['Recent', 'astronomical', 'observations', 'of', 'high', 'redshift', 'type', 'Ia', 'supernovae', 'performed', 'by', 'two', 'groups', '[', '1–3', ']', 'as', 'well', 'as', 'the', 'power', 'spectrum', 'of', 'the', 'cosmic', 'microwave', 'background', 'radiation', 'obtained', 'by', 'the', 'BOOMERANG', '[', '4', ']', 'and', 'MAXIMA-1', '[', '5', ']', 'experiments', 'seem', 'to', 'indicate', 'that', 'at', 'present', 'the', 'Universe', 'is', 'in', 'a', 'state', 'of', 'accelerated', 'expansion', '.']