Speaking for myself, I don't put much into this particular asteroid claim, primarily because the article points to
abovetopsecret.com as the source. A lot of what ATS seems discuss are the usual garden variety of wild speculations involving conspiracies, UFOs, etc.
Asteroid Destroyed Sodom and Gomorrah, not God, page 1
Apart from that, there are several problems with the original OP at ATS. There's no indication who supposedly "cracked" the cuneiform symbols. Secondly, whoever came up with the idea, believes the asteroid was about a half mile across. While a space rock that size might not destroy the Earth, something that size could cause widespread destruction and leave an enormous crater that should still be easily visible today. I'm not familiar with any gigantic craters in that part of the world. I would think a half-mile wide meteor would carve out a crater much, much larger than the Barringer Crater (Meteor Crater) in Arizona. That meteor is thought to have been about 150 feet across.
Barringer Meteorite Crater, Impact Theory and Meteor Craters
One area of where Sodom and Gomorrah are thought to be located contains a fairly high level of salt and limestone near the Dea Sea. That makes me think it more likely some kind of volcanic activity might have taken place there at one time. The problem is that the locations of both ancient cities are still unknown. One person seems to think they were at the south end of the Dead Sea, while another thinks they may be located at the north end where some ruins have been uncovered. It's possible these places once existed, but it's also possible they are both fictitious, or could be based on a completely different story, one suggestion is the destruction of some ancient Babylonian city.
Sodom and Gomorrah - Wikipedia, the free encyclopedia