The Hubble Space Telescope of NASA has captured images of goblin-green objects known as ephemeral quasar ghosts.

Quasar is a very luminous and compact region that surrounds a supermassive black hole at the centre of a galaxy. The Hubble observed them within eight different, distant galaxies. These unusual looped structures orbit their host galaxies and glow in a bright and eerie goblin-green hue.

According to scientists, these glowing structures have looping, helical and braided shapes and they don't fit a single pattern.

Quasars are the most active of these galaxy cores, where infalling material is heated to a point where a brilliant searchlight shines into deep space. The beam is produced by a disk of glowing, superheated gas encircling the black hole.

Bill Keel of the University of Alabama at Tuscaloosa, who initiated the Hubble investigation of the distant objects, said, “However, the quasars are not bright enough now to account for what we're seeing; this is a record of something that happened in the past”.

In the images captured, a quasar beam has caused once-invisible filaments in deep space to glow through a process called photoionisation.

Oxygen, helium, nitrogen, sulphur and neon in the filaments absorb light from the quasar and slowly re-emit it over many thousands of years. Their emerald hue is caused by ionised oxygen, which glows green.

The first object of this type was found in 2007 by Dutch schoolteacher Hanny van Arkel (heic1102). She discovered the ghostly structure in the online Galaxy Zooproject, a project asking help from the public to classify more than a million galaxies catalogued in the Sloan Digital Sky Survey (SDSS).

In Galaxy Zoo project, about 200 volunteers examined over 16 000 galaxy images in the SDSS to identify the best candidates for clouds similar to Hanny's Voorwerp.

A team of researchers analyzed these and found a total of 20 galaxies that had gas ionized by quasars. Their results appeared in a paper in the Astronomical Journal.