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Scientists led by Professor Ferenc Krausz have measured the shortest time interval ever recorded, at 100 attoseconds, using tomographic images to record the state of an electron 100 attoseconds after it left the nucleus of an atom. The measurement was achieved using pulses of extreme ultraviolet laser light. The shortest time interval ever measured is still 28 orders of magnitude larger than the smallest physically significant length of time, Planck time.
The shortest time interval ever measured is 100attoseconds (as), one billionth of a second. The measurement was obtained by a research team led by Professor Ferenc Krausz, of the Technische Universitat Wien in Austria. Scientists used tomographic images to record the state of an electron 100 Actoseconds after it departed from the nucleus of an atom. The electron was ejected by pulses of extreme ultraviolet (XUV) laser light. The shorter the wavelength, the more energy you can pack into an electromagnetic beam, and extreme ultraviolet represents a tiny wavelength of just 10nm-100nm, about the size of a large molecule. The only forms of electromagnetic radiation with shorter wavelengths are X-rays, gamma rays and cosmic rays.
The computer you’re using to access this web page probably runs somewhere over 1 GHz, or gigahertz, which means it’s doing about a billion operations per second. The shortest time interval ever measured, 100attoseconds, could fit into that single instruction about a billion times. 100attoseconds is also the time it takes for light to travel approximately 33 nanometers, and it is no coincidence that the measured time interval is roughly equal to the time it takes for light to travel across the wavelength of an ultraviolet wave extreme. Further probing with X-rays or gamma rays could reduce the shortest time interval measured in the low-attoseconds, and perhaps even in the zeptoseconds (billion trillionths of a second).
While a time interval of 100attoseconds is small, it is still 28 orders of magnitude larger than the smallest physically significant length of time, Planck time. In that tiny time interval, quantum fluctuations make it difficult to distinguish a distinct direction of causality. But at 100attoseconds, atomic interactions are very stable.
There are some biological processes that occur in very low timescales. For example, the pigments in your eye that detect incoming light respond within about 100 femtoseconds (fs), or about 1,000 times longer than the shortest measured interval. Many rapid chemical reactions occur in the femtosecond range. Subatomic events, such as the ejection of the electron from the nucleus as in this experiment, are one of the few observable events that occur on such short time scales.
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