Sykes is the former C.E.O. and Director of the Planetary Science Institute, serving in that capacity from May 1, 2004 to April 30, 2025.

As a Senior Scientist at PSI, he studies asteroids, comets and interplanetary dust, using both ground-based and space-based telescopes, primarily in the thermal infrared. He is the discoverer of cometary dust trails and many extended structures arising from asteroid collisions within the zodiacal cloud.

Sykes is the former Chair of the Division for Planetary Sciences (DPS) of the American Astronomical Society and was made a Fellow of the American Association for the Advancement of Science for his science advocacy. He is a Fellow of the American Astronomical Society. He has been honored with the 2016 Masursky Award by the Division for Planetary Sciences of the American Astronomical Society for outstanding service to planetary science and exploration. He has also been honored by the designation of Minor Planet 4438 Sykes by the International Astronomical Union.

Sykes is also a member of the Arizona Bar and admitted to the Federal District Court of Arizona.

Sykes is retired as a professional musician, having performed as a member of the Arizona Opera Company chorus for more than 30 years. He is a member of the American Guild of Musical Artists.