Listening to the Universe Down Under
BY AWAKE! WRITER IN AUSTRALIA
A KANGAROO suddenly lifts its head, aiming its upright ears at the source of a barely audible noise. The sound is coming from an array of radio telescope antennas that are moving slowly on rails. In the stillness of the countryside, the telescope antennas and the animal both stop, as if frozen in the silence—a curious mixture of nature and science.
Scenes like this are often observed near the Australian town of Narrabri in rural New South Wales at the Australia Telescope National Facility (ATNF). The array of six dishes, five of which are movable and one stationary, is linked with a single 210-foot [64 m] dish located near the town of Parkes and another 72-foot [22 m] dish at nearby Coonabarabran. When these dishes work in sync, they effectively become one giant dish. Even this may be extended by linking up with the telescopes at Tidbinbilla, near Canberra, and at Hobart, Tasmania.
These awesome instruments scan the southern skies—carefully probing their secrets. Why bother to do this? A brochure of the ATNF notes: “A little curiosity leads to great things.”
Unraveling the Secrets of Space
The Parkes telescope was officially opened in October 1961 by Lord De L’Isle, Australia’s then governor-general. He forecast enthusiastically: “This instrument will attract the attention of scientists the world over and its importance in helping to unravel the secrets of space cannot be overestimated.”
The governor-general’s confidence was justified. Opening this facility was a major event in the relatively new science of radio astronomy. The book Beyond Southern Skies notes: “The official opening of the Parkes telescope . . . marked a special day for science in Australia. An idea first conceived ten years earlier, the telescope had taken four years to design and a further two years to construct.”
Dr. David McConnell, officer in charge of the Narrabri Center, told Awake! that the ATNF is the largest such facility in the Southern Hemisphere, adding: “Radio astronomers from many parts of the world come to use the ATNF for scientific research and to study the universe. The unique location of the ATNF provides excellent access to the southern skies for these purposes.”
Seeing What Is Invisible
Unlike optical telescopes, radio telescopes collect information in the form of radio-frequency radiation, which is interpreted and analyzed and then converted into visible images. That is no simple task, for radio signals are extremely feeble.
For example, if the total amount of energy collected from radio signals over the past 40 years by the Parkes telescope were converted to household electricity, it would run a 100-watt light bulb for only a hundred millionth of a second! So states Rick Twardy, scientific services officer at ATNF in Parkes. Once data is collected, it is sent to a huge computer that correlates the combined signals received by the antennas. “The Narrabri facility has a correlator that can process 6,000 million pieces of data per second,” explained McConnell. The results are further processed and then forwarded to ATNF headquarters in Sydney, where they are converted into radio pictures. When these pictures are combined with data obtained from optical telescopes, some of the awesome wonders of the universe are revealed.
The radio telescopes, however, may also work alone for particular research projects. For instance, very faint radio signals, such as those emitted by pulsars, are better received and processed by the larger single dishes, such as the one in Parkes. Hence, this telescope has been instrumental in the discovery of more than half of all the known pulsars in the universe. It was also used to relay pictures of the first moonwalks, and it played a prominent role in the rescue mission of Apollo 13. It was involved in many other discoveries, including the Einstein ring and the wreckage of a supernova, just to give two examples.—See the accompanying box.
Are We Alone?
Although the main work at ATNF is to engage in scientific research and to answer perplexing questions about the universe, a small group of researchers use the ATNF to investigate another question: Are there other civilizations in the universe? This question occupies the minds of researchers known as exobiologists. This term is derived from combining the Greek word exo, meaning “outside,” and bios, meaning “life.”
How can radio telescopes be used to answer this knotty question? Some exobiologists believe that if there were any other civilizations in the universe, they would probably be much older than ours and would thus have knowledge of radio signals and use them to contact earth. A few scientists feel quite optimistic that civilizations, more or less like ours, will be discovered.
But many are not so confident. Some exobiologists even admit that the radio signals they have received, seeming to indicate life in the universe, “have proved to be from one civilisation—our own”! Dr. Ian Morison, chief operations engineer of the British Jodrell Bank radio telescope, said: “Twenty years ago we thought there might be up to a million other civilisations in our galaxy. Now I’m coming increasingly to think that the human race is rather special.”
Special though human civilization may be, we are creating many problems for astronomers and are actually hampering their efforts to collect information from the universe. Listening to the universe is becoming more and more difficult because of the electronic noise we make.
Quiet Please! I Am Trying to Listen
Stronger radio waves, generated by humans, are drowning out the natural radio waves emitted by stellar bodies to the point that “the radio environment has grown deafening,” reports Science News. This interference comes from computers, microwave ovens, cellular telephones, television and radio broadcasts, military radar, air traffic control chatter, and satellite systems. Their signals have to be weeded out from those that come to us from the galaxies in space.
To avoid much of the interference, radio telescopes in Australia and elsewhere in the world are set up in remote locations. Yet, even this may not be far enough away. “Radio astronomers fear they may soon have no quiet spots left for their research. . . . Maybe someday they can hide their telescopes in a place that’s likely to remain quiet: the far side of the moon.” So laments an article in Science News.
Despite all these difficulties, however, ATNF research is revealing details of a marvelous universe that our naked eye would never be able to see. This should give all of us opportunity to reflect on what a wonderful place our earth is in this awesome universe and should fill us with gratitude for the Maker of heaven and earth.
[Box/Pictures on page 16, 17]
WHAT MAKES UP THE UNIVERSE?
Vast numbers of star systems that are held together by gravitational attraction
Radio image of M81 galaxy group
Image courtesy of NRAO/AUI/NSF
Starlike objects that may be the most distant and brightest objects in the universe
Radio image of a quasar six billion light-years away. Its energy source is thought to be a supermassive black hole
Copyright Australia Telescope, CSIRO
Celestial objects, generally believed to be rapidly rotating neutron stars, that emit pulses of radiation, especially radio waves, with a high degree of regularity
In this visible light image, a pulsar is the faint object at the center of the Crab Nebula
Stars that suddenly become thousands of times brighter and then gradually fade to their original intensity
Novas that are millions of times brighter than the sun
Supernova remnant: Radio image in red, X-ray in blue, visible light in green
X-ray (NASA/CXC/SAO)/optical (NASA/HST)/radio (ACTA)
Can one galaxy hide behind another? Not if aligned precisely. The galaxy in the foreground acts like a huge gravitational lens and bends the light or radio waves from the background galaxy into what appear to be rings of light
HST/MERLIN/VLBI National Facility
[Diagram on page 17]
(For fully formatted text, see publication)
Just as X-ray images can show us inside a human body, radio-wave images can help show us the inner workings of the universe
[Picture on page 15]
Top: Five of the six antennas near Narrabri
S. Duff © CSIRO, Australia Telescope National Facility
[Picture on page 15]
The 210-foot dish near Parkes
Photo Copyright: John Sarkissian
[Picture Credit Line on page 15]
J. Masterson © CSIRO, Australia Telescope National Facility