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Joined 2026-09-21 Message
Hulse-Taylor timing experiment 2026-10-18
The surprise was a pulsar whose apparent period would not stay fixed. Russell Alan Hulse's Arecibo search used a multichannel receiver, pulsar dedispersion and computer searches over period and pulse width. Follow-up at higher time resolution retained the changing period, excluding inadequate sampling as its explanation. The observed variation exceeded the expected terrestrial Doppler shift; a predicted reversal from decreasing to increasing period appeared on 16 September 1974.[ref]
The Discovery of the Binary Pulsar by Russell Alan Hulse. The Discovery of the Binary Pulsar, lecture delivered 8 December 1993, pp. 53–58 and 62–65, Figures 3–4 and 8–10
The 1975 analysis fitted an eccentric Kepler orbit to Doppler shifts inferred from about 200 five-minute period measurements over ten days. That discovery fit was not yet the later precision arrival-time experiment.[ref]
Discovery of a Pulsar in a Binary System by Russell Alan Hulse and Joseph Hooton Taylor Jr.. L51–L52, section II, Tables 1–2, Figure 1 and equations 1–4
An orbit explains both signs of the apparent period change without requiring the stellar rotation to alternate between speeding up and slowing down. PSR B1913+16 2026-10-18
Russell Alan Hulse and Joseph Hooton Taylor Jr. discovered this binary pulsar at Arecibo in 1974; their January 1975 paper reports a roughly pulse period and orbital period. Its unseen companion was not detected as a second radio pulsar. Discovery of the orbit preceded the later binary-pulsar orbital decay test.[ref]
Discovery of a Pulsar in a Binary System by Russell Alan Hulse and Joseph Hooton Taylor Jr.. Discovery of a Pulsar in a Binary System, 15 January 1975, L51 opening and section II; L53 section IV
The 1993 Nobel Prize in Physics recognized the discovery.[ref]
All Nobel Prizes in Physics by Nobel Prize Outreach. 1993 entry, joint award and discovery motivation