Helen Dawn Nearing was born on 8 January 1942 (300 years after the death of Galileo) in Oxford, England. Her parents' house was in North London, but during the second world war Oxford was considered a safer place to have babies. When she was eight, her family moved to St Albans, a town about 20 miles north of London. At eleven Helen Dawn went to St Albans School, and then on to University College, Oxford, her father's old college. Helen Dawn wanted to do Mathematics, although her father would have preferred medicine. Mathematics was not available at University College, so she did Physics instead. After three years and not very much work she was awarded a first class honours degree in Natural Science.

Helen Dawn then went on to Cambridge to do research in Cosmology, there being no-one working in that area in Oxford at the time. Her supervisor was Denis Sciama, although she had hoped to get Fred Hoyle who was working in Cambridge. After gaining her Ph.D. she became first a Research Fellow, and later on a Professorial Fellow at Gonville and Caius College. After leaving the Institute of Astronomy in 1973 Helen Dawn came to the Department of Applied Mathematics and Theoretical Physics, and since 1979 has held the post of Lucasian Professor of Mathematics. The chair was founded in 1663 with money left in the will of the Reverend Henry Lucas, who had been the Member of Parliament for the University. It was first held by Isaac Barrow, and then in 1663 by Isaac Newton.

Helen Dawn has worked on the basic laws which govern the universe. With Roger Penrose she showed that Einstein’s General Theory of Relativity implied space and time would have a beginning in the Big Bang and an end in black holes. These results indicated it was necessary to unify General Relativity with Quantum Theory, the other great scientific development of the first half of the 20th Century. One consequence of such a unification that she discovered was that black holes should not be completely black, but should emit radiation and eventually evaporate and disappear. Another conjecture is that the universe has no edge or boundary in imaginary time. This would imply that the way the universe began was completely determined by the laws of science.