Cosmic filaments are among the largest structures in the Universe, and they rotate. In a new study that stacked thousands of filaments together, they were observed to be rotating along their filamentary axis, with the average rotation speed approaching ~100 km/s at maximum. (AIP (LEIBNIZ INSTITUTE FOR ASTROPHYSICS POTSDAM)/A. KHALATYAN/J. FOHLMEISTER)

Did We Just Find The Largest Rotating ‘Thing’ In The Universe?

Ethan Siegel
Starts With A Bang!
10 min readJun 22, 2021

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Filaments, hundreds of millions of light-years long, were just caught spinning.

In our own cosmic backyard, everything we see spins, rotates, and revolves in some fashion or other. Our planet (and everything on it) spins about its axis, just like every planet and moon in the Solar System. The moons (including our own) revolve around their parent planet, while the planet-moon systems all revolve around the Sun. The Sun, in turn, like all of the hundreds of billions of stars in the galaxy, orbit around the galactic center, while the entire galaxy itself spins about the central bulge.

On the largest of cosmic scales, however, there’s no observed global rotation. The Universe, for whatever reason, doesn’t appear to have an overall spin or rotation to it, and doesn’t appear to be revolving around anything else. Similarly, the largest observed cosmic structures don’t appear to be spinning, rotating, or revolving around any other structures. But recently, a new study appears to be challenging that, claiming that enormous cosmic filaments — the strands of the cosmic web — appear to be rotating about the filamentary axis itself. This is weird, for sure, but can we explain it? Let’s find out.

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Ethan Siegel
Starts With A Bang!

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