Three-quarters of the Universe is dark energy, but nobody knows what it is. Is it an unknown form of energy that fills space, or an illusion caused by extra dimensions of space? Or is it just a flaw in Einstein’s theory of gravity? Proven techniques for investigating these questions are being refined, while new techniques are beginning to be applied to one of the most pressing problems in 21st-century physics. Part 1 discusses supernovae as standard candles.

Finding rare and fleeting cosmic events not only requires the right kind of telescope and camera, it depends on high-performance computing that can pinpoint objects of interest among thousands of sky images while there’s still time for follow-up observations. Caltech and DOE’s NERSC join forces in just such a search, the Palomar Transient Factory.

Generations of Berkeley Lab nuclear scientists have contributed to FRIB, the Facility for Rare Isotope Beams, a $550 million heavy-ion accelerator to study rare nuclear processes that will be built at Michigan State University. Crucial components of FRIB are its ion source, based on the 88-Inch Cyclotron’s record-breaking VENUS, and GRETA, the gamma-ray detector designed and now under construction here. Nuclear Science Division Director James Symons participates in the launch of the new accelerator.

The Nearby Supernova Factory has discovered an efficient method for standardizing the intrinsic brightness and thus the distance to the cosmic milestones known as Type Ia supernovae. The discovery underlines the crucial importance of spectroscopy in the quest to understand dark energy.