One hundred billion stars whirl about each other and, collectively, around the Galaxy, yet rarely do they ever collide. This is because stars are much more likely to interact with each other the way people do in a square dance: namely, by approaching one’s partner, linking arms while skipping in a full circle ’dosey-doh,’ and then making a retreat.
One tries to avoid the full-on collision to preserve the health of one’s partners. Stars interact similarly to well-trained square dancers, by exchanging momentum with the partner star. The two stars approach, describe a circular ‘dosey-doh,’ and then move away. Having said that, every so often two stars find themselves on a path to a direct collision. This event is so unlikely, and so short-lived, that astronomers do not often get the opportunity to see it.
One of the best chances to look for such an unfortunate activity is in stellar nurseries called molecular clouds. This is because stars are born in groups and ‘incubate’ close to each other. It is only later than when they are fully established stars calmly converting hydrogen into helium that they drift away from their siblings to safer distances.
Astronomers have recently discovered the remnants of a this ultra-rare stellar collision in a molecular cloud in the direction of the constellation of Orion. The event produced a large explosion which sent debris flying in all direction at reckless speeds of greater than 330,000 miles per hour! With high spatial resolution data of the aftermath taken at the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, astronomers are able to map out this debris and study the consequences of this collision between two infant stars.
Based on the data, it is inferred that this explosion managed to inflict significant damage to the stellar nursery, and in the process shut down the route to make new stars at that particular location. But not worry, the Milky Way has a healthy birth rate of stars which is likely to continue for a good long while.