For centuries, people have asked a question perhaps best articulated by the rock band Chicago: Does anybody really know what time it is?

The answer may be no, as attendees at the Dec. 21 installment of the Rockville Science Cafe learned.

People with an interest in good food and scientific discourse have gathered at Branded 72 Pit Barbecue on Gude Drive for barbecue and a new scientific topic each month for the past two years.

Last week, Steven Rolston, a professor and co-director of the Joint Quantum Institute at the University of Maryland, College Park, led a discussion centered on atomic clocks and the democratic nature of time.

It turns out that there is no exactly correct time that appears simultaneously on atomic clocks at bureaus of standards around the world, Rolston said. What we call "the time" is in fact an average of the time showing on those clocks.

In his informal presentation, Rolston also talked about the way that time is used for navigation, including a look at historical methods for measuring longitude and latitude. He rounded out the evening with a brief bit of quantum mechanics (a concept that is a bit too complicated to get into in this space).

The informal science cafe presentations are made by a different person each month. Ralston's reason for participating was simple, he said. "It's very important to engage the public in science," he said. "We live in a technological society and it's all based back to the fundamentals. The more the population knows about science, the better."

The cafes and other science-related activity fall under the auspices of the Rockville Consortium for Science, a nonprofit educational organization founded in 1989. The cafes are planned by the Rockville Science Center and sponsored by Sigma Xi, the nonprofit research society of scientists and engineers. They attract a diverse group that ranges from retired scientists and Sigma Xi members to high school kids attending the lectures for class credit to those who are simply curious about science. Questions are encouraged.

The ultimate goal of those involved in planning and executing the scientific endeavors is to establish a home for a science center in Rockville. That effort is supported by Rockville Mayor Phyllis Marcuccio, who attended the Dec. 21 cafe and assured those gathered that there will be a science center in Rockville someday.

In the meantime, there are like-minded individuals making time for barbecue and atomic clocks.