Some Kansas State University professors are at one of those frontiers, as they explore the world of the "top quark," the latest mystery in the world of physics.
Protons and neutrons form the nuclei of atoms, but they aren't the smallest objects in the universe. Protons and neutrons themselves are composed of "quarks," the very basic things that make up matter.
There are six types of quarks. When the universe was created, physicists believe, all six quarks existed naturally. After time, only the lightest two remained. Those two, the up quark and down quark, are what matter is composed of. The other four have to be created artificially. Regina Demina, assistant professor of physics at K-State, was part of a group that in 1995 discovered the last - and by far the most massive - quark. It is called the top quark.
Size is relative, as the top quark exists at the sub-atomic level, but it is 40 times heavier than any other quark.
"That was quite a surprise. That's why we want to study its properties very carefully. There is something suspicious about this quark. It looks strange. There is no reason why it should be so heavy," Demina said.
Its relationship to other quarks is one of the things K-State physicists are working to discover, along with the reason it doesn't exist naturally. The top quark has only been created in a particle accelerator called the Tevatron, and it decays almost instantly. Scientists also don't know what it decays into.
The Tevatron is located at the Fermi National Accelerator Laboratory near Chicago. The accelerator is a thin, donut-shaped machine several miles in circumference. Protons race around the Tevatron's tunnel at high speeds and collide with anti-protons, which are like protons with a negative electric charge.
K-State physics professor Tim Bolton likens the experiment to a NASCAR race where half the cars race one way around the track and the other half go in the opposite direction.
"We analyze the debris of this NASCAR race," Demina said.
The physicists essentially use energy to create mass. The collisions between anti-protons and protons release a tremendous amount of energy that creates the top quark. Bolton called this the "energy frontier." At one time, the atomic nucleus was the most powerful source of energy known to humankind. Splitting a nucleus provides the propulsion power for many modern navy ships.
"We are increasing the level of energy by a huge amount, by a factor of thousands here," Demina said.
The Tevatron runs 24 hours per day, seven days per week. The accelerator only recently began taking quality data, Demina said. It will take two years to accumulate enough data to draw conclusions. Though they are only hoping to understand the properties of the top quark, the research may eventually benefit people in every day life. The magnetic resonance imaging machine used in medicine and the World Wide Web were results of high-energy physics work, Bolton said.
"There is a consistent history over the last 100 years that when we learn more about the fundamental constituents of the matter, that pays off later. It's always good to learn more about nature," Bolton said.
Three other physicists from K-State - Neville Reay, Ronald Sidwell and Ronald Stanton - are involved in the project. They have received a $715,000 U.S. Department of Energy grant to study the top quark. They are part of a team of scientists from around the world who work on the top quark experiment, but K-State's role is not a small one.
"There is more to us working on this than pulling data. We actually develop and work on a lot of the pieces of these experiments right here. We've brought a lot of high technology to campus," Bolton said. "There is a strong component of the program right here in Manhattan."