The H-bomb: What is it? Who has it? Why it matters

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(CNN) — North Korea announced Wednesday that it had successfully tested a hydrogen bomb.

If true, it now processes something much more powerful than the weapons it has tested in the past.

The nuclear age is 70 years old and while relatively few nations possess the power, the potential consequences of North Korea upping its nuclear game from a basic atomic bomb to a hydrogen bomb has caught the world’s attention.

Here’s why.

A quick lesson in fission versus fusion

If Pyongyang has mastered the technology, it has made a major step forward in its nuclear capabilities.

The plutonium-based atomic weapons it tested up until this point were powerful enough — the United States dropped them on Japan to end World War II — but a hydrogen bomb made with uranium ups the ante many fold.

Atomic bombs use a process called fission. They split plutonium into smaller atoms, releasing massive amounts of energy

The A-bombs dropped by American forces on Hiroshima and Nagasaki in 1945 killed more than 200,000 people

Hydrogen bombs use fusion. Instead of splitting big atoms, it combines small atoms, like hydrogen to release a much bigger nuclear punch — hundreds of times more powerful.

With the development of an H-bomb, reclusive North Korea would be that much more of a threat.

A quick lesson in how it works

A hydrogen bomb is a complex bit of machinery. It’s basically two bombs in one.

While it gets its bang from fusion, it takes a lot of heat to get the process started — to get the atoms to smash together and start a nuclear chain reaction. That’s why they’re called thermonuclear weapons.

What better to do that with than another much smaller nuclear weapon. An atomic bomb works as the trigger to set off the hydrogen bomb. The two explosions are almost simultaneous.

The nuclear arsenals of the United States, Russia, United Kingdom, France and China are made up of these types of weapons.

India and Pakistan are believed to have atomic bombs.

A quick lesson in history

Atomic bombs have only been used twice in warfare — both times by the United States and both times on Japan.

The devastation led to Japan’s unconditional surrender and brought an end to the war.

Hydrogen bombs have never been used, although there have been times where the world seemed to be on the brink. The Cuban missile crisis in the 1960s is just one example.

Because of their devastating destructive potential, the nuclear powers are wary of using them. Nuclear treaties have rolled back nuclear warhead numbers in recent decades.

A quick look at the nuclear powers

Since dawn of the nuclear age, at least eight nations have conducted more than 2,000 nuclear test explosions.

The United States was the first one, detonating an atomic bomb in New Mexico on July 16, 1945. In the ensuing years, the U.S has been joined by the USSR/Russia, United Kingdom, France, China, India, Pakistan and North Korea. Israel is also believed to have nuclear weapons.

There are believed to be 10,000-15,000 nuclear warheads in the arsenals of the nuclear powers.

North Korea is the only nation to have conducted any nuclear tests since 1999, with tests in 2006, 2009, 2013 and this year. India and Pakistan both conducted nuclear tests in 1998.