Sprites and Elves

You may remember that opposite electrical charges attract. If a positive charge builds up, it seeks to connect to a negative charge, to reach equilibrium. This is what creates lightning. As explained in a prior episode, it’s generated by the static electricity of water vapor and ice molecules rubbing against each other. Billions and billions of molecules can produce a whopping charge. Positive and negative charges build within the cloud, but they’re separated by air, which is a poor conductor. But once the charges are large enough, they overcome that resistance and connect as lightning—within the cloud or to Earth. Sometimes, though, a powerful charge builds in the top of the cloud, and rather than striking down, it seeks equilibrium by going … up! The charge leaves the top of the cloud and explodes into the atmosphere in what’s called a Transient Luminous Event, or TLE. There are several types, called Sprites, Blue Jets and Elves. That’s ELVES—Expanding Light emission from Very Energetic Sources. They take the shapes of columns, glowing rings or giant ‘jellyfish.’ But they last just a fraction of a second. Eyewitnesses saw TLEs 300 years ago. But it wasn’t until the advent of super high-speed video that scientists could capture their remarkable images to study them. Another reminder that there are still many things to discover, right here on—or just above—Earth.