A Hα flare (12°N., 49°W.) on 1968 August 23d23h45m was followed by a short-lived type II burst whose dynamic spectrum, as recorded with the Culgoora radio-spectrograph, is shown in Figure 1. The type II burst had split-band structure; the upper band drifted from 130 MHz to 80 MHz, the lower band from 100 MHz to below 80 MHz (at the time the 25-74 MHz band of the spectrograph was less sensitive than the 74-220 MHz). Unusual spectral features can be seen in each split band. The most remarkable one is an absorption feature between 23h52m02s and 23h52m 10s – the depression in the bright type II emission along an ‘inverted U’ (between 120 and 85 MHz). Several other similar, though less marked, absorption features can be found between 23h51m45s and 23h52m30s.

On 1973 March 22 a radio event was observed above the east limb of the Sun with the Culgoora radioheliograph operating at both 80 and 160 MHz. The first stage of this event, a type I storm closely associated with a rising prominence, offers a new insight into the nature of this phenomenon. This storm was followed immediately by a moving type IV burst – the first burst of this kind for which two-dimensional observations are available at two frequencies. The relation between these two stages may help explain the ‘missing hour’ in observations of another moving type IV burst known as ‘Westward Ho’.

A major crisis facing theoretical nuclear astronomers and physicists today is the apparently very low flux of neutrinos emitted by the Sun. Davis et al. report a measurement of 1.5 ± 1 s.n.u. (1 s.n.u. = 10−36 capture/Cl37/sec) which is a factor of 6 or so smaller than the theoretically predicted values. Numerous suggestions, often quite bizarre, have been made to account for the low flux, but so far no convincing explanation has been offered – see Fowler.