The incident occurred between 4:15 p.m. and 4:30 p.m. The cannonball was fired from the bomb range at Camp Parks. It soared 700 yards into a house on Cassata Place, bounced across a road, onto a roof and into a minivan on Springvale Drive.
When the cannonball went through the house, it was traveling at about 1,000 feet per second and whizzed past the bedroom of a sleeping couple.
"They didn't actually hear the cannonball come through the house. What woke them up was the settling of the sheet rock that woke them up," said Sgt. J.D. Nelson from the Alameda Co. Sheriff's Dept.
It punctured the bedroom wall, leaving a 10-inch hole, before bouncing across four lanes of Tassajara Road and into another neighborhood where Ming Jiang says it struck his roof.
"Yeah, that looks like a roof tile," said Jian, who said that his mother was taking care of his 10-month-old son. "She had no idea what was going on. It was a very loud boom and she though a tree fell or maybe a meteor, but it wasn't clear that it was a cannonball that landed on the roof."
It ricocheted across the street and smashed through a minivan's window that Jasbir Gill says he had just parked minutes before impact.
"And looked inside and there was a big cannonball," said Gill. "That was about this big, it was a good five to 10 inches. I was scared. I was lucky my kids weren't in the van."
"This particular myth was to see if other materials could be fired out of a cannon and be as effective as a cannonball," said Nelson.
Instead the MythBusters found out how effective a cannonball is when it misses its target. It was supposed to hit trash cans full of water, but it missed, ripped through a concrete wall and skipped over a hill into the city of Dublin.
The misfire was actually the third cannonball fired on Tuesday. Neighbors say this is where the MythBusters test many of their experiments, so they're used to hearing explosions. Now, investigators say the episode has been put on hold, pending a full investigation.
Earlier Tuesday, the show's official Twitter account retweeted a tweet by Grant Imahara, one of the hosts, saying they would be working with "heavy artillery." Both tweets have since been deleted.