Uncovering the History of Our Universe


An image of the density of dark matter taken from a "slice" of data from the Millennium Simulation. Parts have been zoomed in to show the intricate structures. This is science at its most beautiful!

As long as there has been intelligent life in the universe, there has existed the most fundamental of questions – why?  Where did all of this come from?  Where did we come from?

Most religions have grown (and, more often than not, died) with the purpose of finding answers to these questions.  As humanity matured, we began to turn to science for answers as well, and it has helped us understand many of nature's laws. As a result, we better understand both ourselves and the universe in which we reside.  However, there has always been that major question nagging at the brains of the greatest scientists – where did the universe come from?

To this day, this remains very much a metaphysical question.  Many see this as the limit of science, and believe the origin of the universe is something that can only be explained by the fantastic and the miraculous.  Some still turn to religion for answers, while others choose to simply not ask the question, for they see the true answer as unattainable.  However, for those of us cursed with the curiosity of a scientist, this is simply not enough.  The origin of the universe must be something observable; something that we can test and study.  As it turns out, the scientists seem to be right.

In 1964, a couple of radio astronomers by the names of Arno Penzias and Robert Wilson made a discovery that would rock the foundations of the scientific community.  They observed what came to be known as the Cosmic Microwave Background (CMB). CMB, or radiation left over from the Big Bang, provided extraordinarily strong evidence in favor of the theory, which states that the universe expanded out of an infinitely dense and hot singularity.  (You can read more about CMB and the Big Bang Theory from NASA here.)

Basically, CMB provides a snapshot of the universe as it was shortly after the Big Bang.  At this time, the universe was nearly uniform, but not exactly.  Quantum fluctuations created small variations in its density which, due to gravity, grew in size and would eventually create the first stars and galaxies.

Recently, a tremendous computational effort has been undertaken to simulate the formation and evolution of these first galaxies.  The project is called the Millennium Cosmological Simulation, and is described in more detail here.

As you can see from the image above, the resulting structures can be quite complicated and beautiful.  This is very exciting for theorists such as myself, because it gives us the chance to explore and understand the history of our universe.  In fact, I am using data taken from the Millennium Simulation in my current research project, which I am very excited about.

The goal of my project is to use the data to model the populations of a special type of binary star system (two stars that orbit one another), called the X-ray Binary, over very long timescales.  By comparing our results with observations, we hope to gain insight into the formation and evolutionary paths that existed for these systems billions of years ago, and compare them with our current understanding.

This is only one example of what amounts to a very exciting time for those of us interested in the early history of the universe.  As observational and computational technologies continue to improve, one can expect that many new revelations about the universe will pop up, along with even more new questions.  This is science at its best and most pure, and I, for one, am very proud to be playing a small part in it.

- blog authored by Michael Tremmel


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