When excited, atoms move at impossibly small length and time scales — too small and too fast to have been observed in years past. But as applied and engineering physics professor Joel D. Brock comments in the Feb. 2 issue of Science, a new generation of X-ray sources is allowing scientists to watch atoms move.

He explains that while the XFEL at Stanford would pulse about 100 times per second, Cornell’s ERL could pulse as fast as 1 billion times per second. The machines are used for different kinds of experiments, but both belong to the new generation of X-rays sources for observing atomic activity.

For example, traditional X-ray diffraction technology has long allowed scientists to observe viruses, but through snapshots only — still pictures, limited by the speed of the X-rays.

Using the greatly improved X-ray sources, scientists could someday watch a virus move, see how it grabs on to a cell, and discover why it is harmful. That observation could lead to processes by which to disable the virus.

“We’ve seen the snapshot,” Brock said. “Now let’s see the movie.”

Knowledge lets the genie of invention out of the bottle — and more knowledge.