North Korean nuclear worries escalate.

North Korean nuclear worries escalate.

NOBODY KNOWS and everyone is skeptical.

Hello, China.

Officials in Beijing were furious. “China strongly opposes this act,” Hua Chunying, a spokeswoman for the Chinese Ministry of Foreign Affairs, said in unusually harsh remarks at a news conference on Wednesday. “China will firmly push for denuclearization of the Korean Peninsula.” [New York Times]

If it’s not a hydrogen bomb what was it?

Q. What if it was not a hydrogen bomb?

A. When Kim Jong-un, the North’s leader, announced in December that his country had finally developed the technology to build a thermonuclear weapon, experts were skeptical. Some said that North Korea might be preparing to test a “boosted-fission weapon,” more powerful than a traditional atomic bomb. Designers can easily increase the destructive power of an atomic bomb by putting at its core a small amount of tritium, a radioactive form of hydrogen. The Yonhap News Agency of South Korea reported that the government in Seoul was leaning toward the theory of a boosted-fission weapon, “one level away from a hydrogen bomb.”

Council on Foreign Relations maps out the 2016 candidates on North Korea.