American Scientist

The universe exists on scales of time and distance that lie entirely outside the range of human experience. It is dominated by two substances—dark matter and dark energy—that we cannot yet create, capture, or even measure in a lab. In the face of our ignorance, relegated as we are to a fleeting moment on one small planet, it may seem an absurd ambition for us to make sense of it all. Yet that is exactly what we cosmologists attempt to do.