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A Cosmic ‘Dinosaur Egg’ Is Hatching Between Colliding Galaxies

For the first time ever, astronomers have discovered a globular star cluster in its prenatal phase.

For the first time ever, astronomers have discovered a globular star cluster in its embryonic form, as a massive condensing ball of dust and gas.

While scientists have observed countless globular clusters—which are spherical mega-bundles of stars—in their active star-forming stages, this marks the only time a team has ever found a cluster that appears to be on the brink of birthing its very first stars. The new research will be featured in the upcoming issue of The Astrophysical Journal.


"We may be witnessing one of the most ancient and extreme modes of star formation in the universe," said astronomer Kelsey Johnson, the lead author of the study, in a statement released today.

"This remarkable object looks like it was plucked straight out of the very early universe," she continued. "To discover something that has all the characteristics of a globular cluster, yet has not begun making stars, is like finding a dinosaur egg that's about to hatch."

The cluster doesn't have an official name yet, but Johnson and her team have apparently taken to calling it Firecracker. It's located 50 million light years away, in the thick of an ongoing collision between the galaxies NGC 4038 and NGC 4039. Together, they are known as the Antennae Galaxies because their violent merger has ejected two characteristic tendrils of stars, dust, and gas that resembles insect antennae.

The Antennae galaxies with extensive clouds of molecular gas (center right image) and the Firecracker cloud (bottom image). Image: NASA/ESA Hubble, B. Whitmore (STScI); K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ); B. Saxton (NRAO/AUI/NSF).

This galactic smash-up is sparking rapid star formation, but the effects haven't yet reached Firecracker. Using the sensitive Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, Johnson and her team were able to pinpoint the whereabouts of this fledgling star factory by picking up its carbon monoxide levels. They were also able to determine that it has enough material to make about 50 million Suns, and that we're just in time to watch the show go down.

"Until now, clouds with this potential have only been seen as teenagers, after star formation had begun," said Johnson. "That meant that the nursery had already been disturbed. To understand how a globular cluster forms, you need to see its true beginnings."