Key chemical found at the edge of the Milky Way galaxy suggests alien life is common thanks to e.g. Galactic Fountains

Amazing stuff! We are not alone!

"Phosphorus – a key ingredient for life as we know it – was thought to be relatively rare in space. But now, astronomers have detected a surprising amount of the stuff on the fringes of the galaxy, suggesting life may be more common in the cosmos. ...
Life on Earth requires six critical elements: nitrogen, carbon, hydrogen, oxygen, phosphorus and sulfur (NCHOPS). Most of those are relatively easy to come by, as they’re blown into space as common low-mass stars reach the end of their lives. Phosphorus, meanwhile, is much rarer, and as such is generally considered the limiting factor for life in the universe. ...

The team used the radio telescopes at the Arizona Radio Observatory and IRAM in Spain to observe a molecular cloud named WB89-621. And sure enough, they detected the telltale signs of phosphorus monoxide and phosphorus nitride.

This cloud is located about 74,000 light-years away from the center of the Milky Way, which is almost twice as far out as phosphorus had previously been found. ...
Other teams have found evidence of phosphorus-rich stars, which could be contributing too. ..."

"... Their observations detected the telltale signatures of phosphorus – specifically phosphorus monoxide and phosphorus nitride – in a molecular cloud named WB89-621. Located nearly 74,000 light-years from the center of the Milky Way, the discovery extends the presence of phosphorus almost twice as far out as where it was known to exist. ..."

From the abstract:

"Despite its importance in planet formation and biology, phosphorus has been identified only in the inner 12 kpc of the Galaxy. The study of this element has been hindered in part by unfavourable atomic transitions. Phosphorus is thought to be created by neutron capture on 29Si and 30Si in massive stars, and released into the interstellar medium by Type II supernova explosions. However, models of galactic chemical evolution must arbitrarily increase the supernovae production to match observed abundances. Here we present the detection of gas-phase phosphorus in the Outer Galaxy through millimetre spectra of PO and PN. Rotational lines of these molecules were observed in the dense cloud WB89-621, located 22.6 kpc from the Galactic Centre. The abundances of PO and PN in WB89-621 are comparable to values near the Solar System. Supernovae are not present in the Outer Galaxy, suggesting another source of phosphorus, such as ‘Galactic Fountains’, where supernova material is redistributed through the halo and circumgalactic medium. However, fountain-enriched clouds are not found at such large distances. Any extragalactic source, such as the Magellanic Clouds, is unlikely to be metal rich. Phosphorus instead may be produced by neutron-capture processes in lower mass asymptotic giant branch stars which are present in the Outer Galaxy. Asymptotic giant branch stars also produce carbon, flattening the extrapolated metallicity gradient and accounting for the high abundances of C-containing molecules in WB89-621."

Key chemical found at the edge of galaxy suggests alien life is common

The case of the missing phosphorus: Astronomers find life ingredient at galaxy's edges The discovery of phosphorus in a molecular cloud at the edge of the Milky Way galaxy challenges current views of how the element originates and extends the galactic habitable zone.

Phosphorus-bearing molecules PO and PN at the edge of the Galaxy (open access)

Fig. 3: Abundances of PN and PO, as well as atomic phosphorus, as a function of distance from the Galactic Centre.