Supernovae are a relatively common sight for astronomers peering out into space, but scientists have never witnessed the initial explosion of a distant star – until now. According to a report from Engadget, researchers working with the Kepler space telescope have captured the flash of the initial shockwave caused by an exploding star.

When the red supergiant KSN 2011d began to explode, the Kepler telescope happened to be pointed in just the right direction. The burst lasted only 20 minutes, sending a flash nearly 1.2 billion light-years before it was detected by NASA scientists.

The event is incredibly unique – it allowed astronomers to confirm some of the theoretical models of how a Type II supernova actually goes down. A Type II supernova occurs when a star is 8 to 50 times larger than our own sun.

The team missed the shockwave from the supernova caused by the explosion of a smaller red supergiant, KSN 2011a. This suggested that the explosions behave in different ways depending on the size of the star.

The large star created a massive burst of energy that put on quite a show for researchers using the Kepler telescope. As the red supergiant burned through the remainder of its nuclear fuel, it began to collapse in on its core and release massive amounts of stored energy.

According to Peter Garnavic, an astrophysics professor from the University of Notre Dame, “To put their size in perspective, Earth’s orbit about our sun would fit comfortably within these colossal stars.”

Garnavic says that the event was extremely rare, and the research team was fortunate to capture it for the first time. “In order to see something that happens on timescales of minutes, like a shock breakout, you want to have a camera continuously monitoring the sky. You don’t know when a supernova is going to go off, and Kepler’s vigilance allowed us to be a witness as the explosion began.”

A NASA press release describing the study can be found here.