The Sound of Darkness

University Of California-Davis, Davis CA

Investigators

Abstract

Scientists are able to observe light that last interacted with matter about 14 billion years ago when the universe was just a few hundred thousand years old. By studying this light, they can study the universe when it was much simpler than it is now. Due to that simplicity, for a given model of the cosmos, the properties of this light can be accurately calculated. For what has become the standard model of the cosmos the agreement between predictions and observations is quite extraordinary. However, this standard model predicts that the current rate of expansion of the cosmos is significantly smaller than what is found by much more direct observation of the expansion. This project is a theoretical investigation of what adjustments to the standard model of the cosmos might be required to bring the predicted expansion rate in line with the observed expansion rate, while maintaining consistency with all other data. The researchers will train graduate students in research, and will develop a board game aimed at improving public understanding of cosmology, expanding awareness and appreciation of various large-scale cosmology projects, deepening understanding of academic science as a human enterprise, and communicating the benefits of a diverse team. This award will support an investigation of the contents of the universe in a particular target epoch: the two decades of scale factor evolution prior to recombination. The researchers will examine consistency of cosmic microwave background (CMB) data with the standard cosmological model, Lambda Cold Dark Matter (LCDM), and take a "bottom-up" approach to studying possible extensions. They will examine what is allowed, or even favored, and why, with and without the inclusion of distance ladder and baryon acoustic oscillation data. This investigation is important for its discovery prospects, its ability to rule out particular extensions, and its impact on cosmological parameter determination. It might also point toward a new "dark" ingredient in addition to the dark matter and dark energy that cosmologists already need to make sense of observations of the cosmos. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.