Herschel’s hole in the sky
Stories from Physics for 11-14 14-16
When William Herschel was observing the night sky, he noted that, in some areas, there appeared to be ‘a hole in the sky’. The nature of these dark areas was not understood till the 1940s when Dutch-American astronomer Bart J. Bok proposed that they were areas of star formation, sometimes called dark nebulae. One such region is the molecular cloud Barnard 68. These compact and spherical dark objects of extremely low temperature, now named Bok globules, are not well understood and remain the subject of research.