Editor’s Note: Author and Fermilab Senior Scientist Don Lincoln is set to teach “Mysteries of the Universe” from October 13 – 24 for Scientific American‘s Professional Learning Program. We recently talked with Dr. Lincoln about why he became a physicist and his motivations to share what he discovers.

When I was a young boy, I was insatiably curious. I must have driven my parents crazy with my incessant questions about why kittens had fur and why the moon was so much dimmer than the sun. I wanted to know the answer to everything. I still do.

As I grew older, I began to see a pattern. While the answer to the kitten question might have started with biology and the answer to the moon question involved a combination of gravity, fusion and surface reflectivity, these weren’t the final answers. These interim answers led to new questions, which predictably led to atoms, then electrons and nuclei, to protons and neutrons. It became increasingly clear that what I really wanted to know was what Einstein poetically called “God’s thoughts.” No matter your opinion on religion, the meaning of the phrase is clear: I wanted to know nothing less than the ultimate building blocks of the universe and the rules that bind them together. I wanted to know why the world was the way it was.

As I matured intellectually, I came to realize that I wasn’t the first to ask these questions; indeed, they are among the oldest and grandest questions of all. For millennia, they were debated within the confines of philosophy and religion, but this began to change in the mid-1500s as the modern scientific method was being developed. Empirical testing replaced pure logic as the ultimate arbiter of ideas, leading to the approach still followed today.

The Large Hadron Collider at the CERN laboratory is the world's highest energy particle accelerator, a title that it is expected to hold for at least the next two decades. In this facility, scientists collide protons together at nearly the speed of light, generating temperatures at which the very idea of matter becomes hazy. Matter and energy convert back and forth, allowing physicists to gain new insights into the birth of the universe.

For those of us interested in the ultimate questions of the universe, there are really only two fields of interest: cosmology and particle physics. Cosmology deals with the universe as a whole: its birth, evolution and even its death. There is nothing small about cosmology. Particle physics, on the other hand, is concerned with the tiniest objects, the ultimate building blocks of the cosmos, usually studied by smashing two subatomic particles together at prodigious energies.

These two realms–the grandness of the heavens for as far as we can see with our biggest telescopes and objects so unimaginably tiny that we needed to invent an entirely new form of physics to describe them–are intricately intertwined and the fact that we know this is one of the crowning triumphs of modern physics. Through centuries of effort, we now believe that the universe began about 14 billion years ago, in an awe-inspiring explosion that we call the Big Bang. At the moment of creation, the cosmos was much denser and hotter, with matter bathed in energies comparable to those achievable by modern particle accelerators.

Using detectors weighing thousands of tons, particle physicists can record the behavior of matter at unprecedented energies and explore the environment last common at the very moment of creation. It was by studying collisions like the one shown here that scientists came to believe that they had discovered the Higgs boson.

In essence, using a device like the Large Hadron Collider, we can create the conditions of the universe just fractions of a second after the Big Bang.

While I’d love to know the answers to the ultimate questions of creation, these answers still elude us. So I elected to do the next best thing. I became a scientist and joined a multi-generational journey of discovery. It was through centuries of effort by curious men and women that we have come to our current understanding of the cosmos. In turn, my contemporaries and I are working to add to that long tradition, to write our own page in the book of knowledge, a book whose first pages were penned thousands of years ago. While it is unlikely any of us currently alive will see the final answer, for our brief time on Earth, we will follow the path laid out for us by the scientific greats of the past and point the way for those who come after. We must be satisfied by the wisdom that fulfillment is not about the destination, but in the way that we travel.

Like many of my colleagues, I have joined the effort to use the Large Hadron Collider, located at the CERN laboratory in Europe, to better understand the behavior of matter under extreme conditions. The temperatures and pressures generated at the LHC haven’t been common since about a tenth of a trillionth of a second after the universe began. We’ve come a long way since our forebears stared at the stars under a clear and moonless sky and wondered. Being part of this community is how I’ve always wanted to live my life. As kids say nowadays, I am living the dream.

However, for all of the successes of science, you should not think that we’ve understood everything. Far from it. There are many questions for which we don’t know the answer. For instance, we know that ordinary matter makes up only about 4 percent of the matter and energy in the universe. We don’t understand why our universe is made of matter, when we make matter and antimatter in equal quantities. While our current understanding would awe the best scientific minds of a century ago, there are certainly plenty of mysteries left for future generations. If you’re the sort who pestered your parents with questions about kittens and the moon, come join my colleagues and me. You’ll be among friends.