Hubble Delivers Beautiful Photo of a Glowing Cosmic Chandelier

The NASA/ESA Hubble Space Telescope is still going strong and delivering unbelievably beautiful deep-space images. The latest Hubble image shows globular cluster NGC 6723, sometimes called the Chandelier Cluster. This name is well-earned, as it is an extremely dense stellar cluster, each star looking a little light on a giant cosmic chandelier.

A global cluster like NGC 6723 is a collection of many stars, ranging from tens of thousands to millions, all tightly bound by gravity. In the case of NGC 6723, which is located 27,000 light-years from Earth in the constellation Sagittarius, the stars are particularly ancient. The stars in the Chandelier Cluster are among the oldest in the Milky Way galaxy. Some of these stars are more than 10 billion years old, others are nearly as old as the Universe itself.

“Astronomers think globular clusters are some of the first structures that formed in our galaxy, coalescing potentially billions of years before the thin disk of stars in which our Sun orbits,” NASA explains.

However, how globular clusters even formed in the first place remains uncertain, which is why space telescopes like Hubble and the James Webb Space Telescope investigate them so closely.

Astronomers used to believe that all the stars in a globular cluster formed at once, in a single, incredible moment of stellar birth. However, thanks to observations from telescopes like Hubble, scientists determined that global clusters like NGC 6723 contain stars of diverse ages, meaning that the history of globular clusters is much more complicated than initially hypothesized.

Hubble first peered at NGC 6723 as part of a large survey of globular clusters in the Milky Way. Hubble studied 65 different relatively nearby globular clusters, and this survey has proven “immensely scientifically valuable” and informed hundreds of published research papers. As is often the case with Hubble’s images, beautiful photos are also extremely useful for scientific research.

In the case of the Chandelier Cluster specifically, researchers determined, thanks to Hubble’s unique ultraviolet imaging capabilities, that NGC 6723 experienced two closely spaced periods of star formation. The second one occurred within 634 million years of the first.

“‘Closely-spaced’ is relatively,” NASA adds. “634 million years is a blink of an eye for a star cluster that is more than 10 billion years old!”

“Thanks to these findings, astronomers are on the path to understanding how and when globular clusters formed — and Hubble observations of celestial chandeliers like NGC 6723 are lighting the way,” NASA concludes.

Image credits: ESA/Hubble & NASA, A. Sarajedini, G. Piotto