A PHOTO taken by an astronaut in space has revealed a splattering of perplexing green lights seen glowing over a huge area near Thailand.

Reid Wiseman, one of the crew members on the International Space Station, noticed weird illuminations that shone as bright as cities out to sea in the Gulf of Thailand so, mystified, he immediately posted his discovery to Twitter.

#Bangkok is the bright city. The green lights outside the city? No idea… pic.twitter.com/TDzyin3hK7 — Reid Wiseman (@astro_reid) August 18, 2014

So what are these lights that even have NASA men stumped? Being in the middle of the ocean, explanation of city pollution is ruled out (unless they’re secret underwater ones? Hmm…), so could it be blooms of bioluminescent algae, a trick of light or something far more eerie? Theories ran wild from nuclear waste to aliens but it eventually it came to a fishy conclusion.

Truth Behind Green Lights in NASA Footage A space station video of East Asia, released by NASA this week, showing the stark contrast in electrification between South and North Korea also highlights another phenomenon. Thai fishermen suspend green lights from boats to illuminate the sea and attract phytoplankton, causing squid to come closer to the surface, making them easier to catch.

It turns out those mysterious lights are actually from fishing boats that use hundreds of striking bright green LED lights to attract squid, which normally hang out deep down, to the surface and straight to their jiggling hooks. The idea is they follow the plankton they feed on, which are drawn to the bright light. Very smart.

With the greenery stretching over miles and miles the image shows just how many fishing boats are out there but, more remarkably, how powerful those lights are to be seen from space. If you’re wondering what this must look like at ground level the lights fill the night skies to create an emerald aurora like this: