What is it?
Time-based: This artwork displays and blinks the “Arecibo message,” a transmission sent towards star cluster Messier 13 from the then-new Arecibo radio telescope in 1974.
The Arecibo message is binary and can be decoded to a 23x73 pixel image. The message itself included encoded descriptions of the human body, DNA, our solar system, and base-10 number system, among other things. It is unclear how clearly it could be interpreted by beings unlike us.
It will reach its destination in 25,000 years. A response would take another 25,000 years at the speed of light.
The name refers to the first embryonic leaves that emerge from a seedling as it peeks out from the ground. Like a booster for a rocket, these leaves provide a burst of fuel, feeding the plant as it grows.