3D Mapping Dark Energy to Understand the Universe

According to the traditional ideas of the Big Bang, there was a moment when nothing existed except for a tiny point, called a singularity. Something caused that singularity to become unstable and explode in such a way that everything was created. It’s an idea that can give a brain cramp to even the most brilliant of thinkers and the mechanics of this moment of creation, before which there was no space or time, has occupied the intellectual lives of several generations of philosophers, physicists, and laypeople since its development. As with any explosion, matter continues to move away from its source and it was originally theorized that eventually that matter would begin to slow its movement away from the center. However, data collected from the 1990s forward has indicated that rather than slowing down, the universe’s expansion is actually speeding up.

If you pay any attention to advanced physics at all, you will already know that simply because an idea defies Newtonian logic, that is no reason to discount it. The strange nature of the laws of nature at the scale of the incredibly small or the enormously large have really only proved one thing: if you think you understand quantum physics, you don’t understand quantum physics. Given the incomprehensible nature of the subject matter combined with tantalizing glimpses of the fantastic nature of the answers it can provide, it comes as no surprise that the latest theory to come out of physics regarding the accelerating expansion of the universe involves a magical sounding substance known as dark energy. This is not the same thing as that nasty feeling you get when your mother gives you the evil eye. Dark energy is a diffuse energy that is evenly distributed throughout the whole of space, but that has been very difficult for scientists to detect because it gives off no light. There is another aspect to its name, as physicist and author Brian Greene revealed:

“Dark also describes well the many gaps in our understanding. No one can explain the dark energy’s origin, fundamental composition, or detailed properties – issues currently under intense investigation…But, even with the open questions, detailed observations using the Hubble Space Telescope and other earth-based observatories have reached consensus on the amount of dark energy [and] have concluded that the dark energy filling space contributes approximately 73 percent of the critical density.”

Now, with formal approval of a 3D sky-mapping project, called the Dark Energy Spectroscopic Instrument (DESI), preparations are beginning to gather data from the light from millions of galaxies. One of the types of data that will be collected are precise measurements of objects’ redshift, so called because objects moving away from us give us light that has shifted to the redder end of the spectrum. This redshift data will help scientists understand how fast these objects are moving which tells them more about the acceleration of the universes’ expansion and therefore provides more information to help create a picture of this pervasive dark energy.

The mapping surveys performed by powerful telescopes will be supplemented by the information provided by DESI which will give a picture of how the universe has been changing over time. Dustin Lang, a DESI imaging scientist with the University of Toronto, explained:

“I like to think of the imaging surveys as building the 2D maps, while DESI adds the third dimension. The crucial third dimension allows us to measure how galaxies cluster together in space over the history of the universe.”

His point is reinforced by Risa Wechsler of the SLAC National Accelerator Laboratory at Stanford University and the co-spokesperson for DESI:

“DESI will be able to make a 3D map of the universe using an order of magnitude more redshifts than currently exist. This will allow us to probe the physics of the universe and discover the true nature of dark energy.”

With the stage of funding just triggered in this multi-phase project, the major components of this massive data gathering project will begin to be fabricated. One of those components is a pie-shaped section, called a petal, that will hold the cylindrical robots that will each point a fiber optic cable in a specific direction in order to collect light from a particular set of galaxies, stars, or quasars. This light collection will give scientists the ability to peer back in time, approximately 11 billion years worth of it. That doesn’t quite bring us to the moment of the big bang, estimated to have taken place 13.7 billion years ago, but its definitely far enough to begin to provide us information about the creation of everything, ever, everywhere. Discuss further in the 3D Sky Mapping forum over at 3DPB.com.

[Source/Images: Berkeley Lab]