Observatory's Very Large Telescope, the Two
      Micron All Sky Survey, and NASA's _Spitzer Space Telescope_
      (http://www.spitzer.caltech.edu/) , as well as GALEX. By analyzing the distribution of energy
      by wavelength, the team uncovered a distinct pattern of stellar age along
      the galaxy's two prominent spiral arms. The youngest stars appear in the far
      end of the northwestern arm, within the tidal dwarf candidate, and stellar
      ages skew progressively older toward the galaxy's center. The southwestern
      arm displays the same pattern, which is likely connected to waves of star
      formation triggered by the galactic encounter.
      A 2007 study by Cathy Horellou at _Onsala Space Observatory_
      1.9177777778 (Onsala%20Space%20Observatory)&t=h) in Sweden and Baerbel
      Koribalski of the Australia National Telescope Facility developed computer
      simulations of the collision that reproduced the overall appearance of the
      system as we see it today. According to the closest match, IC 4970 made its
      closest approach about 130 million years ago and followed a path that took
      it nearly along the plane of the spiral's disk in the same direction it
      rotates. The current study is consistent with this picture.
      As in all barred spirals, NGC 6872 contains a stellar bar component that
      transitions between the spiral arms and the galaxy's central regions.
      Measuring about 26,000 light-years in radius, or about twice the average length
      found in nearby barred spirals, it is a bar that befits a giant galaxy. The
      team found no sign of recent star formation along the bar, which indicates
      it formed at least a few billion years ago. Its aged stars provide a fossil
      record of the galaxy's stellar population before the encounter with IC
      4970 stirred things up.
      "Understanding the structure and dynamics of nearby interacting systems
      like this one brings us a step closer to placing these events into their
      proper cosmological context, paving the way to decoding what we find in
      younger, more distant systems," said team member and Goddard astrophysicist Eli
      The Daily Galaxy via
      _http://www.nasa.gov/mission_pages/galex/galex20130110.html_ (http://www.nasa.gov/mission_pages/galex/galex20130110.html)
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