Parts of California, Nevada, and Utah were treated to an unusual space show Wednesday night when what appeared to be a giant fireball streaked across the sky.
YouTube user Ray Remigio caught the shimmering, weirdly slow-moving object on video:
The National Weather Service ruled out any weather-related issues pretty soon after reports began coming in.
Onlookers guessed it could be a meteor, since the Delta Aquarids shower is happening now and due to peak Thursday and Friday evenings.
But the source of the fireball is way weirder.
Phil Plait, an astronomer who writes for Slate, thought something seemed off about that explanation, as he explained on Twitter:
Hearing there was a meteor-like event over western CO and Utah. Video looks like space debris re-entering. https://t.co/FqQ9M1iV8g
- Phil Plait (@BadAstronomer) July 28, 2016#Meteor over western US almost definitely human space debris like a rocket booster or the like. Slow moving and broke apart.
- Phil Plait (@BadAstronomer) July 28, 2016And Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, soon had all the details on what was happening:
Observation reports from Utah indicate the second stage from the first Chang Zheng 7 rocket, launched Jun 25, reentered at 0440 UTC
- Jonathan McDowell (@planet4589) July 28, 2016The time "0440 UTC" is the equivalent of 12:40 a.m. on the US East Coast, or 9:40 p.m. on the West Coast. The identification was later confirmed by orbit-tracking groups.
This was the first time that China's space program launched this particular type of rocket. China is planning to use the rocket on future missions to carry astronauts to the space station they want to launch later this year.
But it turns out things that have been sent into space fall back through Earth's atmosphere and burn up pretty regularly. This was just larger than most.
So far in 2016 there have been 25 reentries of objects massing 1 ton or more. But objects of 5 ton+ class like this are rare.
- Jonathan McDowell (@planet4589) July 28, 2016And the incident wasn't even the largest example this year, according to McDowell:
Only bigger reentry so far this year was a Russian Zenit rocket stage that came down over Vietnam on New Year's Day
- Jonathan McDowell (@planet4589) July 28, 2016In fact, there may be as many as one fireball every night somewhere on Earth. But usually just due to pure chance these things aren't seen - they happen over oceans or where there's no one around.
The Los Angeles Times reports that during the fireball sighting, the rocket piece was probably moving at about 18,000 mph some 50 miles above the ground.