How do these new Euclid images change our understanding of dark matter and dark energy?

What these images do is to give us a view of both dark matter and dark energy (the term for the unknown source of the universe’s expansion) that is much broader scale than anything we’ve ever seen.

Dark matter, for example, interacts with normal matter via gravity alone. It emits no light. So, the only way we can see it is by looking at the distribution of matter and observing what it does to light via gravity. If we do this on both the large and small scales, we look at how it clumps together, and maybe we’ll be able to discover if that is different from normal matter.

Dark energy is also difficult to study. It seems to affect how the expansion of the universe changes with time, but we have no idea what it is, or how it has evolved in history. This large-scale, 3D view will help us try to understand how dark energy has evolved, whether it has changed with time, and what the relationship of dark energy and dark matter may be.