Imagine you were the first human to witness a lightning strike. It must have been terrifying. If it struck near you, there would have been an ear-splitting crack and a blinding, brilliant flash. Maybe even fire. You’d cautiously raise your head and know it came from the heavens but not why or how. Thousands of generations later, we still don’t really know the answers to those questions. But we have gotten good at enticing Zeus to smite us.
The International Center for Lightning Research and Testing (ICLRT) sits on 100 acres of airspace-controlled land at Camp Blanding Florida Army National Guard Base, 45 kilometers northeast of Gainesville, Florida. It is the outdoor test facility for the University of Florida’s ECE Lightning Research Laboratory. Here they fire rockets into thunderstorms.
Funded by agencies like the National Science Foundation, NASA, and DARPA, the ICLRT fires meter-long rockets into stormy skies that spool out hundreds of meters of Kevlar-reinforced copper wire behind them. In the 30 or so strikes that the lab induces during each Florida summer, triggers usually occur when the rockets reach the height of the Empire State Building. Then the sparks fly.
We know much more about how lightning forms than the first human to witness a strike, but as much as you would think. Lightning is what happens when nature is compelled to neutralize charges. We think that ice and dust particles bump around in the upper parts of the clouds above, creating a strong charge opposite that of the charge in the lower portion of the cloud. When the imbalance is large enough, the charge at the bottom of the cloud and the now opposite charge in the soil below send out staggered and snaking “leaders” that slither towards each other and connect for a massive electrical discharge. That’s the flash of light that brings the thunder.
In nature we have to wait for the circuit to be completed. The ICLRT gives nature a helping hand by immediately allowing any charge imbalances to race down the copper wire. The result is heat, light, and vaporized copper.
These brilliant photos show the energy held in relatively small lightning strikes. The green coloration is the obliteration of the copper wire. The multiple lines of light are the multiple pulses of the lightning strike. And the beautiful separation between the lines is from the push of wind as cameras record the nearly instantaneous event.
What do we learn from completing nature’s circuits? The ICLRT is hoping to answer the other question: Why does lightning start? Charge imbalances racing to meet each other make sense, but the electrical fields produced by the charge imbalances in clouds don’t seem to be strong enough to close the gap, like a sparkplug in your car does. But we know they do. We are missing something.
One prevailing theory is that what gets lightning going really is the heavens. Some experts think that cosmic rays – streams of high-energy particles blasting in from exploded stars across the universe – can strip electrons from atoms inside clouds and provide the conductive path necessary for lightning to start.
Until we have enough evidence to fully answer the how and the why of lightning, a small team of scientists will keep launching rockets into storms, trying to see lightning in whole new light.
Kyle Hill is the Science Editor at Nerdist Industries. Follow on Twitter @Sci_phile.
IMAGES: Dustin Hill; International Center for Lightning Research and Testing; Doug Jordan and Martin Uman