We just finished a short video introduction to a new radio array being built in Western Australia called the Murchison Widefield Array. This new radio telescope array is sensitive to frequencies between 80 and 300 MHz (or, in wavelength terms, 1-4 meters), and one of its main science goals is to explore a time in cosmic history called the Epoch of Reionization. It occurred more than 13 billion years ago, when the first stars were beginning to shine out and the first shreds of galaxies were forming. The array will also probe solar and heliospheric events, as well as transient events that occur all over the sky in those wavelength ranges.
Most of the signals in the wavelength range the MWA is sensitive to are masked or covered up by broadcast and other signals that humans use for telecommunications. This makes it very difficult to catch the signals from distant events and objects in space.
In order to catch the signals they want to study, the MWA’s planners chose a location in one of the most radio-quiet places on Earth: Western Australia. The population density there is practically zero when compared to more populated areas, and there’s just not a lot of radio frequency interference to disturb the signals MWA is designed to get.
Scientists in the U.S., Australia, and India are already working with the array, even as it’s being built. The video, which is called MWA: From the Outback to the Cosmos, shows you where the array is and what they hope to do with it. You can also read more about the array at the link at the top of this story.
Later this year I’m going to a meeting in Australia, and while there we’ll be taking a tour of some of the country’s prominent astronomy facilities. One of them is the venerable Parkes Observatory, famous from the 2000 movie The Dish It is a great movie, by the way. One of the few that brings the world of science to the small screen without resorting to swooshing spacecraft bombing each other at faster-than-light speeds. (Nothing wrong with science fiction, I happen to like it a lot myself, but sometimes I like to see things that show the science I know and love, too.)
Parkes Radio Telescope (photo by John Sarkissian, CSIRO Parkes Observatory)
I’m especially interested in the radio telescopes of Australia, since I may be working on a radio astronomy media project over the next couple of years, and want to see as many as possible. Such facilities are fascinating places and I’ve been to a few over the years. Why, there’s one not far from my house in Massachusetts, called Haystack Observatory, and they are who I’ll be working with on my media project.
Haystack Observatory Ionospheric Radars
Another place I have visited a few times over the years is the Very Large Array, in Socorro, New Mexico. It was featured in the movie Contact along with the Arecibo radio telescope in Puerto Rico (which I haven’t been to, but hope to see someday).
Arecibo Observatory in Puerto Rico
Now, in The Dish, the Parkes radio telescope is shown as it was used in 1969 to relay video from the Moon’s surface during the Apollo 11 moonwalk. Of course, the telescope has a longer history than that. Among other things, it has been used to do the Parkes Continuum Surveys, finding and cataloguing various radio sources in the sky. It is currently being used to study pulsars and many other radio sources continually. So, aside from the brief moment of fame this telescope gained in the late 60s, it has been online as an astronomy observatory for many decades.
Haystack Observatory is also a multi-decade achiever in radio astronomy, geodesy (the study of what’s going on with the planet we live on by using radio measurements of the stars), and atmospheric sciences. This observatory’s ongoing mission should provide a rich field from which I can mine for my project.
Finally, VLA and Arecibo are also major contenders in the radio astronomy world. They continually track such sources as pulsars, black holes, and activities at the cores of galaxies. The way they were portrayed in the movie Contact, as search agents for extraterrestrial signals from aliens, is mostly a movie fiction. Arecibo was used some years back to beam a signal out to space, and data from Arecibo is scanned by the Seti@home folks for signals that might be from other civilizations. But, trust me, there’s nobody sitting at VLA with a headset on listening for signals. That’s a nice drama point, though. I happen to think that the better drama lies in the solid achievements these facilities have made to our understanding of the cosmos. And, I look forward to many more years of discoveries from all of the world’s radio astronomy facilities!
very difficult to catch the signals from distant events and objects in space.
