A chunk of ice dropped out of the sky and left a huge hole in the ground this weekend at Oakland's Bushrod Park in California, and not even astronomy experts know where it came from.
Witnesses said it sounded as if someone had dropped a liter of Coca-Cola out of a 10-story building -- and the ice chunk had left behind a big hole.
The ice fell in a populated area near the city border between Berkeley and Oakland, but it didn't hit anything other than an empty lot.
Jacek Purat, a witness to the falling ice, grabbed a piece and is storing it in his freezer. He says it came out of the southwestern sky, slammed into the ground and exploded into pieces.
"A huge chunk of grass was dirt, flew all the way high up over the wires and then splashed in the middle of Shattuck," Purat said.
It burrowed about two-and-a-half feet into the ground, where Oakland firefighters retrieved it.
"They just pulled it out and threw it on the sidewalk and it broke into pieces," Purat said.
Ron Wilson, an aviation consultant for ABC7/KGO-TV in San Francisco, said it probably didn't come from an aircraft. He believes the only possible way it could have come from an airplane is if the plane's valve for freshwater had leaked at a high elevation.
"That sometimes leaks, and that will build and build and form a good chunk of ice," Wilson said.
The other possibility is that it is a chunk of ice from space.
"It's very unlikely for a piece of a comet to make it down to our surface, mainly because of the shock waves it encounters as it's entering our atmosphere," said Ryan Diduck at the Chabot Space and Science Center.
If the ice contains chlorine, it more than likely came from an airplane's freshwater tank. If not, scientists would like to see if it contains impurities from space that make up the solar system, like dust and dirt.
"It produced some little bit of inflammation, sensation of the tips of your fingers as if it had a little bit acid maybe or something like that," Purat said.
So far, no one has asked to analyze Mr. Purat 's chunk of mysterious ice.
This story was reported by affiliate ABC7/KGO-TV in San Francisco.