A jellyfish in the sky? SpaceX rocket creates luminous phenomenon

The iridescent streak lit up the Florida sky just after takeoff.

The SpaceX Inspiration4 mission on Wednesday had everyone excited as the historic launch included an all-civilian crew.

But as the rocket launched, what was happening in the sky as it continued toward space? 

Was that an alien? A bomb explosion? The strange plume that followed the rocket would have caught anyone off guard if they had never seen a rocket launch at night. (Spoiler alert: No aliens … that we know of.)

The iridescent streak lit up the Florida sky, and the plume was seen as far north as North Carolina and Virginia. 

So what was it? 

The exhaust plume that followed the rocket is known as a "rocket jellyfish" or "space jellyfish."

While you might think of jellyfish and their bioluminescence, which is the light produced by a chemical reaction within a living organism, it is not totally like that. For these launches at dusk or dawn, the gases released from the rocket creates a glow. The sun illuminates those emitted gases, and it ends up looking like a giant jellyfish in the sky. 

SpaceX captured footage of what that plume looks like up close from a different launch in 2020: 

Other launches have shown more jaw-dropping sights and even look more jellyfish-like.

Or look more like nuclear aliens, if you're like Elon Musk. 

Either way, the perfect conditions created a truly a spectacular sight in last night's sky.