The Space Telescope NuSTAR has mapped the supernova explosion of Cassiopeia A. This is the first time that its radioactivity has been recorded and may reveal how stars explode.

Cassiopeia A was a star eight times bigger than our sun that exploded 11,000 years ago. However, due to its distance from our planet, we only discovered its existence and death 350 years ago, when the explosion's light arrived Earth.

When it exploded, it released radioactive materials that serve as a guide for the scientists today to know what might have happened to Cassiopeia A.

NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), which was launched in June 2012, was the first to map the radioactive materials released from the star's explosion. With the use of its two telescopes that focus high energy X-ray light, NuSTAR was able to monitor and show scientists the location and distribution of the radioactive material titanium-44.

Though the supernova explosion happened thousands of years ago, there is still plenty of titanium-44 to be monitored.

Brian Grefenstette, lead author and research scientist at the California Institute of Technology, said to CNN, "Until we had NuSTAR, we couldn't see down to the core of the explosion."

After examining data captured by the space telescope, the scientists speculated that the whole explosion started from Cassiopeia A's center. As powerful pressure builds up from its core, tiny particles called Neutrinos are produced. Neutrinos heat up the gas in the core, thus, leading to the star's explosion.

Grefenstette compared the powerful pressure with the hot bubbles formed at the bottom of the kettle when boiling water. Like those bubbles that try to rise through the cold material above, when the pressure goes up and get released, the whole thing begins to slosh around -- "it's like blowing the top off a pressure cooker, and the shock wave rips apart the star."

The scientists have no solid model on how the supernova explosion happens yet. Even so, they will continue working hard to know more, because, after all, our planet was believed to come from a supernova explosion five billion years ago.

This study was published in the Feb. 20 issue of the journal Nature.