Rocket fans in California may have been disappointed by tonight’s scrub of a Delta 4 Heavy launch from Vandenberg Air Force Base, but they received a nice consolation prize: a fireball that left what looked like a contrail hanging in sunset skies.
The bright squiggle in the sky may have mystified some, but savvy folks who spotted the flash recognized it as the signature of an exploding meteor, also known as a bolide.
It was pure coincidence that the fireball flashed at 5:34 p.m. PT, just before United Launch Alliance called off the launch of a classified spy satellite known as NROL-71 for the National Reconnaissance Office, due to elevated hydrogen levels that were detected during the countdown.
Video views captured from cars traveling in locales including Sacramento, Stockton and the San Francisco Bay Area helped solve the celestial mystery. Here are a few of the best clips:
Sorry for the defroster sound , wtf was this , Meteor ? Rocket ? pic.twitter.com/zNR4h5cPgP
— Richard (@Richifornia) December 20, 2018
The meteor (?) captured on my dashcam. pic.twitter.com/ylZBU0ZM3U
— ari c (@aririn) December 20, 2018
— Mario Billiani ? (@_starbase_) December 20, 2018
Did you see that bright light in the sky? Here's the view from West Sacramento. pic.twitter.com/Q83JMy8PSg
— CBS Sacramento CBS13 (@CBSSacramento) December 20, 2018
And here are more views from social media:
Didn’t get to see #NROL71 go, but a huge bolide appeared in the northwest sky and left a trail! It was about as bright as Venus! Got some snaps of the trail on my DSLR. Definitely fragmented in a boom, which we did not hear, as it was traveling away, SE-to-NW. pic.twitter.com/iBmn7RHJPq
— The Most Random Bowl of Cereal (@jaredhead) December 20, 2018
At least we got to see a huge fireball meteor just before the scrub. This is the sun illuminated trail about 5 minutes after the fall. pic.twitter.com/KxiX34eAs6
— D. Stamos/Helodriver (@SpacecoastPix) December 20, 2018
So what the hell was this? pic.twitter.com/sAUUoJJ36d
— Austin (@agweeds707) December 20, 2018
A bright meteor was visible in the skies over the Bay Area shortly after sunset this evening, leaving a bright trail…
#NorCalMeteor #SoCalMeteor Here's the high altitude clouds from the meteor that impacted over the Pacific Ocean. The dust from the burnt up meteor is lit up by the sun while the ground is in darkness creating a super cool effect. pic.twitter.com/zjfazoym9b
— Oliver Pelham Burn (@opbphotos) December 20, 2018
Alien invasion above San Francisco? Don’t panic that’s probably the exhaust of an airplane still illuminated by the sun high in the atmosphere. But that’s pretty and intriguing. Thanks for your emails. #seti pic.twitter.com/EEzvSShEJr
— Franck Marchis (@AllPlanets) December 20, 2018
SETI Institute senior planetary astronomer Franck Marchis was wrong about the airplane exhaust, but he was right about the intriguing nature of the meteor trail. German science writer Daniel Fischer pulled together a lot of the imagery — and pieced together a sensible explanation:
Not a particularly bright bolide then – but it left an unusual bright "glowing" train hanging in the sky (my timeline is full of pictures of it). My hypothesis: it's debris particles it left high in the atmosphere, still lit by the Sun. Would have been just perfect timing.
— Daniel Fischer (@cosmos4u) December 20, 2018
The NROL-17 launch had to be put off until Dec. 30 at the earliest so that United Launch Alliance could address the Delta 4 Heavy rocket’s accumulation of excess hydrogen.
SpaceX’s scheduled launch of an Air Force GPS III satellite from Florida was also postponed today, due to weather, and it may be postponed again on Thursday for the same reason. But today wasn’t a total washout for rocket fans.
India sent up a GSLV rocket with the Indian Air Force’s GSAT-7A remote-sensing satellite, while Arianespace launched the French CSO-1 spy satellite from its spaceport in French Guiana with a Russian-built Soyuz rocket.
Who knows? Maybe there’ll be another sunset fireball to celebrate a successful Delta 4 Heavy launch — after what are now four postponements.
Fireball sighting reports can be filed with the American Meteor Society, which has already received more than 100 reports (and scores of photos).