What were those lights in the sky above Northern California? Experts say space junk.

SACRAMENTO, Calif. — Folks out celebrating Saint Patrick's Day or enjoying the start to their weekend in Northern California got a cosmic show Friday night when streaks of light soared across the sky. 

Viewers from all across the region sent us photos and videos all asking ‘what is this?’ ABC10 looked into it.

Jonathan McDowell is an Astrophysicist at the Harvard–Smithsonian Center for Astrophysics and says he is at least 99.9% sure this was space junk from a 2009 launch of ICS-EF.

ICS-EF, also knows as the Inter-orbit Communication System-Exposed Facility, is a Japanese intercommunications network between Kibo and the Tsukuba Space Center, according to Robert Lunsford from the American Meteor Society.

“This was pieces of a package that was jettisoned from a space station about 3 years ago,” said McDowell. “It was moving at about 17,000 mph… What you're seeing is it broken into pieces about 40 miles up [in the sky].”

This communications box has been on the Space Force and astrophysicists radars for quite some time, but McDowell says no warnings were issued due to the guessing nature of where it would come in.

"We knew that this thing was going to reenter sometime this weekend, but we didn't know where," said McDowell. "If you predict Australia and it comes down in California, you look pretty silly. So, you just can't predict these uncontrolled reentries well enough to make useful warnings for people."

Trajectory tracking expected one of the possible reentry spots to be over Chico. The streaks were seen around 9:30 p.m. from the Bay Area up to Shingle Springs, according to our viewers. 

McDowell says it was visible from so far away because of how high in the sky it was. For reference, an airplane usually flies between 6 and 8 miles off the ground while this was visible from about 40 miles up. 

He says this isn't rare and happens a lot more than people realize. 

"The Space Force is tracking 20,000 objects orbiting the Earth like that,"  said McDowell. "We get reentries like this every week, somewhere in the world."

So will it hit the ground? Hurt anyone? Maybe, but not likely, according to McDowell.

“It will probably melt entirely, but a few bits could reach the ground in Yosemite,” he said. "There are many other things you should lose sleep over before you start worrying about getting hit by space debris."

The Space Force and NASA could not immediately be reached by ABC10 Saturday.

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