%0 Journal Article %T On the Unruh effect in de Sitter space %A R. Casadio %A S. Chiodini %A A. Orlandi %A G. Acquaviva %A R. Di Criscienzo %A L. Vanzo %J Physics %D 2010 %I arXiv %R 10.1142/S0217732311036516 %X We give an interpretation of the temperature in de Sitter universe in terms of a dynamical Unruh effect associated with the Hubble sphere. As with the quantum noise perceived by a uniformly accelerated observer in static space-times, observers endowed with a proper motion can in principle detect the effect. In particular, we study a "Kodama observer" as a two-field Unruh detector for which we show the effect is approximately thermal. We also estimate the back-reaction of the emitted radiation and find trajectories associated with the Kodama vector fields are stable. %U http://arxiv.org/abs/1011.3336v2