Can a New Camera Unravel the Nature of Dark Energy?

10 Replies to “Can a New Camera Unravel the Nature of Dark Energy?”

1. So really, it’s a wide field camera. The claim that it “will solve the mystery of dark energy” is pure chutzpah. We already have type 1a SN and ABO data – and we already have strong and weak lensing data. Now we are going to get these data through a shiny new wide field camera. Yep, it will provide cross-checks – that’s the story.

   1. I think this will provide a data base of many receding galaxies and give empirical support for the constancy of dark energy through the universe. Of course we already have some indication of this from the CMB.

      LC

      1. My point being that I expect we will continue finding more evidence for the universe’s accelerating expansion and we will continue to find no evidence for dark energy – which is not so much mysterious as undetectable and seemingly unfalsifiable.

      2. The Friedman-Lemaitre-Robertson-Walker spacetime results in a Hamiltonian constraint equation for the scale parameter a of the universe

         (a’/a)^2 = (8?G/3)?, a’ = da/dt

         for the k = 0 flat space model. The Hubble parameter (or constant in space) is H = (a’/a)^2. The density of mass-energy in the universe ? determines this dynamics. If ? is a constant this equation is a simple differential equation

         a’ = sqrt{(8?G/3)?}a

         which has the solution

         a = exp[t sqrt{(8?G/3)?}]

         which is the exponential expansion we observe. The generator of this expansion (using generator in a sense of Noether’s theorem) is this energy density ?. This is a constant energy that fills the universe. This is the “dark energy.”

         This dark energy is likely the quantum vacuum. This is likely due to the non-zero energy of the zero particle state, or the zero point energy. There are of course questions, for quantum field theory has troubles predicting this. In fact there is the infamous 123 orders of magnitude problem.

         LC

      3. I think you are just stating that as the universe expands its mass-energy density remains constant. An equally valid view is that as the universe expands, its geometry stays flat.
         This is no more or less puzzling than energy appearing out of nowhere but it does avoid the initial premise of ‘a miracle happens here’ in order to solve the equation.

      4. General relativity is odd with respect to energy conservation. Energy conservation in spacetimes only exists if there is an isometry, defined by something called a Killing vector, that acts upon the energy component of a momentum vector so as to project onto it as a constant. This is a form of Noether’s theorem; a conservation law is a manifestation of a symmetry. A spacetime must have a time-like symmetry to define energy conservation. Spacetimes that define cosmology are in the Petrov-Penrose-Pirani classification scheme such that there is no isometry or symmetry associated with energy conservation.

         This is one of those quietly spoken aspects about the foundations of physics. Teachers and professors spend years teaching how energy is conserved. It then turns out that things are a bit more complicated!

         LC

      5. Not really getting your point. To maintain energy density in an expanding universe you need a constant input of new energy (out of nowhere), Assigning this role to vacuum energy is not a satisfactory solution (given the infamous 123 orders of magnitude problem).

      6. The space is a flat R^3 space, or Euclidean space that is infinite in extent. If there is a vacuum energy density it means the total vacuum energy is infinite. So while points are exponentially expanding apart, and any volume region grows and contain more energy, the creation of energy by this expansion is somewhat paradoxical, if not pathological in a way.

         The 123 order of magnitude problem most likely means that we do not know how vacuum processes cancel. In pure supersymmetry boson and Fermi-Dirac field has positive and negative vacua. The superpairs in effect cancel out their respective vacuum energy contributions. The difficulties come with the fact that supersymmetry is broken at low energy. We could say this is a work in progress.

         LC

2. DECam is particularly sensitive to red and redshift light, at present it is conducting a battery of initiation tests and commences it’s official survey role next December. The Pan-Starss instrument in Hawai’i remains the largest astronomical camera. There are some additional photographs and technical details of the new camera on the Dark Energy Survey website, just click on the right hand column “A 570-Megapixel Camera Meant To Unravel Dark Energy’s Mystery” on the main page when you enter:

   http://www.darkenergysurvey.org/

3. Congratulation to all
   scientists those who are discovered this camera for detecting bark particle.

   I calculate the accurate mass of Photon, Graviton and Black
   particle.

   The mass of a photon is 1.659619614×10-54 gram, mass of graviton is 1.948428603×10-72 gram. 10^6 black particle is able to form a
   graviton and 10^24 black particle can form a photon particle. We can give an
   example here; some times we find diamond in coal mine. Coal is nothing but a
   carbon, diamond also carbon. Only difference in structure. That means number of
   particles differ means properties differ. Thus matter differs. From this idea we can
   assume that Black particles forms graviton photon. Thus matter
   is made by the photons. Because,
   according to Einstein equation, E = m c^2, all matter can covert in energy,
   again, energy is bunch of photon or quanta. This proves that, all matter is
   made by the photos.

   The mass of
   photon, graviton written in my book Complete Unified Theory (page-424, 1998).

   So, I want
   to request to you and your tem to measure the mass of photon, graviton and then
   you will get the mass of dark particle.

   Nirmalendu
   Das

   Email : [email protected]

   Dated:
   13-10-2012.

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