What was it like when dark energy rose to prominence?

When we do exactly that, examining the galaxies, quasars, and other forms of matter that appear billions of light-years away, we’re seeing those objects not as they are today, but as they were in the distant past: back when their light was first emitted. At those earlier times, the Universe was hotter, denser, and filled with smaller, younger, less-evolved galaxies. The light we see from way back in our Universe’s history only arrives at our eyes after journeying across these vast cosmic distances, and only after that light has been stretched by the expanding fabric of space. It’s precisely these early signals, and the process of how that light gets stretched to longer wavelengths — i.e., redshifted — more severely as we look to more and more distant objects, teach us how the Universe has expanded throughout its history. We learned, by collecting that data, that the Universe wasn’t just expanding, but that distant objects appear to speed up, faster and faster, as they mutually recede from one another: the discovery of the accelerated expansion of the Universe. That’s how we discovered dark energy and measured its properties, changing our conception of the Universe forever. Here’s what it was like when dark energy first took over the expanding Universe. <a href="https://medium.com/starts-with-a-bang/what-was-it-like-when-dark-energy-rose-to-prominence-b9b14145aa94">Website</a>