In Search of the Beginning

 

 

Photograph of Orion Nebula courtesy of NASA

by Tom Parisi

While physicists study the origins of the universe, researchers in other fields are making strides as never before in expanding knowledge of our planet, early life on Earth, our ancient human ancestry, and the dawn of civilization. Sometimes armed with sophisticated new tools, these 21st century scientists are trying to crack age-old mysteries. And in some cases, the same professors who lecture at the front of NIU classrooms are among the researchers at the forefront of discovery and debate on our origins.

IN WITH A BANG

Once upon a time, there was no time— or space. Scientists generally agree that “the Big Bang” birthed the universe about 15 billion years ago. Out of this event—at a temperature of nearly a trillion degrees cubed—the building blocks of nature formed. They gathered and spun out matter, energy, space and time, and eventually stars, planets, galaxies, and life itself. From its first instant, the universe has been in a constant state of expansion, cooling, and evolution. Since Albert Einstein’s 1915 Theory of Relativity spawned the Big-Bang theory, scientists have pieced together the puzzle of the universe quite nicely. They now have a good picture, albeit still incomplete, of how the universe unfolded from the first second of time to the present. “For the astronomer, the stars are fossils,” says NIU physicist David Hedin. “The oldest stars point to an occurrence billions of years before even the stars were formed."

Hedin teaches courses ranging from astronomy to quantum physics and is among the NIU faculty members and students who are active researchers at Fermi National Accelerator Laboratory in Batavia. Fermilab is home of the Tevatron, the world’s most powerful particle accelerator. While high-powered telescopes allow astronomers to gaze deeply into the heavens, the Tevatron enables scientists to peer into the depths of the atom.

Back in his college days, Hedin recalls, “I knew I wanted to study the very small or the very big. I went into particle physics because my vision is poor—I couldn’t see real well through a telescope. I didn’t realize then, you’re studying the same thing.”

The similarities between the heavens and the subatomic world are much more than a passing observance. After all, Hedin says, the atoms that make up everything on our planet, from soil and stone to plants and people, were once part of stars. To know the atom is to know the universe.

To understand how Fermilab’s Tevatron works, imagine smashing two Kerry Wood fastballs together head on. Your purpose is to make the baseballs explode and discover what’s inside. With the Tevatron, protons and antiprotons are smashed together instead of baseballs. In the accelerator’s underground, circular ring—with a circumference of four miles—tiny particles zoom at nearly the speed of light, then crash together, producing new particles.

The Tevatron has helped physicists observe the smallest things ever seen, such as quarks, unimaginably tiny particles inside a proton. The accelerator also can re-create the conditions of the early universe–though in a much smaller volume. Creating tiny fireballs of high density and high temperature, physicists produce the particles that were abundant in the early universe, a trillionth of a second after the Big Bang.

Particle collisions are safe

The high energies created in Fermilab’s Tevatron by high-speed particle collisions aren’t dangerous, NIU physicists say. In fact, the same energies can be found in nature. “What Fermi scientists are trying to do is understand features of the natural world that were important at the time of the Big Bang,” says NIU physicist Stephen Martin. “Cosmic rays at the outer edge of our atmosphere are already undergoing collisions of the same type at much, much higher energies than Fermilab can reach.” Particle collisions release an amount of energy that is comparable to the energy needed by a mosquito to fly, according to Fermilab. Because the energy is concentrated in such a small space, however, it has the power to crack protons.


Photo courtesy of Fermilab

Arial view of Fermilab accelerators, with the Main Injector in the foreground and Tevatron in the back. Fermilab welcomes visitors — more information can be found on the Web at www.fnal.gov.

 

With the strength of the Tevatron recently upgraded, Hedin and thousands of scientists from across the globe are trying to identify more of the most basic building blocks of nature. And they believe the mysterious Higgs boson, the Holy Grail of physics, is within their grasp.

Its detection would confirm the existence of the Higgs field, described as a kind of invisible cosmic molasses that permeates the universe. When particles interact with this field, they gain mass. Without mass, all particles would whiz around the universe at the speed of light. Because nothing would stick together, only the tiny particles would exist.

“If we find the Higgs, we’ll know the course of physics has been on the right track for the past 40 years,” Hedin says, adding that the discovery will open new windows of science. “Still, we will need other theories to go further back in time, to the instant the universe began, and to begin to understand the timeless void that might have existed before the universe itself.”

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