When we look up at the sky to view Orion the hunter, we're looking not just at a constellation but a place where stars are born. Within the constellation is the Orion Molecular Cloud 1. The European Southern Observatory explains how this works:
Stars are born when a cloud of gas hundreds of times more massive than our Sun begins to collapse under its own gravity. In the densest regions, protostars ignite and begin to drift about randomly. Over time, some stars begin to fall toward a common centre of gravity, which is usually dominated by a particularly large protostar — and if the stars have a close encounter before they can escape their stellar nursery, violent interactions can occur.
Just such a violent interaction occurred around 500 years ago when two protostars crashed into each other and caused an eruption. That eruption created a cloud that looks like a massive fireworks display, and is pictured here in impressive detail, thanks to the high resolution.
The tool that has brought us such an incredible view is ALMA, the Atacama Large Millimeter/submillimeter Array, which is considered the most powerful telescope for observing our universe's molecular gas and dust of which stars are made. When astronomers turn to ALMA, they're looking at what forms our universe and the history of it.
The ESO notes that this imagery of the recent collision within Orion will help astronomers understand how such an impact of stars and the resulting explosion might affect star formation in other places within our galaxy.