Blog, Science

The Big Bang & Quantum Physics

This is old an article I wrote for The Meliorist student newspaper about a local physics professor & his recently published paper on cosmology

I had the opportunity to sit down and ask questions for an hour.

Here’s the result of that interview.


 

Two Questions on Life, the Universe & Everything: What is it and where did it come from?

 

For around 50 thousand years humans have sought answers to the essential questions of the universe. Questions which were probably first asked by our prehistoric ancestors, who first wondered, “What is all of this stuff? Where did it come from?”

Many societies have turned to different deities and gods, trying to find a decent explanation. However, In recent history, we have started answering these questions using scientific theories, matching them with our observations.

Science today has many different disciplines that are each devoted to explaining only a small part of what we observe in the natural world. The questions first asked by our ancestors now have specific, specialized disciplines that are determined to find answers.

So… what is our present understanding of the universe?

“Well,” says Professor Saurya Das, a professor of Physics at the University of Lethbridge, “the universe has been expanding.” This has been known since Edwin Hubble presented his findings in the 1920’s, and current research supports this expansion theory now more than ever.

In physics, two of the most influential disciplines are quantum mechanics and cosmology.

The “quantum world” is a term used by scientists to describe the world of the extremely tiny things that make up the universe around us — things such as molecules, light waves and atomic particles. Quantum mechanics studies the composition of the universe: finding an answer to the “what is all this stuff” question.

Conversely, cosmology is the study of the tremendously big things that we observe in outer space – the large-scale structure and evolution of the universe. Cosmology attempts to answer the “where did it come from” question.

“It is no exaggeration to say that physics was reborn in the early 20th-century with the twin revolutions of quantum mechanics and the theory of relativity,” writes physicist Paul Davies in Einstein, the original spin doctor, an article published in the Guardian in 2004. “[Relativity] was famously the brainchild of Albert Einstein, and attained its general form as a theory of gravitation, motion and space-time structure.”

“The general theory of relativity is a great theory,” says Dr. Das. “It is one of the best physics theories ever made. However, it’s completely classical, meaning everything is deterministic and you can predict things exactly—whereas our world is intrinsically quantum, and the quantum world says that things are uncertain or indeterminable and you can’t ever predict things exactly.”

The Big Bang Theory describes the origins of the universe!

Astronomy-Atoms

Dr. Das combines the two disciplines of cosmology and quantum mechanics. The idea of the Big Bang has a rich scientific history that established its roots in the astronomical observations made by astronomer Edwin Hubble in the 1920s.
Using a large telescope, Hubble observed that faraway galaxies are quickly receding from us. He noticed that the further the galaxy was, the faster it was moving away. Hubble saw this as evidence of the universe expanding.

Over the last century, we have gathered exceedingly accurate data and now have a specific rate of expansion. This rate is known as Hubble’s constant. The most recent data from NASA places it in the order of 73.8 kilometres per second per Megaparsec (a Megaparsec is a unit for massive distances – typically used to measure the distance between galaxies).

Because Hubble’s constant is a value of acceleration (velocity over distance), we can actually determine the age of our universe! However, this answer is not completely accurate because the expansion of the universe used to be quicker in the deep past. Nevertheless, it still provides an approximate age of the universe: 13.8 billion years old!

But deep in the confines of the U of L, Dr. Das and his colleagues discuss a new model of the early universe—one that questions the Big Bang and its famous singularity. Das recently coauthored a paper entitled “Cosmology from Quantum Potential.” In this paper, the mathematical ideas of quantum physics are combined with cosmological theories of the Big Bang.

“The new model helps us understand the singularity and it might do away with our notion that the universe is 13.8 billion years old, starting from an infinitely dense point…”

This theory does not dispute the idea of a Big Bang, instead it “systematically computes quantum corrections to classical gravity”— or, in simpler language, it fixes some of the problems that physicists have faced trying to understand singularities.

“Nobody likes singularities.” Says Das, “we can’t do math with them.”

The standard model of the Big Bang says that time and space are created during the first moments of the universe expansion. Physicists are able to accurately describe the seconds after the Big Bang, but, because this is where time is literally created, it is impossible to describe what is happening at the exact moment of the bang (and equally impossible to describe what was happening before it)

A consequence of this new model is that time becomes infinite at the singularity – rather than going down to zero… “Here, there is still expansion, but not from a single point,” says Das. The new model provides a unique perspective: if time is infinite then we can question, what happened before the universe expanded?

Was there another universe before the Big Bang??