A large meteor streaked across the night sky Wednesday night and was seen and heard throughout the Bay Area.
Sky observers took to social media to report that they had seen a bright fireball with hues of red and orange break up overhead shortly before 8 p.m., accompanied by a loud boom. The sound was so loud, some residents reported it shook their homes, making them think it may be an earthquake.
Jonathan Braidman, astronomy instructor at Oakland's Chabot Space and Science Center, said the meteor likely hit the Earth around the Martinez Hills and was roughly the size of a car when it broke up over the Bay Area. Braidman said that hikers may be able to find small pieces of the meteor, called meteorites once they land on Earth, in the hills north of Martinez.
Meteors are hunks of rock and metal that have broken off from asteroids and fallen from space, breaking up as they enter Earth's atmosphere. Braidman said that the meteors hit the upper layer of Earth's atmosphere traveling 25,000 mph or more, but the atmosphere slows them down and breaks them up so that when they hit the ground they are only traveling between 200 and 400 mph.
Wednesday night's meteor appeared for about four or five seconds and was traveling fairly slow compared to some other meteors, indicating it was probably relatively large. But the boom that residents heard was a sonic boom, caused by the falling object traveling faster than the speed of sound, and was probably moving at over 1,000 mph, Braidman said.
Braidman said that the meteor is not at all related to the Orionid meteor shower expected to peak over Saturday night and Sunday morning. A meteor shower is actually not an accurate name for this weekend's phenomenon, Braidman said, and that the "shooting stars" that stargazers will see this weekend are in fact small pieces of comet.
The Orionid phenomenon is predictable because it occurs when Earth passes through the trail of Halley's Comet, but Wednesday night's meteor sighting was far less predictable, despite that as much as 15,000 tons of material falls from space each year.
"Even though this kind of thing happens often, it's pretty rare for people to see it," Braidman said.
He said that often such material may not fall in a populated area, potentially just falling into the middle of the ocean. But stargazers can increase their chances of seeing a meteor or other astronomical phenomenon by going somewhere dark, away from city lights.
The Chabot Space and Science Center offers two free public star viewings weekly on Friday and Saturday nights starting at 7:30 p.m. In addition to this weekend's Orionid shower, viewers can also catch glimpses of Jupiter, the Moon and nebulae there. The observatory is located at 10000 Skyline Blvd. in the Oakland Hills.
Sightings of Wednesday night's meteor were reported throughout the Bay Area from Santa Cruz to San Jose, Oakland, Pacifica, Daly City and Sausalito. There was also a reported sighting in Davis.