occasional interference from solar noise static. Radio astronomy developed rapidly afterwards because of the enormous impetus to electronics that the war had produced.

A major stride in radio astronomy occurred in 1951 when E. M. Purcell and H. I. Ewen of Harvard University first observed neutral hydrogen in deep space via the 21-centimeter wavelength radio line. This enabled us for the first time to discover the internal structure of our own Milky Way. Because we live near the plane of the Milky Way, there is so much nearby optical obscuration by dust that we simply cannot see through it to the center or define the shape of our system. Radio astronomy shows that our Milky Way has a spiral structure much like that we observe in other large spiral galaxies. With recent discoveries of new lines emitted by interstellar gas from fundamental atoms and compounds such as hydroxyl (OH), helium (He), water (H2O), ammonia (NH3), carbon (C), formaldehyde (H2CO), carbon monoxide (CO), cyanogen (CN) and HCN, radio is now a vital tool in studying the regions in space where new stars are formed out of interstellar gas and dust.

Radio astronomy has extended our measuring tools to the limits of the optical universe and perhaps further. The quasi stellar objects, or quasars, which appear to be point sources optically, are radio sources of immense energies. We do not understand the source of the energy but suspect that the nuclei of galaxies are controlled by unknown physical processes of unbelievable power.

Because of the development of electronic clocks of extraordinary precision (one second of time error in a million years) it is now possible to use radio telescopes simultaneously over the entire diameter of the Earth to measure angular diameters of distant quasars and other radio sources to accuracies much higher than those possible optically, to about a thousandth of a second of arc.

More recent radio astronomy has led to the discovery of a new form of matter in the remarkable pulsars. These stars are neutron stars, that is, made of neutrons. They are so dense that a volume represented by the ball of a ballpoint pen, if made of this substance, would have a mass of a hundred thousand tons. Such stars may have a total mass comparable to the Sun, but they have diameters of only ten to twenty miles. Some of these stars spin about their axes as fast as thirty times a second. They appear to have been made from super novae outbursts, stars which have undergone catastrophic explosions.

Parallel to radio astronomy, the new science of radar astronomy has developed rapidly in the last two decades. With a powerful radiowave transmitter emitting extremely short pulses of radiation, a large radio antenna can be used effectively as a radar to bounce radio pulses from the Moon, the near planets such as Mercury, Venus, and Mars, and the Sun. While radio astronomy was demonstrating that the surface of Venus is hotter than a roasting oven, radar astronomy demonstrated a slow retrograde rotation of the planet; that is, Venus turns clockwise as seen from the north instead of counter clockwise as is prevalent for both rotation and revolution in the solar system. Huge radars are now mapping the completely cloud-covered surface of Venus and the still partially observed surface of Mars to produce radar pictures with detail comparable to what one can see on the Moon with binoculars. Venus has huge mountain ranges on its surface. The proposed 440-foot diameter radar enclosed fully steerable radio dish has received the most thorough and competent engineering study attempted for any such system. An antenna of great area is required because the radiations we measure in radio astronomy and the reflected signals that we attempt to receive in radar astronomy are unbelievably weak. If set on the strongest radio star a 100-million-million great radio dishes would be required to light up a 100-watt light bulb. The distance from which we can detect a signal of a given intrinsic strength is proportional to the diameter of the radio dish as is the distance of maximum radar detection for an object of a given size and reflectivity. The diameter of the radio "image" varies inversely as the wave length used. The same is true of the beam width of a radar. Greater precision in the surface permits the effective use of the radio-radar antenna at shorter wave lengths and hence with greater resolving power for radio and radar astronomy, the increased range of both again inversely proportional to the wave length. Thus, the largest possible antennas with the greatest precision of surface lead to the greatest power both for radio and radar employment.

