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Hubble Telescope Spots an Intergalactic String of Pearls

Image: Merging galaxy clusters
The Hubble Space Telescope captured a cosmic moment of two merging cluster galaxies connected by a bright blue string of young stars. NASA / ESA / RIT / Hubble Heritage

No jeweler on the planet can beat the string of pearls spotted by the Hubble Space Telescope: The merger of two elliptical galaxies has created a "necklace" of infant stars stretching for 100,000 light-years.

Everything about this picture is big: The stellar string would stretch from one end of our Milky Way galaxy to the other, between two galaxies that are both three times wider than our own. The galaxies are contained in a cluster known as SDSS J1531+3414, a formation that's so massive its gravitation field bends the images of background galaxies into bluish arcs.

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When the images were acquired, astronomers assumed the chain of stars was merely an illusion created by the galaxy cluster's gravitational lens. But follow-up observations using the Nordic Optical Telescope in the Canary Islands ruled out that hypothesis.

"We were surprised to find this stunning morphology, which must be very short-lived," Grant Tremblay of the European Southern Observatory said in a news release from the Space Telescope Science Institute. "We've long known that the 'beads on a string' phenomenon is seen in the arms of spiral galaxies and in tidal bridges between interacting galaxies. However, this particular supercluster arrangement has never been seen before in giant merging elliptical galaxies."

Tremblay compared the phenomenon to "two monsters playing tug-of-war with a necklace."

The latest findings are in a paper due for publication in The Astrophysical Journal Letters — and you can find out more from the Rochester Institute of Technology as well as the European Space Agency's Hubble site.