This one is a well-documented case. The top candidate is a rocket launch: a SpaceX Falcon 9 carrying Argentina's SAOCOM 1A satellite lifted off from Vandenberg in California about 800 km away, roughly four minutes before the sighting. Right after sunset, the exhaust plume stays lit by sunlight high up while the ground is already dark, which is why it looked like a glowing cloud moving across much of the west. The launch pad lies toward the west, the same direction people were looking. Jupiter was also bright in the west at that time, and it's a plausible second guess for a steady light, but a launch plume explains the cloud shape and the motion better. Local reports at the time agree with this account. This is an archive write-up, so the reasoning comes from the site's records rather than a first-hand report.
From the archive · #c92nfkp2nq6j
Bright light low in the west over Phoenix: the SAOCOM 1A launch
Rocket, not RoswellWant answers like this first in Google? Add WTH Was That? as a preferred source.
Sky Snapshot 7:25 PM, give or take 15 minutes
- Sky
- astronomical twilight
- Moon
- new moon, below the horizon
- Planets up
- Jupiter (6°), Mars (34°), Saturn (28°)
- Bright stars
- Arcturus (west 13°), Vega (northwest 72°), Altair (south 65°), Antares (southwest 12°)
- Weather
- mostly clear, wind 10 km/h
- Space weather
- active (Kp 4.3)
- Sunset
- 6:04 PM
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What people saw
- When
- Oct 7, 2018, 7:25 PM MST
- Where
- Phoenix, Arizona, US
- Looking
- west, low in the sky
- Lasted
- 5 minutes
- Looked like
- one, white/orange, cloud, rising, with a trail
- Sound
- none
On the evening of October 7, 2018, people in Phoenix posted about something bright moving low in the western sky, about 800 km from where it started. Drivers on Interstate 10 pulled over. Guesses ranged from a comet to an alien aircraft, and the mayor of Los Angeles joked that it was "definitely not aliens".
It was a SpaceX Falcon 9 launching Argentina's SAOCOM 1A satellite from Vandenberg in California at 7:21 PM Arizona time, the first time SpaceX landed a booster back at that site. Launches in the hour after sunset are seen across several states because the exhaust is still in sunlight high up.
Sources:
https://www.kpbs.org/news/2018/oct/08/social-media-lights-spacex-satellite-launch
https://technology.inquirer.net/80026/p2fb-definitely-not-aliens-spacex-launch-creates-eerie-cloud-effect-skies-california
From above the area, the way they looked, and what was overhead
The map needs JavaScript. The checks below list everything it shows.
The circle is the area the report came from, rounded to about 10 km. We never show a witness's exact spot.
See it in 3D on the Sky Globe, at the moment it was seen
What it could be
-
Rocket launch Likely100%
- +40Falcon 9 Block 5 | SAOCOM 1A launched from Space Launch Complex 4E, Vandenberg SFB, CA, USA 798 km away, 4 minutes before your sighting.
- +15Timing and twilight are right for a glowing "jellyfish" exhaust plume.
- +15The pad is toward the W, where you were looking.
- +15A glowing cloud, cone or trail is the launch plume.
- +15Rising motion fits a launch.
- +5Plumes stay visible for minutes.
-
Jupiter (bright planet) Likely80%
- +10Jupiter was above the horizon and bright (magnitude -1.8).
- +30It was in the W where you were looking.
- +10Its height above the horizon matches.
- +15Visible for a long time, like a planet.
- +5One steady light.
-
Bright star (twinkling) Possible61%
- +25Arcturus (magnitude -0.05) was 13° up in that direction.
- +10Low in the sky, where a bright star twinkles hardest.
- +8Twinkling is strongest near the horizon.
- +10Stays for a long time.
-
Sky lantern Doesn't fit48%
- +10Night sighting.
- +20Orange flickering glow is a sky lantern.
- +20Drifts slowly with the wind, often rising.
- +5Silent.
- +10Visible for a few minutes before burning out.
- -25A lantern is a glowing dot, not a streak with a trail.
-
Drone Doesn't fit40%
- +10Drones fly low.
- +10Flight times of a few minutes fit.
-
Satellite (ISS or another bright one) Doesn't fit33%
- ·Satellite passes couldn't be checked (orbit data was unavailable).
- +8The duration fits a pass.
What we checked
- Satellites: not checked (orbit data missing)
- Starlink trains: not checked
- Launches: Falcon 9 Block 5 | SAOCOM 1A, 798 km away
- Aircraft: not checked (no flight history feed yet)
- Planets and Moon: Jupiter, Mars, Saturn, and the Moon was down
- Space weather: active (Kp 4.3)
- Weather: mostly clear
- Meteor showers: Orionids
Launch page: SAOCOM 1A, with every city that could see it.
How we worked this out
We took a snapshot of the sky from 15 minutes before to 15 minutes after Oct 8, 2018, 2:25 AM UTC at 33.45, -112.07, and scored 22 possible explanations. Each one starts from how common it is, then gains or loses points for every detail the witness gave and every record we found. The points are listed next to each reason above. "Likely" means 80% or more and "Possible" means 50 to 79%. Anything lower doesn't fit, and if nothing reaches 50%, the case stays unexplained.
Sources: launch schedule from Launch Library 2; planetary Kp from GFZ Potsdam; weather from Open-Meteo; Sun, Moon and planet positions worked out on our server with astronomy-engine. Engine 0.4.0, snapshot v2, worked out Oct 29, 2026, 4:52 PM UTC.
Not available for this report: satellite passes.
Discussion 0 replies
This reply only uses the sky checks above, so it can't claim more than the data shows. Was it helpful?
