Astronomers believe they have spotted a round, unassuming 'dinosaur egg' in the Milky Way. They think that it's getting ready to hatch, and will burst forth a wonder of stars, reports the National Radio Astronomy Observatory.
The object in question is a small, dense ball of gas that is devoid of stars. It is tucked away in the Antennae galaxies; two swirling, merging galaxies. Astronomers, who spotted the ball of gas using the Atacama Large Millimeter/submillimeter Array (ALMA), think that it might be the early stage of a globular cluster. A globular cluster is a spherical mega-bundle of active, burning stars. It is hot and emits a frenzy of radiation. But astronomers have never seen the birth of one of these clusters.
However, they're hoping they will now that they've found this new ball of gas 50 million light-years away. Their new findings will be published in the next edition of the Astrophysical Journal.
The birth of a globular cluster is speculated to happen when a huge cloud of stellar gas and dust condenses, building pressure all the time. Eventually, the pressure is so high that gas starts to burn and stars begin to pop up everywhere in the cloud. If this ball of gas, which has been nicknamed 'Firecracker,' becomes a globular cluster, then this will be a valuable opportunity to study the early lifetime of globular cluster formation.
Firecracker: An incredibly dense and massive, yet apparently star-free, cloud. This may be the first example of a prenatal globular cluster ever identified. Credit: NASA, ALMA
"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 press release. "This remarkable object looks like it was plucked straight out of the very early universe. 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.”
Firecracker is fairly quiet at the moment; it has no significant thermal emissions. Stars and other active cosmic bodies are responsible for thermal emissions and radiation, which is how astronomers know there are no stars present yet. All eyes and telescopes will be on Firecracker when it does start to explode with life in order to find out the conditions of globular cluster formation.
"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.”
Animation of ALMA data that depicts dense cores of molecular gas in the Antennae galaxies. The yellow object at the center may be the first prenatal example of a globular cluster ever identified. Credit: K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ)