Scientists claim they have measured the shortest interval of time ever.
Researchers used short pulses of laser light to produce images of electrons leaving atoms and recorded what happened to within 100 attoseconds.
To imagine how long this is, if 100 attoseconds is stretched so that it lasts one second, one second would last 300 million years on the same scale.
Scientists used the technique to record the dynamics of electrons in atoms and report their findings in Nature.
The research team employed extreme ultraviolet (XUV) light pulses to excite atoms, prompting them to emit electrons, the small negatively charged particles that are a fundamental part of every atom.
"We accelerate the electrons spinning around the nucleus. Some pick up so much energy that they leave the atoms forever," Professor Ferenc Krausz, of the Technische Universitat Wien, in Austria, told BBC News Online.
At the same time, the scientists used a device called a Few-Cycle Laser to capture "tomographic images" of these electrons that gave information about how they behaved with time.
This allowed the scientists to distinguish events within 100 attoseconds, the shortest interval of time ever recorded.
An attosecond is one quintillionth (10 to the power of minus 18) of a second
Caesium atomic clocks are accurate to one second over many millions of years.