Physics

Dark Matters Before The Big Bang

Mysteries sing to us a mesmerizing song that tantalizes us with the unknown, and the nature of the Universe itself is the most profound of all haunting mysteries. Where did it come from, and did it have a beginning, and if it really did have a beginning, will it end–and, if so, how? Or, instead, is there an eternal Something that we may never be able to understand because the answer to our very existence resides far beyond the horizon of our visibility–and also exceeds our human abilities to comprehend? It is currently thought that the visible Universe emerged about 14 billion years ago in what is commonly called the Big Bang, and that everything we are, and everything that we can ever know emerged at that remote time. Adding to the mystery, eighty percent of the mass of the Cosmos is not the atomic matter that we are familiar with, but is instead made up of some as yet undiscovered non-atomic particles that do not interact with light, and are thus invisible. In August 2019, a cosmologist from Johns Hopkins University in Baltimore, Maryland, proposed that this transparent non-atomic material, that we call the dark matter, may have already existed before the Big Bang.

The study, published in the August 7, 2019 issue of Physical Review Letters, presents a new theory of how the dark matter was born, as well as how it might be identified with astronomical observations.

“The study revealed a new connection between particle physics and astronomy. If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang, too,” explained Dr. Tommi Tenkanen in an August 8, 2019 Johns Hopkins University Press Release. Dr. Tenkanen is a postdoctoral fellow in Physics and Astronomy at the Johns Hopkins University and the study’s author.

For years, scientific cosmologists thought that dark matter must be a relic substance from the Big Bang. Researchers have long tried to solve the mystery of dark matter, but so far all experimental hunts have turned up empty-handed.

“If dark matter were truly a remnant of the Big Bang, then in many cases researchers should have seen a direct signal of dark matter in different particle physics experiments already,” Dr. Tenkanen added.

Matter Gone Missing

The Universe is thought to have been born about 13.8 billion years ago in the form of an exquisitely small searing-hot broth composed of densely packed particles–generally simply referred to as “the fireball.” Spacetime has been growing colder and colder ever since, as it expands–and accelerates as it expands–from its original furiously hot and glaringly brilliant initial state. But what composes our Cosmos, and has its mysterious composition changed over time? Most of our Universe is “missing”, meaning that it is made up of an unidentified substance that is called dark energy. The identity of the dark energy is probably more mysterious than that of the dark matter. Dark energy is causing the Universe to speed up in its relentless expansion, and it is often thought to be a property of Space itself.

On the largest scales, the entire Cosmos appears to be the same wherever we look. Spacetime itself displays a bubbly, foamy appearance, with enormous heavy filaments braiding around one another in a tangled web appropriately referred to as the Cosmic Web. This enormous, invisible structure glares with glowing hot gas, and it sparkles with the starlight of myriad galaxies that are strung out along the transparent filaments of the Web, outlining with their brilliant stellar fires that which we would otherwise not be able to see. The flames of a “million billion trillion stars” blaze like dewdrops on fire, as they cling to a web woven by a gigantic, hidden spider. Mother Nature has hidden her many secrets very well.

Vast, almost empty, and very black cavernous Voids interrupt this mysterious pattern that has been woven by the twisted filaments of the invisible Web. The immense Voids host very few galactic inhabitants, and this is the reason why they appear to be empty–or almost empty. The massive starlit dark matter filaments of the Cosmic Web braid themselves around these black regions, weaving what appears to us as a twisted knot.

We cannot observe most of the Universe. The galaxies, galactic clusters, and galactic superclusters are gravitationally trapped within invisible halos composed of the transparent dark matter. This mysterious and invisible pattern, woven into a web-like structure, exists throughout Spacetime. Cosmologists are almost certain that the ghostly dark matter really exists in nature because of its gravitational influence on objects that can be directly observed–such as the way galaxies rotate. Although we cannot see the dark matter because it doesn’t dance with light, it does interact with visible matter by way of the force of gravity.

Recent measurements indicate that the Cosmos is about 70% dark energy and 25% dark matter. A very small percentage of the Universe is composed of so-called “ordinary” atomic matter–the material that we are most familiar with, and of which we are made. The extraordinary “ordinary” atomic matter accounts for a mere 5% of the Universe, but this runt of the cosmic litter nonetheless has formed stars, planets, moons, birds, trees, flowers, cats and people. The stars cooked up all of the atomic elements heavier than helium in their searing-hot hearts, fusing ever heavier and heavier atomic elements out of lighter ones (stellar nucleosynthesis). The oxygen you breathe, the carbon that is the basis of life on Earth, the calcium in your bones, the iron in your blood, are all the result of the process of nuclear-fusion that occurred deep within the cores of the Universe’s vast multitude of stars. When the stars “died”, after having used up their necessary supply of nuclear-fusing fuel, they sent these newly-forged atomic elements singing out into the space between stars. Atomic matter is the precious stuff that enabled life to emerge and evolve in the Universe.

