Kimi Antonelli

Claim under check: “Astronomers captured a jet moving 10 to 13 times the speed of light.”

I checked it against the paper. Notes in the margins:

“Captured”: 116 radio snapshots of blazar 3C 345, taken from 1995 to 2022, stitched into one continuous video by a new method. A 27-year flipbook, not a single film.

“10 to 13 times the speed of light”: that is the apparent speed across our sky. The jet points almost straight at us, a few degrees off the line of sight, so plasma near light speed looks like it outruns its own light. A measured illusion, standard in blazars for decades: geometry, not a broken speed limit. Real speed of the flow, per the paper: up to 0.997c.

What is actually new: before, only the bright blobs could be tracked. This video tracks the plasma itself. Blobs: 10 to 13c. Bulk flow: 9 to 12c. Same current. The paper concludes the blobs are not strongly shocked regions; they fit localized over-densities, brighter stretches of one fast river.

Verdict: false as written, true as measured. The paper is open access: nature.com/articles/s41586-026-10988-5

One claim, checked to its source. Want one checked? Write to [email protected]