Showing papers in "Monthly Notices of the Royal Astronomical Society in 1947"

Spherically Symmetrical Models in General Relativity

Abstract: The field equations of general relativity areapplied to pressure-free spherically symmetrical systemsof particles. The equations of motion are determinedwithout the use of approximations and are compared with the Newtonian equations. The total energyis found to be an important parameter, determining thegeometry of 3-space and the ratio of effectivegravitating to invariant mass. The Doppler shift isdiscussed and is found to contain both the velocity shiftand the Einstein shift combined in a rather complexexpression.

Solar Radio-Noise of 200 Mc./s. and its Relation to Solar Observations

Abstract: Summary The solar radio-noise observing programme on Mount Stromlo is described. Daily means of (a) steady flux, and (b) number of bursts per hour have been plotted against sunspot and geomagnetic data. Both flux level and burst frequency increase during a solar radio-noise storm, and both are closely related to the central meridian passage of sunspots. However, some large sunspot groups do not produce solar noise. No close relation has been, found between the emission from the Sun of (a) radio noise, and (b) those particles which produce geomagnetic storms. No close correlation has been found between short period radio-noise phenomena and solar observations, but there are occasional outbursts of solar noise accompanying the commencements of flares. It is suggested that the noise source is located rather high in the corona. The observation of a noise outburst caused by a flare 37° from the main spot group can be explained if the source is more than 120,000ms. above the Sun's surface. Physical arguments lead to a similar height.