Luke A. Barnes is a theoretical astrophysicist, cosmologist, and postdoctoral researcher at Western Sydney University.

He received his PhD in Astronomy from the University of Cambridge in 2009.   He is a John Templeton Fellow. He has published papers in the fields of galaxy formation and the fine-tuning of the Universe for life. He is the author, with Geraint Lewis, of A Fortunate Universe: Life in a Finely Tuned Cosmos published by Cambridge University Press. He has also published papers on the philosophy of science, and regularly engages in public outreach through public speaking, articles in the popular press, and social media. He has modeled galaxy formation in a cosmological context with supercomputer simulations, and connected those simulations to observations with modeling of radiative transfer (particularly Lyman alpha emission and absorption) and realistic models of IFU observations.

He has investigated the fine-tuning of the universe for intelligent life, modeling the effect of the cosmological constant on galaxy formation and the effect of alternative nuclear physics on stars. He has contributed to the philosophy of science by considering the challenges of testing multiverse theories using probability theory.