What Is Dark Matter?

In ancient time, map makers had a problem. Their job was to define the lands of the world but there was much undiscovered…so what to do with all that unknown land? The cartographers settled upon a device to use; they wrote “Terra incognita”, Latin for “unknown lands” on the maps and went to lunch. In much the same way astronomers today trying to map out the known universe and coming across matter and energy they cannot define have settled upon the terms Dark Matter and Dark Energy.

One of the major differences here, of course, is that our understanding of the universe and what we find within it is growing exponentially, and so we may be able to unlock the secrets of dark matter. Until that time, however, it remains a mystery, as does its counter part, the even less understood dark energy.

What is Dark Matter?

What dark matter is, is the question. What we call dark matter is matter that does not reflect the electromagnetic spectrum, and thus is unobservable. Great gaps in the volume of space and the universe exist that do not reflect the electromagnetic spectrum—in fact, there is more dark matter than there is not, and much, much more dark energy than anything else.

Who Discovered Dark Matter?

The first person to float a theory on dark matter was a Swiss astrophysicist working out of Caltech, the California Institute of Technology, in 1933. Fritz Zwicky was studying the Coma cluster of galaxies—a grouping together of individual galaxies enveloped in an enormous hot gas cloud- when he discovered evidence of unseen mass.

From just what could be observed Zwicky determined that there was missing mass- that the sum total of matter and energy in the cluster could not account for its total mass. He thus determined there must be some form of mass that could not be observed, and so dark matter was discovered.

From here, astronomers applied this idea to their understanding and measurements of the universe and made a few more interesting discoveries—or theories, as part of the problem with dark matter and dark energy is that it is unobservable. Dark energy was discovered, and then the entire theoretical mass of the universe was calculated using these ideas.

Where Is Everything In THe Universe?

It was determined that the entire sum of matter in the universe, the physical universe of stars and planets and the like, was only 0.4 percent of the total mass of the universe. A further 3.6 percent was made up of interstellar gas. Dark matter was determined to fill 23 percent of the total mass of the universe, leaving the intriguing dark energy to fill the remaining 73 percent.

Final Thoughts On Dark Matter

The very origin of the term dark matter leads many to consider it simply a label for the unknown. Is there only one type of matter that is “dark matter”, or are their many forms of matter that are unobservable to humans, or an infinite amount? Scientists and astronomers continue to use the label with the understanding that they are not one hundred percent sure of what the label itself actually means.

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