About 20 million years agoin a galaxy not so far away, a large star exploded and launched into space elements that are the building blocks of life.

A year ago, by chance, as the emitted light reached Earth, a team of scientists from Israel observed and for the first time collected data from the early stages of such an explosion called a supernova.

The picture they put together offers a detailed look at the origin of elements critical to our existence, such as the calcium in our teeth or the iron in our blood.

“In fact, we see the cosmic furnace where the heavy chemical elements are formed, the moment they are formed. We observe it as it happens. It really is the only opportunity,” commented Avisai Gal-Yam, an astrophysicist at the Weizmann Institute of Science.

The findings, published today in the scientific journal Nature, show that the giant star, located in the neighboring galaxy Messier 101 (also known as the “Spiny Wheel”), likely left behind a black hole after its explosion.

An amateur astronomer who happened to be watching this galaxy tipped off the researchers that something was up. They immediately turned their telescopes on the star and began recording the early stages of the explosion. The team, which included doctoral student and lead study author Erez Zimmerman, contacted NASA, which changed its schedule and pointed the Hubble Space Telescope at the supernova. This is how the ultraviolet light of the explosion was observed, which is blocked by the atmosphere and does not reach the Earth.

Along with the chemical elements ejected into space, such as carbon, nitrogen and oxygen, the ultraviolet data showed a discrepancy between the star’s initial mass and the mass ejected into space during the explosion. “We suspect that after the explosion a black hole was left behind, a new black hole that wasn’t there before. It’s the remains of the explosion. A portion of the star’s mass collapsed gravitationally and created a new black holeGal-Yam said.

Black holes are bodies with enormous density and gravitational forces such that nothing, not even light, can escape from them.

After creating a kind of “footprint” of a supernova from start to finish, Gal-Yam said scientists may be able to spot impending star explosions elsewhere.

“Maybe in a few years we will be able to say, not about all the stars but about some of them, that we suspect that such and such a star is going to explode. This will be great and we will know how to be prepared“, he added.