Last year, the Dark Energy Spectroscopic Instrument—DESI—made headlines around the world. Its enormous map of the Universe hinted that dark energy—the mysterious something causing the expansion of the Universe to accelerate—might not actually be constant. Last month, another giant cosmology experiment released its final results. The Dark Energy Survey. DES. Its results are intriguing. But did they confirm the DESI measurement? We’ll, let’s see, but there’s also a much more interesting question—Why are completely different scientific studies so much more powerful in combination than any one study on its own? The answer brings us to the heart of what science really is.