A massive explosion reportedly damaged an Iranian nuclear facility in the city of Isfahan Monday. Simultaneously, satellite images surfaced showing severe damage to a military base outside Tehran from several blasts that killed 30 members of Iran's elite Revolutionary Guard just two weeks ago. One of the dead was Gen. Hassan Moghaddam, who headed up Iran's missile defense program. Why do sites so crucial to Iran's national security and pride keep blowing up? Here are four theories:

1. This is part of a covert war on Iran's nuclear program
The blast at the Isfahan uranium-enrichment facility on Monday was "no accident," an Israeli intelligence official told The Times of London. The source would not confirm or deny whether Israeli agents were behind the incident, but said that "many different parties [are] looking to sabotage, stop or coerce Iran into stopping its nuclear weapons program." Backing up that theory: Two other major explosions have occured at bases associated with the Shahab-3, the medium-range missile that Iran allegedly wants to adapt to carry a nuclear warhead. Also, three Iranian nuclear scientists have been assassinated recently.

2. Israeli agents are trying to goad Tehran into outright war
Monday's explosion had to be the work of Israeli special operations forces, says John Robb at Global Guerrillas. And the aim clearly wasn't to completely destroy Iran's nuclear program — most of the really crucial facilities are in another city, Natanz. "Israel's hawks see Iran as an existential threat to Israel. They want a war with Iran. This is an attempt to make that war happen." And it might be working — shortly after the blast, Iran's client in southern Lebanon, Hezbollah, fired four Katyusha rockets into Israel (no one was hurt), something they hadn't done in more than two years.

3. Iranian exiles are doing the dirty work
Some analysts believe an exile group, the People's Mojaheddin of Iran (MEK) which frequently works with Mossad, are behind the recent detonations, says Richard Spencer in Britain's Telegraph. U.S. commentator Richard Silverstein, "who has a record of revealing information censored inside Israel," reported on his blog that a source had confirmed Monday's blast was a Mossad operation in collaboration with the MEK.

4. Maybe Iran just has bad luck
Tehran, predictably, has its own explanation; it simply denies that anything happened at its uranium enrichment facility. And it claims that the deadly Nov. 12 explosions happened when missiles were being moved. Shahin Ghobadi, a spokesman for the MEK, tells the Telegraph that his organization had "nothing to do, directly or indirectly," with the missile base explosion that killed Gen. Moghaddam. Gobadi says the Revolutionary Guard is known for its "sloppiness," so he was probably just in the wrong place at the wrong time. Iran's Supreme Leader, Ayatollah Ali Khamenei, had ordered Moghaddam to personally oversee the moving of the base's missiles to a new location so they would be safe in the event of an Israeli strike.