1. A method for automatically detecting fires on Earth's surface and atmospheric phenomena in Earth's atmosphere by means of a satellite system, the method comprising: acquiring multi-spectral images of the Earth at different times by means of a multi-spectral satellite sensor, each multi-spectral image being a collection of single-spectral images each associated with a respective wavelength (λ), each single-spectral image being made up of pixels each indicative of a spectral radiance (R λ ) from a respective area of the Earth; computing an adaptive predictive model predicting spectral radiances (R PRD,λ ) at a considered time for considered pixels on the basis of previously acquired spectral radiances (R λ ) of the considered pixels and of spectral radiances (R PRD,λ ) previously predicted for the considered pixels by said adaptive predictive model; comparing acquired spectral radiances (R λ ) of the considered pixels at a considered time with spectral radiances (R PRD,λ ) predicted at the same considered time for the considered pixels by the adaptive predictive model; and detecting a fire in areas of the Earth's surface or an atmospheric phenomenon in areas of the Earth's atmosphere corresponding to the considered pixels on the basis of an outcome of the comparison.