will use its tools to scan the universe, snapping images of galaxies - the oldest ones dating back to those formed ten billion years ago. By probing these cosmic structures, scientists can measure their position and distance to construct a 3D map of galaxies. They can use this to study how the universe expanded and evolved over time.
"There is a tension between the expansion rate as determined by cosmic microwave background measurements, which are sensitive to the conditions in the early universe, 370,000 years after the Big Bang, and supernova measurements, which are sensitive to the conditions in the last few billion years."Objects appear to be moving away from each other at a pace that increases the further they are from each other.
By building a three-dimensional map of objects, spanning across a third of the sky stretching back to ten billion years, cosmologists can study a sliver of the universe and figure out how its structure evolved over time.