Hubble Space Telescope witnessed something extraordinary over the course of just two decades. The Stringray nebula went from bright in 1996 to faded in 2016, as if it had been left hanging on a cosmic drying line. Stingray, more formally known as Hen 3-1357, was hailed as the youngest known planetary nebula when it was first noticed. The nebula formed during the star's end of life when it ejected glowing gases that gave it a marine-animal-like shape.
Nasa says that changes like this have never been captured at this clarity before and it is a rare look at a rapidly fading shroud of gas around an aging star.
Astronomers are taking notice of what both agencies described as unprecedented changes. The nebula had been emitting lots of nitrogen (red), hydrogen (blue), and oxygen (green), which gave it its distinct shape and glow in the original image.
The culprit is likely the central star inside the nebula which experienced a rapid rise in heat followed by a cooling phase. It seems Hubble got lucky with taking the images when it captured a before and after view of the nebula's wild swing. At this rate, NASA estimates it may be barely detectable within just a few decades.
Hubble team member Martín Guerrero of the Instituto de Astrofísica de Andalucía in Spain says that this is very, very dramatic, and very weird. What we're witnessing is a nebula's evolution in real-time.