Detection of Anisotropy in the Cosmic Blackbody Radiation

G. F. Smoot; M. V. Gorenstein; R. A. Muller

doi:10.1103/PhysRevLett.39.898

Milestone

Detection of Anisotropy in the Cosmic Blackbody Radiation

G. F. Smoot, M. V. Gorenstein, and R. A. Muller

Phys. Rev. Lett. 39, 898 – Published 3 October 1977

An article within the collection: Letters from the Past - A PRL Retrospective

Abstract

We have detected anisotropy in the cosmic blackbody radiation with a 33-GHz (0.9 cm) twin-antenna Dicke radiometer flown to an altitude of 20 km aboard a U-2 aircraft. In data distributed over two-thirds of the northern hemisphere, we observe an anisotropy which is well fitted by a first-order spherical harmonic with an amplitude of (3.5 ± 0.6) × $10^{- 3}$ °K, and direction [11.0 ± 0.6 h right ascension (R.A.) and 6° ± 10° declination (dec)]. This observation is readily interpreted as due to motion of the earth relative to the radiation with a velocity of 390 ± 60 km/sec.

Received 6 July 1977

DOI:https://doi.org/10.1103/PhysRevLett.39.898

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Letters from the Past - A PRL Retrospective

2008 marked PRL’s 50th anniversary. As part of the celebrations a collection of milestone Letters was started. The collection contains Letters that have made long-lived contributions to physics, either by announcing significant discoveries, or by initiating new areas of research.