Short version: The Nov. 4 "pinwheel" seen over parts of the U.S. was a sunlit plume from Arianespace's Ariane 6 rocket. A booster release of excess propellant formed a swirling cloud of ice crystals high in the atmosphere that reflected sunlight while the ground remained in Earth's shadow. Derrick Pitts of the Franklin Institute called the display "impressive." Also note: the Leonid meteor shower runs Nov. 3–Dec. 2, peaking Nov. 17, 2025.
Not a UFO: The Nov. 4 'Pinwheel' Was a Sunlit Rocket Plume from Ariane 6
Short version: The Nov. 4 "pinwheel" seen over parts of the U.S. was a sunlit plume from Arianespace's Ariane 6 rocket. A booster release of excess propellant formed a swirling cloud of ice crystals high in the atmosphere that reflected sunlight while the ground remained in Earth's shadow. Derrick Pitts of the Franklin Institute called the display "impressive." Also note: the Leonid meteor shower runs Nov. 3–Dec. 2, peaking Nov. 17, 2025.
13:40, 07.11.2025Science
What people saw on Nov. 4
On the evening of Tuesday, Nov. 4, many observers across the U.S. Northeast reported a striking "pinwheel" or spiral in the sky that quickly prompted social-media speculation — meteor, rare shooting star, or even a UFO.
The real explanation
The display was not extraterrestrial. According to Derrick Pitts, chief astronomer at the Franklin Institute in Philadelphia, the phenomenon was a visible plume produced during a launch of Arianespace's Ariane 6 rocket from the Guiana Space Centre in French Guiana.
"As one of the rocket's boosters released excess fuel, it created a swirling, crystallized plume of exhaust in the upper atmosphere," The Weather Network reported, a description Pitts confirmed after viewing photos of the event.
At high altitudes, released propellant can expand and freeze into fine ice crystals or vapor that spreads into a spiral-shaped cloud. Because the plume formed above the Earth's shadow (the region of space that is dark for observers on the ground), sunlight continued to illuminate it while the surface below was in darkness. That contrast made the plume unusually bright and visible over long distances.
Pitts described the sight as "impressive" and said he hopes such dramatic displays inspire more people to look up and learn about atmospheric and space phenomena.
Context — the Leonids
Separately, EarthSky notes that the Leonid meteor shower runs from Nov. 3 through Dec. 2 and will peak on Nov. 17, 2025. While the Leonids produced an extraordinary meteor storm in 1966, typical yearly rates are roughly 10–15 meteors per hour for casual observers.
Credits: Reporting contributions by Shawn P. Sullivan of the Portsmouth Herald. This article originally appeared in The Providence Journal.