**Abstract**

Traditional time-resolved studies typically rely on a pump laser beam that triggers a reaction dynamic in an atom or molecule and is subsequently probed by a probe pulse of photons, electrons or neutrons. This traditional method is reliant on advancements in creating ever shorter probe and pump pulses. The shorter the pulses the higher is the time resolution. In this chapter we would like to present a novel idea that has the potential to achieve 2–3 orders of magnitude higher time resolutions than is possible with laser and electron compression technology. The proposed novel method is to slow down the 'internal clock' of the sample. This can be achieved by accelerating the sample to relativistic speeds, which can be realized in particle accelerators such as cyclotrons and synchrotrons.

**Keywords:** ultrafast science, femtosecond, attosecond, spectroscopy, electron diffraction, molecular dynamics, special relativity
