To the sci-fi minded, strange lights hovering above Earth can mean only one thing…And yet, when astronaut Matthew Dominick spotted eerie flashes of colour in the planet’s atmosphere, his mind didn’t jump to an alien invasion. Instead, the NASA pro – who is currently spending six months on board the International Space Station (ISS) – took pictures of the dazzling celestial light show, which he knew to be the product of a perfectly natural, but mysterious, phenomenon.
The dazzling blasts were what are known as “red sprites” – strange spectacles associated with powerful lightning events. They are an example of colourful bursts of energy called transient luminous events (TLEs), which appear above particularly eventful storms, usually in the upper atmosphere.
Red sprites tend to occur at altitudes of 50 to 90 kilometres (31 to 56 miles) and their striking colour is caused by nitrogen in the atmosphere interacting with an electric charge, such as those present in lightning storms. When nitrogen encounters the electric charge it blasts out a red glow in the form of plumes and tendrils.
Dominick posted his red sprite picture to Twitter on 20 June, explaining that he had captured it while shooting a timelapse of a lightning storm off the coast of South Africa two-and-a-half weeks earlier. “If there are any red sprite experts out there I would enjoy tips on how to capture more of these,” he added in his tweet. “Clearly, look for lightning storms, but I'm thinking the stronger the storm the better.”
Meanwhile, NASA itself is asking for help in the hunt for red sprites, even setting up a citizen-crowdsourced database – dubbed ‘Spritacular’ – to which members of the public are urged to send their own snaps of sprites or other space oddities.
Space physicist Dr Burcu Kosar, principal investigator for Spritacular, noted in a statement: “People capture wonderful images of sprites, but they're shared sporadically over the internet. Most of the scientific community is unaware of these captures.”
In a separate press release about the red sprites, NASA urged followers to participate in the project and become “spritacular citizen scientists”. The space agency said: “While space station crew hunt for TLEs from space, you can help right here on Earth: send your photographs of sprites and other TLEs to NASA’s citizen science project, Spritacular, to contribute to a crowdsourced database that professional scientists can use for research.”
