With BP seemingly running out of options to seal the broken oil well in the Gulf of Mexico, many are debating a dramatic last resort — a nuclear bomb. (Watch Adm. Thad Allen discuss the nuclear bomb option.) The Soviet Union successfully sealed up four leaking wells using nuclear warheads during the 1960s and 70s, and with the prospect of oil gushing until at least August, the nuclear option is emerging as a subject of serious debate:

How would a nuclear explosion stop the oil from gushing?
The bomb would be detonated deep underground, in a separate well beneath the sea floor. In theory, the extreme heat generated by the explosion would collapse the well bore, melting surrounding rock into a "glassy plug" that would seal the shaft "much like a huge stopper in a leaky bottle." Nuclear expert Christopher Brownfield tells The Takeaway: "When you're looking at this geological formation with a 15,000 foot narrow 'straw' going through it, it doesn't really take that much to break that 'straw' and seal it off."

Has the technique been tried before?
Yes. The Soviet Union capped four gas wells using nuclear bombs in 1966, 1968 and twice in 1972. Another attempt in 1981 was unsuccessful, likely due to "poor geological data."

So why don't we try it?
There are a few reasons to be cautious. Firstly, the Soviet Union's well explosions were all conducted inland. Creating an underwater explosion to seal off the well would be highly experimental technology, and would not be guaranteed to work. Secondly, the fall-out from a nuclear explosion could create fresh environmental hazards. And thirdly, detonating a nuclear bomb would potentially undermine international anti-nuclear treaties by establishing a new and legitimate "peaceful" use for nukes.

What kind of "fresh environmental hazards" could a nuclear explosion create?
Although the explosion would happen deep underground, radioactive gases could still seep into the Gulf. That said, "it seems a reasonable conjecture that the dissipation of a limited amount of radioactive material across the vast Gulf is preferable to the blanketing of thousands of miles of American coastline in ribbons of tar," says Daniel Foster in the National Review. But the worst case scenario, says Andrew Leonard at Salon, would be a "chain reaction" leading to a massive release of frozen natural gas in the seabed — potentially wiping out most of the life on planet Earth. 

Is the U.S. considering the nuclear option?
A five-man team of nuclear physicists has reportedly been dispatched to the Gulf to look at "outside-the-box" solutions to the spill, but the White House says using a nuclear bomb to stem the flow was not even a possibility. "It's crazy," one senior official told The New York Times.

Could we use a conventional bomb?
Experts warn that the well and its surrounding geology are fragile and a less powerful explosion might open up fissures and make the leak essentially unstoppable. Because of the risks, using any kind of explosive device should be an option of last resort.

Sources: New York Times, Salon, National Review, The Takeaway, Hardball