Scientists in Germany flipped the switch Wednesday on an experiment they hope will advance the quest for nuclear fusion, considered a clean and safe form of nuclear power.

Following nine years of construction and testing, researchers at the Max Planck Institute for Plasma Physics in Greifswald injected a tiny amount of hydrogen into a doughnut-shaped device—then zapped it with the equivalent of 6,000 microwave ovens.

The resulting super-hot gas, known as plasma, lasted just a fraction of a second before cooling down again, long enough for scientists to confidently declare the start of their experiment a success.

"Everything went well today," said Robert Wolf, a senior scientist involved with the project. "With a system as complex as this you have to make sure everything works perfectly and there's always a risk."

To read more, click here.