Last night, California was treated to a spectacle like no other.

The sky lit up with a display more reminiscent of a supernova than a Sunday night, sonic booms rang out across neighborhoods, and the mayor of Los Angeles sent out a tweet reassuring residents that what they were seeing was "nope, definitely not aliens."

The cause of all this hullabaloo? A SpaceX Falcon 9 rocket on a journey that would make history.

Taking off from Vandenberg Air Force Base last night (October 7) at about 7.21 pm local time, the Falcon 9's primary goal was to deliver a satellite, the SAOCOM 1A, into orbit for CONAE, the national space agency of Argentina. SAOCOM 1A, as the name implies, is just the first of a group of satellites that will include SAOCOM 1B, and it will be used to monitor natural disasters, crop yields, and soil-moisture levels, according to the BBC.

But it was the second stage of the mission that made the record books, as the rocket's reusable booster came back down to make the first ever land-based landing on the West Coast.

And across the region, spectators watched as the amazing show fired across the sky.

"I watched the launch from Santa Ynez peak, about 40 miles from the base," Joaquin Baldwin told Space. "It was spectacular, the fog lit up and quickly the horizon turned red... It looked as if we were staring into a nebula, with two bright eyes staring back."

Last night marked the 30th landing out of 62 launches for SpaceX, but only the 12th on land. Previous landings, however, have all been at SpaceX's Cape Canaveral base in Florida, where the company made history back in March 2017 with a first-ever second flight for a reusable Falcon 9.

Residents of Los Angeles captured some stunning shots and footage of the rocket's ascent and return.

Even the city's mayor took the time to appreciate the breathtaking display.

Although for some onlookers, the display inspired for terror than awe.

Social media users who didn't know about the launch flocked online to ask about the lights they'd seen in the sky, prompting a massive spike in searches for "UFO" in California.

Listen: while there may be reasons to be optimistic about our chances of making contact with alien life, this is of course another encounter with a clear and obvious explanation. It was just a really, really beautiful rocket launch.