Immutable rule of newspaper physics: For every Boston Globe action, there’s an equal and apposite Boston Herald reaction.

Case in point: the Globe’s Whitey Bulger’s life in exile lid-ripper, which revealed that Icelandic beauty Anna Bjornsdottir – late of Noxzema and Vidal Sassoon commercials, and a former Santa Monica neighbor of Bulger and his girlfriend Catherine Grieg – “ended one of the longest and most expansive manhunts in FBI history and brought Bulger home to face charges that he had killed 19 people.”

And ended up with Bjornsdottir receiving a $2 million reward.

Which just got the Herald started:

Safety of tipster feared

‘Huge risk’ vs. $2M reward for Whitey

The outing of an Icelandic woman as the snitch who dimed out Southie mobster James “Whitey” Bulger could put her in danger and may have a chilling effect on other witnesses who could think twice before coming forward, former prosecutors warn.

The FBI — which vowed confidentiality to the tipster — also could take a hit if it comes out that the agency was involved in the leak, experts say. The FBI did not return calls yesterday.

There’s at least a half-dozen follow-up stories in those two paragraphs.

Details to follow.