One of the advantages of holding hybrid lecture meetings is that we can welcome high quality speakers from far and wide without their having to travel large distances to be with us. A case in point this week when we were joined by Dr Matthew Malek from Sheffield University, with an audience made up of some twenty members at Coleshill Village Hall and others joining in by Zoom from homes or even elsewhere.
Rather like we humans have five senses to experience our environment (sight, smell, taste, touch, hearing) so now has astronomy, because multiple modes of observing have been developed in the last hundred years or so. Up till the middle of the 20th Century, all astronomy was done with visible light, that narrow band of the electromagnetic spectrum that our eyes can detect. The wavelengths that we were later able to use (e.g. infra-red, X-rays, radio waves) expanded our range of tools in the latter part of the last century. The study of the Cosmic Microwave Background opened another window on the universe to astronomers.
From the late 20th Century, yet more tools became available following the development of new types of observatory. For example, the IceCube Observatory is an ultra-high-energy neutrino observatory at the Amundsen–Scott South Pole Station in Antarctica. So energetic are these particles that the Earth itself is used as an absorber – accordingly neutrinos from the northern hemisphere are detected in the southern hemisphere and vice versa. Other neutrino detectors are in a mountain in Japan, in the Mediterranean and in Lake Baikal.
The Pierre Auger Observatory, a Lancashire-sized array in Argentina, is designed to detect ultra-high-energy cosmic rays: sub-atomic particles traveling nearly at the speed of light and each with energies beyond 10¹⁸ eV. And, of course we have Gravity Wave detectors (two LIGO instruments in the USA, Virgo in Italy, Kagra in Japan and soon another one in India) – so far over 90 detections have been made. Finally, to add to our array of “senses” we have VERITAS in Arizona for gamma-ray astronomy in the GeV-TeV photon energy range.
All these different technologies glean complimentary data from each mode to give us the best information about our universe. As Dr Malek concluded, “Multi-messenger Astronomy has just begun”
Sandy Giles
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