From careful theoretical and experimental studies we know that this antenna, protected from the temperature, wind, rain, and other environmental variables, can be made to hold a figure accurate at least to 0.10 inches, so that it can op

erate effectively at a wave length of 5 centimeters, or slightly less than 2 inches. This precision can be held 24 hours a day while exposed radio dishes are distorted by temperature changes on sunny days and by the wind. Analysis shows that still greater precision can actually be attained, certainly for the central 200 feet or more, allowing important experiments at even shorter wave lengths. Experience shows that modern radio-radar antennas are utilized at least half the time at the shortest wave length compatible with their precision. Thus precision is as important as size. New and invaluable results can certainly be obtained with the proposed telescope, particularly in research with lines such as those of hydrogen, OH, water, ammonia, formaldehyde, etc. and from new lines to be discovered for other common molecules.

Recording of the weak radiation from space is now done by integrations over hours of time. Our great electronic computers analyze the data to provide signal strengths from the sources of radar reflections compared to the background noise energy arising from the universe at large, from our magnetosphere or from manmade sources.

The scientists of the United States have led the world by discovering all of the new lines so far known in radio astronomy and by making other major contributions. Yet, we as a nation lag shamefully in the development of large radio antennas. Our largest fully steerable parabola for pure research has a diameter of only 150 feet compared to the new West Germany 100-meter fully steerable dish (100 meters or 327 feet diameter) now being brought into service having been supported financially by the Volkswagen Foundation. The Canadians also have a high-quality 150-foot diameter system. Our largest dish, which is utilized for the Space Program by the National Aeronautics and Space Administration, is 210 feet in diameter, similar to but improved over the earlier dish of the same diameter in use for a number of years in Australia. The great Jodrell Bank 250foot parabola is of a lower quality than these modern antennas but has been in existence for about fifteen years. Plans are now under way in England for a new 400-foot telescope for improved performance.

Basic research is fundamental to the welfare of our country both in the areas of intellectual progress and in applications to modern technology and human welfare, but we are being seriously handicapped by the lack of funds with respect to progress made in other countries that have far fewer resources. The proposed telescope will be a national facility, available for use by other scientists but also available to other departments or activities in the Government for special purposes.

Our scientists have proven competence to forge ahead to new discoveries of a truly exciting nature, the most interesting of which, like the pulsars, will be unpredictable. We know, however, that the great 440-foot dish will enable us to study by radar the satellites of Jupiter, some asteroids, an occasional comet and to study the near terrestrial planets in a detail not achievable for Venus even by space probes. Since radio astronomy appears capable of penetrating farther toward the outskirts of our physical universe than optical methods, the new dish gives us a confident assurance of new discoveries about the nature of the universe, its age, and yet unknown processes that occur today or occurred billions of years ago when perhaps the universe was new. It can provide us with a deeper understanding of the nature of space-time-relativity and the universe in which we live. Applied to the space program it can effectively multiply the payloads of deep space probes by increasing their communication rates with the same power sources. If we ever detect the presence of intelligent beings elsewhere in the universe, we will almost certainly do so by means of a great radio telescope.

Dr. WHIPPLE. Here I have a model which will perhaps clarify the problem of visualizing a 440-foot-in diameter-fully steerable parabolic radio antenna enclosed in a radome, which is here transparent but a section indicates the nature of the structure. The actual dome material would be thinner than the model material and the antenna is designed to point in any direction in the sky.

Mr. THOMPSON. That would be 480 feet in height and 560 feet in diameter?

Dr. WHIPPLE. The dome would be ; yes, sir.

The key to this design is in the radome, because it protects the instrument from the wind, the weather, rain, ice, snow, sleet and so forth, and that means that a very much lighter construction and a more precise construction, can be used for the dish itself. This greatly reduces the cost because much of this comes by the pound. There is precision of operation because there are no distortions due to those meteorological effects.

Likewise, the sun and particularly passing clouds cause temperature changes in such systems. This means that the larger exposed antennas today do not operate with such precision in the daytime as they do at night, because of the changing temperature. This gives you then some idea.

Mr. THOMPSON. Would the interior of this be air conditioned?

Dr. WHIPPLE. It would. It would be kept at a temperature somewhat above the average, near the higher temperature during the day, so that there would be a constant temperature inside the dome.

