Image Caption: The Hubble Extreme Deep Field (XDF) was completed in September 2012 and shows the farthest galaxies ever photographed by humans. Each speck of light in the photo is an individual galaxy, some of them as old as 13.2 billion years; the observable universe is estimated to contain more than 200 billion galaxies. Credit: NASA/Wikipedia

What is Cosmology?

I once commented to an acquaintance that I was fascinated by the field of Cosmology, and mused that if I had more time, I would certainly dedicate more time to studying it. Confused, she confessed to being surprised that I would “be so taken with the art of applying makeup.”

Of course, the confusion was that while my friend was familiar with the term “Cosmetology”, the similar sounding Cosmology was new to her.

The general study of Astronomy is quite broad. It encompasses everything from the study of our Sun and the planets, to supernovae and quasars. Therefore, it makes sense to subdivide the field into smaller parts based on the goals of the pursuit.

The field of Cosmology concerns itself with the “big” questions of science: How did the Universe begin? How is it evolving? How will it all end?

Physical Cosmology

Sometimes called Physical Cosmology – to differentiate itself with Religious Cosmology, which has similar goals, but seeks its answers within the faith context – this study utilizes many tools common throughout astronomy and physics to explore these questions.

Even terrestrial experiences, such as particle accelerators, are used by Cosmologists to explore questions about how the contents of the Universe would have behaved and interacted with one another a fraction of a second after the Big Bang.

Formation and Evolution of the Universe

One of the main areas of study within Cosmology is the study of the beginning of our Universe. The leading model is commonly known as the Big Bang Theory – a bit of a misnomer in that the first moments of the Universe are probably best not described as a bang, but rather a rapid expansion, like quickly blowing up a balloon.

Encompassing the earliest days of the newborn Universe, questions of how atoms formed, and what drove the expansion are key.

Fast forwarding in time, we seek to understand how galaxies and clusters formed. One of the largest efforts in Cosmology, researchers in this area want to know how matter interacted early on, and how the Universe became so seemingly smooth.

The Dark Universe

Of course, the big question that everyone – including those outside of science all together – raises revolves around the so-called “dark Universe”. It appears that most – more than 95 percent in fact – of the Universe is made of something other than matter and energy that we can directly see or measure. The nature, formation and interaction of these dark substances may provide the missing pieces to the cosmic puzzle. [See our recent podcasts on Dark Energy and Dark Matter.]

The Fate of it All

It is only human nature to ask how it all ends. There are clues, hidden in the distribution of matter, the rate of expansion of space-time, and background radiation that permeates all of space.

There are still so many unanswered questions, but the picture is always coming more into focus.

Still more are the questions facing Cosmologists; more than can be addressed here. Yet, the work never ceases, and the question for understanding will continue.


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