Passage 3 “ Idle speculation” has no place in science, but “speculation” is its very lifeblood, a well-known physicist believes. “ The more fundamental and far-reaching a scientific theory is, the more speculative it is likely to be,” Dr. Michael W. Ovenden, author and lecturer at the University of Glasgow, Scotland, states in his book “Life in the Universe.” Dr. Ovenden says it is erroneous to believe that science is only concerned with “pure facts,” for mere accumulation of facts is a primitive form of science. A mature science tries to arrange facts in significant patterns to see relationships between previously unrelated aspects of the universe. A theory that does not suggest new ways of looking at the universe is not likely to make an important contribution to the development of science. However, it is also important that theories are checked by new experiments and observations. Dr. Ovenden discusses recent discoveries in biology, chemistry and physics that give clues to the possibility of life in the solar system and other star systems. He discusses conditions on Mars, Venus, Jupiter and Saturn, and considers whether or not the same conditions may be found on planets of other stars. Only the planets Venus, Earth, and Mars lie within the temperature zone, about 75,000,000 miles wide, in which life can exist. Venus is covered by a dense layer of clouds which permits no observation of the surface, and the surface temperature of the planet is not known. Mars is colder than Earth, the average temperature being about minus 40 degrees Fahrenheit, compared with plus 59 degrees Fahrenheit as the average for Earth. However, near the Mars poles during the summer season, temperatures may rise to as much as 70 degrees Fahrenheit, whereas winter temperatures may fall to minus 130 degrees Fahrenheit. Because of the extreme difference in the Martian seasons, the only life-forms expected to exist, without a built-in temperature control such as warm-blooded animals and humans have, are those which would stay inactive most of the year. These life-forms may be a kind of vegetation that opens its leaves to the sun in the daytime, stores water and closes its leaves in the night for protection against the cold. Attempts have been made to detect in the spectrum of the dark markings on Mars the absorption lines due to chlorophyll. So far the test has not succeeded. But the infrared spectrum of the Martian markings has been found to be very similar to the spectrum of Earth vegetation when studied at high altitudes.