The Universe may be weirder than we are capable of imagining it to be. Modern scientific cosmology began when Albert Einstein, during the first decades of the 20th-century, devised his two theories of Relativity–Special (1905) and General (1915)–to explain the universal mystery. At the time, astronomers thought that our barred-spiral, starlit Milky Way Galaxy was the entire Universe–and that the Universe was both unchanging and eternal. We now know that our Galaxy is merely one of billions of others in the visible Universe, and that the Universe does indeed change as Time passes. The Arrow of Time travels in the direction of the expansion of the Cosmos.

At the moment our Universe was born, in the tiniest fraction of a second, it expanded exponentially to reach macroscopic size. Although no signal in the Universe can travel faster than light in a vacuum, space itself can. The incredibly and unimaginably tiny Patch, that inflated to become our Cosmic home, started off smaller than a proton. Spacetime has been expanding and cooling off ever ince. All of the galaxies are traveling farther and farther apart as Space expands, in a Universe that has no center. Everything is zipping speedily away from everything else, as Spacetime relentlessly accelerates in its expansion, perhaps ultimately doomed to become an enormous, frigid expanse of empty blackness in the very remote future. Scientists frequently compare our Universe to a loaf of leavening raisin bread. The dough expands and, as it does so, it carries the raisins along with it– the raisins become progressively more widely separated because of the expansion of the leavening bread.

The visible Universe is that relatively small expanse of the entire unimaginably immense Universe that we are able to observe. The rest of it–most of it–is far beyond what we call the cosmological horizon. The light traveling to us from those incredibly distant domains originates beyond the horizon of our visibility, and it has not had sufficient time to reach us since the Big Bang because of the expansion of the Universe.

The temperature of the original primordial fireball was almost, but not quite, uniform. This extremely small deviation from perfect uniformity caused the formation of everything we are and know. Before the faster-than-light period of inflation occurred, the exquistely tiny primeval Patch was completely homogeneous, smooth, and was the same in every direction. Inflation explains how that completely homogeneous, smooth Patch began to ripple.

The tiny fluctuations, or primordial ripples, at the birth of Spacetime, occurred in the smallest units that can be used to measure (quantum). The theory of inflation explains how these tiny ripples in the baby Universe would ultimately grow into large-scale structures like galaxies, galactic clusters, and galactic superclusters.

The bizarre quantum world defies common sense. It is a jittery, foamy stage where absolutely nothing at all can remain perfectly still, and where Time has no meaning. The originally smooth and isotropic Universe formed tiny hills and valleys. The valleys became emptier and emptier, while the hills grew higher and higher; heavier and heavier. This was because of the force of gravity. Gravity pulled the original material of the primeval Universe into the heavier, higher hills. These “hills”eventually gravitationally hoisted in more and more of the matter composing the primordial broth. The less well-endowed plains, that were not gifted with the same powerful gravitational pull as the heavy hills, became ever more and more barren of this primordial broth. The distribution of mass in the primordial Universe was completely random–the outcome of strong gravitational influences resulting from jittering fluctuations on the quantum level.

Dark Matters Before The Big Bang?

Using a simple, new mathematical framework, Dr. Tenkanen was able to demonstrate that the dark matter possibly formed before the Big Bang. Instead, this invisible material was produced during the epoch of Cosmic Inflation when Space experienced exponential expansion. The faster-than-the-speed-of-light expansion is thought to have resulted in the copious production of certain types of particles termed scalars. The most famous scalar particle to be discovered so far is the Higgs boson.

“We do not know what dark matter is, but if it has anything to do with any scalar particles, it may be older than the Big Bang. With the proposed mathematical scenario, we don’t have to assume new types of interactions between visible and dark matter beyond gravity, which we already know is there,” Dr. Tenkanen explained in the August 8, 2019 Johns Hopkins University Press Release.

The idea that dark matter may have formed before the Big Bang is not new. However, theorists have not been able to devise calculations that support this theory. Dr. Tenkanen’s new study demonstrates that scientists have repeatedly overlooked the simplest possible mathematical model for the origin of dark matter.

The new research also indicates a way to test the origin of dark matter. This can be done by scientists observing the signatures dark matter leaves on the distribution of matter in the Universe.

Dr. Tenkanen continued to note that “While this type of dark matter is too elusive to be found in particle experiments, it can reveal its presence in astronomical observations. We will soon learn more about the origin of dark matter when the Euclid satellite is launched in 2022, It’s going to be very exciting to see what it will reveal about dark matter and if its findings can be used to peek into the times before the Big Bang.”

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