Mystery solved! Bizarre Hubble double galaxy caused by 'ripple' in space - Space.com

Now, scientists think, the objects are actually one distant galaxy that appears as two thanks to a "ripple" in the fabric of space that is magnifying and distorting its image.

Related: The greatest Hubble Space Telescope of all time.

Gravitational lensing was somehow not just magnifying the galaxy but also copying it, creating two bright images, as well as a fainter third copy that can also be seen in the image.

In addition, the lensed galaxy happens to sit upon a sort of ripple in space that's caused by the gravity of densely packed dark matter, the mysterious stuff that makes up about 85% of the matter in the universe.

The extra images were produced when light from the distant galaxy passed through the foreground cluster along this ripple, researchers said.

The "ripple" could help astronomers better understand how dark matter is distributed throughout the universe, team members said.

For example, by comparing the lensed Hubble images to computer models, the researchers determined that the dark matter in question likely wasn’t clumpy, but rather smoothly spread out.

"It's great that we only need two mirror images in order to get the scale of how clumpy or not dark matter can be at these positions," study co-author Jenny Wagner, an astronomer at Heidelberg University in Germany, said in the same statement.