Fancy acronyms are a big deal these days. It will consist of a closed array of 512 six-meter dishes. It will largely partner CHIME (Canadian Hydrogen Intensity Mapping Experiment) another large radio telescope on our site. CHORD will be used to measure the structure and rates of expansion in the young universe, as well as to detect and study fast radio bursts: very short pulses of radio energy from distant objects. These pulses are unpredictable and can come from anywhere in the sky. CHORD will have the very useful ability to image much of the sky above DRAO in near real time, with a very high level of detail. For much of our astronomical history, we thought that overall, things in the universe beyond the solar system happened quite slowly. Even supernovae: the explosions of aging giant stars, and young: other, smaller-scale stellar explosions occur over days to weeks to months. Similarly, pulsars are objects that, once discovered, sit in the sky in a known position, pulsing away. These objects are spinning neutron stars, which emit beams of radio waves. When one of these rays passes us by, we see a flash of radio waves, just as we see a flash of light when the beam from a lighthouse passes us. However, now we find things flashing at us unpredictably from different parts of the sky. The only way we “see” them is if we happen to be looking in the right direction at the right time. Fast radio bursts are almost certainly not the only transient and unpredictable things happening in the universe, and the only way to really find out is to design entirely new types of radio telescopes. Traditional radio telescopes, such as the 87m dish at Jodrell Bank in the UK, or the 26m dish at our observatory, can ‘see’ radio waves coming from a single, small patch of sky. The bigger the dish, the higher the sensitivity, the smaller that piece of sky will see. This is great for accurately measuring known sources, but creating a radio image requires patiently scanning the dish across the area of interest, recording the radio brightness of each small patch of sky, and then combining all that data to create a image. If something happens elsewhere in the sky, the big dish won’t see it. What is required is a large array of small plates. The smaller the dish, the bigger the piece of sky it sees. The larger the panel, the higher the level of detail will be in that image. We can make detailed images of large areas of the sky in a single snapshot. We’ll know pretty quickly if anything weird comes up. Although such instruments have been dreamed of for years, they are only now becoming technically feasible. For example, CHORD will use 512 six-meter dishes. We need to know how to mass produce dishes in a way that keeps costs to a minimum. Each dish will need a complete radio receiver system. Fortunately, thanks in large part to consumer electronics. these are becoming much less expensive than they used to be. Finally, 512 radio telescopes, all operating simultaneously will produce a tsunami of data. Now, again, thanks to the increasing power and decreasing cost of digital electronics, we can build machines that can handle it. DRAO has an established track record in developing these machines. A dream of mine was to look at a large high-resolution screen and see the various radio objects and the Milky Way as it passes overhead, just like when we camp in the woods, we can lie on our backs and look at the stars. It won’t be long now. ————— Venus is low in the dawn glow and to her right, find Mars, Jupiter and then Saturn. The moon will be full on the 13th. It will be almost closer to Earth, so it will appear a little bigger in the sky. Ken Tapping is an astronomer at the National Research Council’s Radio Astrophysical Observatory near Penticton.
