There is a large suite of scientific evidence that supports the picture of the expanding Universe and the Big Bang, complete with dark energy. The late-time accelerated expansion doesn’t strictly conserve energy, but the presence of a new component to the Universe, known as dark energy, is required to explain what we observe. (Credit: NASA / GSFC)

Dark energy might be neither particle nor field

Everything else in the Universe is either one or the other. For the first time, we may have encountered something fundamentally different.

What is it, at a fundamental level, that makes up the universe? When we ask this question, we typically think about starting with things that we directly…

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Ethan Siegel

Ethan Siegel

The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.