Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach’s principle, governed by Einstein’s general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive \documentclass[12pt]{minimal}
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\begin{document}$\ddot{M}(t) > 0$\end{document}. For a constant deceleration parameter \documentclass[12pt]{minimal}
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\begin{document}$q = -M(t) \ddot{M}(t)/\dot{M}(t) \sim-0.6$\end{document}, we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χred∼1.0012. The expansion and acceleration of black hole universe are driven by external energy.
