Receiving System

Ohm, E. A.

doi:10.1002/j.1538-7305.1961.tb01638.x

Cited by 52 publications

(25 citation statements)

References 8 publications

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“…Dave Hogg describes in FTBB the www.annualreviews.org • Seeing Cosmology Growseveral generations of receiving systems with low-noise traveling wave maser preamplifiers, and he and Arno Penzias and Bob Wilson recall the increasingly awkward problem of reconciling detected and expected system noise. Doroshkevich & Novikov (1964, p. 113) were the first to point out the relevance of the Bell work reported by Ohm (1961) "for experimental checking of the Gamow theory." They were not aware that Bell had an excess noise problem, and the Bell people were not thinking about a sea of microwave radiation.…”

Section: Figurementioning

confidence: 99%

Seeing Cosmology Grow

Peebles

2012

Annu. Rev. Astron. Astrophys.

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The modest science of cosmology I encountered a half century ago has grown into big science. I comment on steps in this development I think I understand because I was there or, in some cases, wish I had been. Wonderful insights-or lucky guesses-and elegant deductions from measurements were accompanied by the usual mix of unlucky guesses and disregard of unwelcome evidence. I say "usual" because I suspect the course of development of any other natural science is similarly erratic. An example in cosmology is Einstein's homogeneous Universe, which was largely accepted as a working hypothesis when there was scant evidence and seriously challenged after we had a reasonable case for homogeneity. Similar mixes of insight and inattention led to the eventual identification of the 3K microwave background, the demonstration that large-scale structure grew by the gravitational instability of the expanding Universe, and the completion of a tight network of cosmological tests. A half century ago, we had little idea what would become of what we were doing in cosmology. We have a better picture now, but I expect there to be more surprises.

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Section: Figurementioning

confidence: 99%

Seeing Cosmology Grow

Peebles

2012

Annu. Rev. Astron. Astrophys.

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“…I bet you thought you knew the answer to this one- Penzias and Wilson (1965)-and perhaps even the particulars of an important nondetection (Ohm 1961). I thought so too.…”

Section: First Detection Of the 3 K Microwave Background Radiationmentioning

confidence: 97%

Astrophysics in 1991

Trimble¹

1992

PASP

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ABSTRACT. Science, notoriously, progresses amoeba-like, thrusting out pseudopods in unpredictable directions and dragging the rest of the body after or, occasionally, retreating in disorder. This review attempts to shine a narrow and not unprejudiced beam of light on areas of astrophysics where the author believes that something interesting happened in 1991. Length scales range from the kilometers of comets to the gigaparsecs of cosmology, and time scales from milliseconds upward. Eight selfcontained sections discuss the surface of Venus, late activity in Comet Halley, convective overshoot, blue stragglers, new examples and kinds of X-ray binaries and recycled pulsars, hard X and y rays from the galactic-center region, microlensing, and biased cold dark matter. The last two sections contain very short descriptions, with references, of a number of items that did not fit into the main sections but seemed a shame to leave out.

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“…And, finally, we return you to Bell Telephone Laboratory, where Edward Ohm is, like Jansky, again scanning the sky to measure backgrounds or noise against which signals will have to be detected, this time from the Echo communications satellite. He used a horn antenna at 2390 MHz and has reported both the process and the results in detail (Ohm, 1961). It is, I think, possible to interpret his numbers in different ways, depending on which portions of the text, figures, and tables you look at.…”

Section: Mapping the Radio Skymentioning

confidence: 99%