TO THE OUTER LIMITS OF SPACE

Press, Volume XCIX, Issue 29366, 19 November 1960, Page 10

TO THE OUTER LIMITS OF SPACE

Australian Scientists Have New Ideas

(By DAVID BURKE, for Associated Newspapers Feature Services) SYDNEY, November 11. AUSTRALIAN astronomers are to be the first in the world to make contact with the stars almost on the edge of the universe.

“We hope to go close to the fundamental limit, beyond which it is not possible for man to seek,” Dr. Bernard Yarnton Mills, of Sydney University, said this week.

Dr. Mills and his colleagues are designing a giant new radio telescope—a “Mills Cross,” to be built in New South Wales. It will be the largest in the world.

Just how far away is that '‘fundamental limit.” beyond which it will not be possible for man to seek? “Thirty thousand million light years,” Dr Mills said. “Multiply that figure by the speed of light (186,000 miles a second), then by the number of seconds in the year (31,536,000) and you'll have the answer in terms of milage.” Does this mean that man, even if he .built larger and more powerful radio telescopes, will never go beyond the zone which the Australian instrument is to probe? “Larger and later telescopes will pick up stronger, more detailed radiation from the old and very distant regions of the universe,” Dr Mills said. “Ordinary ideas of time and space do not apply in these regions and we must be very careful how words are used to describe them. “In the last small outer parts of the universe (that is, small from our point of view) it is possible that an infinity of worlds lies hidden. Who can say what will be found until the observations are actually made?” Radio Transmissions On the mammoth, sensitive receiver, Dr Mills hopes to' pick up radio transmissions—a natural phenomenon from the stars — that began in space 30,000 million years ago. With it he will test the theories of the very origin of the universe. How? “There are two theories we investigate—the ‘Big Bang' and the ‘Steady State’.” he explained. “The ’Big Bang’ theory says the universe came into being at a particular time and 'has being expanding ever since. “According to the ‘Steady State’ theory, matter is creating continuously, and as the universe expands, more is created to fill the void. “The very great range of the cross will enable us to test both theories. “The number of very weak radio sources we pick up near the limit of the universe—the point beyond which signals cannot be received —will be the determing factor. ‘‘The ‘Steady State’ theory makes very definite predictions about what we should find. If we see these things do exist, it will be very strong evidence that the theory of continuous creation is correct. “If we don’t find them, the ‘Big Bang’ theory will be shown in a more favourable light.”

Dimensions Of “Mills Cross”

At first meeting it is hard for the layman stranger to penetrate the modest, youthful exterior of the man who is an international authority on radio astronomy. He is 40 years old, married, lives at Turramurra, has a son aged four, and daughters three and two.

A graduate of Sydney University in science and engineering, he was a “back-room boy” in the 1940’s—one of the early developers of radar. Six years ago he built his first “cross type” radio telescope at St. Mary’s, New South Wales. It was the most powerful radio tele-

scope in the world at the time: the new project dwarfs it The arms of the first ‘Mills cross' were 500 yards long. In the new model, each arm will measure a mile.

No one has yet worked out how many hudred tons of steel or miles of wiring will be needed to build th? Mills cross. One ingredient is known: 15 acres of chicken wire required for the 40ft wide parabolic reflector running the length of both arms, and reflecting the radio signals on to a central aerial. (“We will use the same sort of chicken wire you buy in a hardware shop.” Dr Mills said. “There is nothing fancy about this part of the construction be - cause we are working on fairly long wave lengths.") About 200 seperate receivers will be installed on the northsouth arm; about 12 on the eastwest arm. The north-south arm is to bo fixed. The east-west arm will swivel to 45 degrees from the vertical. “Tuned-In” The cross will be “tuned-in" to the sun and moon, and to the planets Mercury, Venus. Mars, Jupiter, Saturn, Uranus. Neptune and Pluto. Radiations from the sun (90,000,000 miles away) ’ will be picked up eight minutes later. However the main interest will be in radiation from interstellar matter—the gases between the stars—with a particular interest in one of Dr Mills’s "pets,” the centre of the enormous Milky Way galaxy, 30,000 light years away. Vast Projects The vast projects to examiine the twin theories of creation, study the southern skies and trace cosmic rays, will occupy at least 15 years. Punched tape will record the fundamental output of the cross, to be fed later in to SILLIAC. the University’s electronic brain, for analysis: other records are to be made on graph machines. “We couldn’t carry through the work without SILLIAC." Dr Mills said. “The ‘whole sky’ survey would be impossible without it”

The site of the Mills Cross, though not yet decided is expected to be on either the flat terrain near Lake Geqrge, near Canberra, or somewhere west of the Blue Mountains.

The first section of the cross is to be ready in two years, and the complete instrument in about four years. Working in co-operation with it will be the C.5.1.R.0.'s new 210 ft diameter "dish” now being built at Parkes, Sydney University’s interferometer (for reading the temperature and diameter of the stars) at Narrabri, and the great optical telescopes of the Mt. Stromlo Observatory, near Canberra.

“Because of the fixed nature of the cross, we have to accept some limitations,” Dr Mills said. We are interested in constant sources of radiation—those that do not change with time. “Unlike a flexible ‘dish’ telescope. it will not be used for satellite tracking or rocket or ‘man in space’ projects.” The size of the monster telescope and the exciting new fields it enters more than make up for these restrictions. It will have 10 acres of collecting area compared with the single acre in the world's biggest existing parabolic reflector dish at Jodrell - Bank. England. To build a “steerable” dish the same size as the cross would, in Dr Mills’s own words, cost ‘‘thousands minions,” if it could be done at all.

“There aren’t many fields of science, because of the tremendous . expenses involved, where Australia is in the forefront—but radio astronomy-is one of them,” he said. “Building of the ‘cross’ will ensure that we maintain our position far into the future. It will cost about £300,000. We have £lOO,OOO in hand and we're hoping to raise the rest.