A Galaxy Breathes Out: How a Wind Is Born from Stars express
Two galaxies collided, and from their center an invisible fountain erupts. The ALMA and VLT telescopes peered into the heart of the IRAS20100-4156 system — where two stellar islands are merging. There, work is in full swing: hundreds of new suns are being born, and their heat drives a stream of cold gas outward.
This stream is like a giant's exhale. It carries away nearly half of all the molecular gas — the very raw material from which new stars could have formed. The wind's speed is 170 kilometers per second. Each year, it ejects a mass equivalent to 700 suns. If this continues, the entire gas reservoir will be depleted in 16 million years — a blink of an eye by cosmic standards.
The most surprising thing: the stream doesn't slow down. Usually, a wind weakens as it travels away from its source. Here, at a distance of five thousand light-years, it's still moving at the same speed. Something continues to push it. Most likely, it's light from millions of hot stars: it presses on dust grains and gas like wind on a sail.
The stream emerges as two cones — above and below the galaxy's plane. It's like a jet from a hose when you pinch the opening. The cones' direction aligns with the galaxy's rotation axis — meaning the wind breaks through where resistance is lowest.
This 'exhale' is not just a pretty sight. It decides the galaxy's fate: the expelled gas will never become stars. Perhaps this is how 'dead' elliptical galaxies are born: those where new stars no longer ignite. By observing IRAS20100-4156, we see a galaxy extinguishing its own stellar fire.
The speed of this galactic wind is 170 km/s. That's 500 times faster than the fastest airplane and 15 times faster than a rocket at launch.
In Stanislaw Lem's novel 'Solaris', the planet's ocean also ejects streams of matter into space — though for entirely different reasons.