The engineering is by far the most complete that has been carried out for such an instrument. The National Science Foundation and the NEROC group, which is composed of a number of radio astronomy organizations in New England, particularly headed by the Lincoln Laboratories of Massachusetts Institute of Technology, expended $1.7 million from the National Science Foundation, and have carried the designs for this instrument to a fairly high state, but not to the state of actual blueprints which you can hand to the manufacturer for fixedprice bid. It is the completion of these designs that we are discussing here.

The work has been checked by five major reviewers who have been active in building large complex systems as well as by other scientists of Harvard, of the Smithsonian Astrophysical Observatory and MIT. This would be a national radio facility. It could certainly produce more profound scientific discoveries than those that have been made, because its potential is so great.

Mr. THOMPSON. It might be useful, if you will tell us what radio astronomy is all about. I know it is in your statement.

Dr. WHIPPLE. I should be delighted to. Radio astronomy is a question of time because it is a long story. It is a product of this century. It started in 1932 when Dr. Jansky of the Bell Telephone Laboratories was studying long-range radio transmission from the United States to Europe and discovered that there was noise disturbing communications.

He ascertained by a very ingenious antenna, not as large as this one, but still in its time quite a large antenna, that that radio noise came from the Milky Way, the center of the Milky Way, the center of the Galaxy of which our sun is one of 100 billion stars.

That was the beginning of it. In World War II it was found that noise from the sun was affecting tracking radars that were used in the military. Immediately after World War II, radio astronomy bloomed because the availability of surplus electronic equipment that had been generated during the war made it possible to develop systems.

Radio astronomy observes noises or radio transmissions from regions in space. Some of them are called radio stars, most of which are large gaseous ensembles heated by high temperature sources. It has

discovered new types of sources in space, the most exciting perhaps are the so-called pulsars which are completely a product of radio astronomy because it discovered this noise source with a pulsation rate of about a second which occur in highly concentrated point sources. And now there are perhaps four dozen of those identified in the sky. They turn out to be matter in a new state which had been anticipated by the physicists, but one really didn't expect to find large masses of matter made out of neutrons. A neutron is a building block with a nucleus of matters and the density of such matter is almost beyond comprehension. A solar mass goes into a radius of perhaps 10 or 20 miles. Perhaps an analogy that would be of interest-if you can imagine this density-is taking all the automobiles in the world and stuffing them into a thimble. You would then come out with a density comparable to this matter which we find in pulsars.

Another area of great interest is the so-called quasars or quasi-stellar objects which appear to be galaxies near the edge of the visible universe, perhaps a little farther than we can observe with telescopes, which are indeed galaxies. We think, since a time lapse of some billions of years has taken place in the transmission of the radiation from them, that they represent galaxies in an earlier state of evolution than the one we are in.

As you will recall, galaxies are spiral assemblies containing of the order of 100 billion stars, and in those galaxies we find explosive effects of such magnitude that I have great difficulty in comprehending it or even believing that it is possible.

But to give you some idea of it, these are forces and explosions involving the making not of worlds like the Earth or of suns-the Sun is made up of the equivalent of a third of a million Earths, not suns-but hundreds of millions of suns that are exploding outward in the nuclei of these galaxies.

The general opinion is it sounds like science fiction, but in these galaxies there are new physical forces at work that we do not understand, basic physical principles, processes. And it is information about that sort of phenomenon that we hope to get by using these large dishes that can reach such huge distances in space.

But they have many practical uses, too. If such a dish as this were used to receive the signals from the equipment on deep space probes, scientists could effectively increase the payloads of the space probes by considerable factors. This would result because the large antenna is sensitive to weaker signals; therefore, with a given powerplant, the probe could send out a greater amount of communication in a given time.

Some of the other results in the radar field are of interest, because one can put a transmitter at the focus of this antenna, and then transmit pulsed signals out to nearby objects in space such as, for example, the planet Venus. Radio astronomy showed that, underneath the clouds of this planet, which is almost like the Earth otherwise, the temperature is of the order of 700° or more F., much hotter than a roasting oven. The radar, bouncing pulses off the surface, has shown that there are mountain ranges there and at the present time a map of the surface of the planet Venus is being constructed by radar techniques.