NO END IN SIGHT FOR COSMIC RAY ENERGIES. Putting terrestrial accelerators to shame, nature has contrived to imbue some particles with energies greater than 10²⁰ electron volts. But these high-end cosmic ray events---only a mere handful have been recorded so far--- would seem to be at odds with the idea that interactions with the cosmic microwave background act as a sort of universal brake, permitting energies not much above 10^19.6 eV (the so called Griesen-Zasepin-Kuz'min, or GZK, limit). It didn't help that for some time there was a relative scarcity of events in the energy range between 10^19.6 and 10²⁰ eV. But new data reported by the Akeno Giant Air Shower Array (AGASA) collaboration in Japan (Masahiro Takeda et al., mtakeda@icrr.u-tokyo.ac.jp) fills in this gap, strengthening the statistical argument that either the GZK cutoff is not working as planned or that some unexpected process is producing the highest-energy rays.In other words, there seems to be no limit to cosmic ray energy. (Takeda et al., Physical Review Letters, 10 August 1998.)