1944 – Born on the 26th of May in Freeport, New York.
1966 – Davidsen finished A.B at Princeton University.
1968 – Commissioned in the US Navy and served as electronics officer and navigator aboard the WW II-vintage destroyer USS Samuel B. Roberts (DD-823), and later as scientific liaison officer at the Naval Research Laboratory, Washington, DC.
1972 – Graduated M.A at University of California, Berkeley.
1975 – Awarded Ph.D. at University of California, Berkeley.
– Joined the Johns Hopkins faculty as an assistant professor.
1976-1980 – Alfred P. Sloan Foundation Fellow.
1979-1981 – He led the Johns Hopkins effort to establish the Space Telescope Science Institute on its Homewood Campus in Baltimore.
1979 – Recipient of Helen B. Warner Prize of the American Astronomical Society.
1980 – He was promoted to Professor of Physics.
1982-1990 – Served on the Space Telescope Institute Council of the Association of Universities for Research in Astronomy.
1984 – Elected a Fellow of the American Association for the Advancement of Science.
1985 – Served as first Director of Center for Astrophysical Sciences.
1989 – Chairman of its Astronomy Section.
1990 – He served for two years as the first chairman of the Space Telescope Users Committee.
1991 – Elected to a five-year term on the university’s Academic Council.
– Awarded the Johns Hopkins University Presidential Citation.
1992 – He was the AURA Board of Directors.
1995 – Discovered the evidence for the existence of a massive black hole in the center of the galaxy M87.
1996 – Fellow of the American Physical Society.
1997 – Davidsen served as Interim Dean of the Faculty of the Krieger School of Arts and Sciences at Johns Hopkins.
1998 – Organized the 20th General Assembly of the International Astronomical Union in Baltimore.
2001 – He died unexpectedly on 19th of July at the age of 57, from a severe lung disorder.