Move to America
In 1955, I had attended a cosmic ray conference in Mexico, and I took a swing through the United States on the way back. My first stop in the USA was at the Mount Wilson and Palomar Observatories Pasadena where I was to meet again with Walter Baade, the highly successful astronomer and observer at the 200-in. telescope. The year before, I had discussed the problem of the Crab Nebula with him. This patch of milky nebulosity in our galaxy had been an interesting enigma to astronomers for some time, since the origin of the light from it could not be identified. There were some stars within the patch, but none sufficiently bright to cause a total light emission from the nebula that was judged to be about 100,000 times the output of the Sun. The Dutch astronomers Jan Oort and Theodore Walraven had just published (1956) a surprising new observation, namely, that the light from this nebula was strongly polarized. They gave a figure of approximately 6% polarization, which was high compared with other astronomical objects. They used a novel photometer attached to the 13-in. photographic telescope at Leiden Observatory, and they had been able to take only the light from the entire nebula for this observation, not from any specific part. I told Baade that I could not understand any mechanism that would make an overall polarization, but I could understand that perhaps the radiation came from fast electrons spiraling in magnetic fields. The theory of this effect (known as synchrotron radiation, first seen in particle accelerators) had been worked out initially by Hannes Alfven and Nicolai Herlofson in Norway. It seemed to me that it could apply to this case.