## Can a New Camera Unravel the Nature of Dark Energy?

by Nancy AtkinsonThe 570 megapixel Dark Energy Camera. Credit: Fermilab

Scientists have great expectations for the newly operational Dark Energy Camera, which may significantly advance our understanding of the mysterious force expanding the Universe at an ever accelerating rate. Find out more about this highly anticipated new camera and what it is expected to reveal during live webcast from the Kavli Foundation. You’ll be able to ask questions to Fermilab scientists Brenna Flaugher, project manager for the Dark Energy Camera, and Joshua Frieman, director of the Dark Energy Survey. The webcast will be on October 12, 10-10:30 am PDT (17:30 UTC). Viewers may submit questions via Twitter using the #KavliAstro hashtag, or email to [email protected].

Watch the webcast below, or at this link.

If you miss the webcast live, afterwards you’ll be able to watch a replay on the player below, as well.

The new camera is mounted on the Blanco 4-meter telescope at the National Science Foundation’s Cerro Tolollo InterAmerican Observatory (CTIO) in Chile.

It is the widest field optical imager in astronomy today, and is capable of detecting light from over 100,000 galaxies up to 8 billion light years away. The instrument is composed of an array of 62 charged-coupled devices, and new technology will allow scientists from around the world to investigate the studies of asteroids in our solar system to the understanding of the origins and the fate of the Universe.

It is expected that in just over five years, astronomers will be able to create detailed color images of one-eighth of the sky, to discover and measure 300 million galaxies, 100,000 galaxy clusters and 4,000 supernovae.

“The Dark Energy Camera will solve the mystery of dark energy in a systematic manner,” said Andrea Kunder of CTIO in a podcast on 365 Days of Astronomy. “The idea is to observe four different probes of dark energy. You can’t see dark energy so there are four different probes of dark energy that DECam will be observing. First, DECam will observe type Ia supernova and baryon acoustic oscillations and this will be to constrain the expansion of the universe. And then galaxy clusters and weak lensing will also be observed to measure both the expansion of the universe and the growth of large scale structures. Then we can compare the results from these first two probes and the last two probes and this can reveal our understanding of gravity and intercomparisons of the results will provide cross checks and bolster confidence in the findings.”

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.

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

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.

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

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.

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

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).

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

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/

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.