Hydrogen can play a major role in a clean, renewable energy economy. It can be used to store electricity generated by solar panels and windmills. The problem is that hydrogen is a gas and that makes it a challenge to store it. That’s why for nearly 100 years, scientists have dreamed of turning this lightest of all the elements into a metal. Now, in a stunning act of modern-day alchemy, scientists at Harvard University have finally succeeded in creating a tiny amount of what is the rarest, and possibly most valuable, material on the planet. Metallic hydrogen could theoretically revolutionize technology, enabling the creation of super-fast computers, high-speed levitating trains, and ultra-efficient vehicles and dramatically improving almost anything involving electricity.