From The Times (of London):

Researchers: Asteroid Destroyed Sodom and Gomorrah A clay tablet that has baffled scientists for 150 years has been identified as a witness’s account of the asteroid suspected of being behind the destruction of Sodom and Gomorrah.
Researchers who cracked the cuneiform symbols on the Planisphere tablet believe that it recorded an asteroid thought to have been more than half a mile across.
The tablet, found by Henry Layard in the remains of the library in the royal place at Nineveh in the mid-19th century, is thought to be a 700 B.C. copy of notes made by a Sumerian astronomer watching the night sky.
He referred to the asteroid as a “white stone bowl approaching” and recorded it as it “vigorously swept along.”

Update: Oh, for the record, pretty much everyone — if by everyone you mean various readers — thinks this story is unbelievable. For example:

Interesting……but,
A half-mile-wide asteroid? Hit earth around 700 BC and this is the first we’ve heard about it? There should be lots of geophysical evidence for such a massive event happening so recently.

Update II: Several readers have offered this objection about the above objection:

Jonah, I wanted to point out that your reader has the dates wrong. 700BC refers to the age of the tablet. The event was estimated at 3123 B.C.