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today's world, many things are getting shorter and shorter. Scientists have just measured something incredibly short. They recorded the shortest unit time ever measured. It is called a zeptosecond. This is a tiny, tiny, tiny fraction one second. It is a trillionth a billionth a second. This is a decimal point followed 20 zeros and then a 1. The scientists study atomic physics the Goethe University in Germany. They used special high-tech equipment to measure how long it takes a photon to cross a hydrogen molecule. The scientists said it took 247 zeptoseconds this to happen. This is too small the human eye to see, and the time it takes is too fast humans to sense.

In 1999, Ahmed Zewail, an Egyptian chemist won the Nobel Prize Chemistry measuring the speed which molecules change their shape. He found that one femtosecond equals 0.000000000000001 seconds. This is a decimal point followed 14 zeros and then a 1, or a millionth of a billionth one second. The zeptosecond measures things in terms the speed of light. It is difficult the human mind to understand these measurements. One millisecond is a thousandth one second. This is the time for a neuron the human brain to fire. One nanosecond is one billionth one second. The shortest unit time it may be possible to measure is one Planck. This is a decimal point followed 44 zeros and a 1.

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