discovered in the sky. By 1955, it seemed that the number of these sources was significantly higher in the furthest reaches of space. This was the first tentative evidence that the early universe was indeed different from that of the present. However, the results were somewhat controversial as the nature of the radio-sources was not fully understood. More detailed studies undertaken in 1959 and 1962 made it clear that Ryle’s results were essentially correct. By the early 1960s, there was compelling evidence that there is an excess of radio sources at the largest distances observable in clear contradiction with the predictions of the steady-state model. The – importance of this finding was recognized when Ryle and his Cambridge colleague Anthony Hewish became the first astronomers to win the Nobel prize in 1974. An interesting spinoff of the radio-astronomy program was the discovery of quasars – bright sources at extreme redshifts, indicating incredibly powerful sources at extreme distances and (stars that pulsate in an incredibly regular fashion). Again, pulsars – these exotic objects were only seen in the most distant galaxies, suggesting a clear difference between the young universe and the present one. By the mid-1960s, most physicists considered that radio-astronomy offered strong support for the big bang model and cast serious doubt on the steady-state theory. Best of all, as so often happens in science, the new astronomy led to an unexpected discovery that revolutionized the field. The discovery of the cosmic microwave background In 1963, Arno Penzias and Robert Wilson, two physicists at Bell Laboratories in New Jersey who had both trained as astronomers, became interested in the problem of detecting weak signals at radio and microwave wavelengths. This problem had arisen
discovered in the sky. By 1955, it seemed that the number of these sources was significantly higher in the furthest reaches of space. This was the first tentative evidence that the early universe was indeed different from that of the present. However, the results were somewhat controversial as the nature of the radio-sources was not fully understood. More detailed studies undertaken in 1959 and 1962 made it clear that Ryle’s results were essentially correct. By the early 1960s, there was compelling evidence that there is an excess of radio sources at the largest distances observable – in clear contradiction with the predictions of the steady-state model. The importance of this finding was recognized when Ryle and his Cambridge colleague Anthony Hewish became the first astronomers to win the Nobel prize in 1974. An interesting spinoff of the radio-astronomy program was the discovery of quasars – bright sources at extreme redshifts, indicating incredibly powerful sources at extreme distances – and pulsars (stars that pulsate in an incredibly regular fashion). Again, these exotic objects were only seen in the most distant galaxies, suggesting a clear difference between the young universe and the present one. By the mid-1960s, most physicists considered that radio-astronomy offered strong support for the big bang model and cast serious doubt on the steady-state theory. Best of all, as so often happens in science, the new astronomy led to an unexpected discovery that revolutionized the field. The discovery of the cosmic microwave background In 1963, Arno Penzias and Robert Wilson, two physicists at Bell Laboratories in New Jersey who had both trained as astronomers, became interested in the problem of detecting weak signals at radio and microwave wavelengths. This problem had arisen