Washington, Oct 5 (IANS): Astrophysicists have detected 150 supernovas, a record-breaking number in the Subaru Deep Field -- a full moon sized patch of sky -- which includes 12 of the most ancient and distant ones.

Supernovas, stars in the process of exploding, open a window onto the earth's early history, besides being a major source of iron in our universe.

The most ancient explosions, so far enough away that their light is reaching us only now, can be difficult to spot, according to a Tel Aviv University (TAU) study.

The discovery sharpens our understanding of the nature of supernovas and their role in element formation, say study leaders Dan Maoz, Dovi Poznanski and Or Graur, astrophysicists at TAU and Raymond and Beverly Sackler School of Physics and Astronomy, the journal Monthly Notices of the Royal Astronomical Society reports.

The research team includes the University of Tokyo, Kyoto University, (Japan) University of California Berkeley and Lawrence Berkeley National Lab (US), according to a TAU statement.

Supernovas are nature's "element factories". During these explosions, elements are both formed and flung into interstellar space, where they serve as raw materials for new generations of stars and planets.

Closer home, Maoz says, "These elements are the atoms that form the ground we stand on, our bodies, and the iron in the blood that flows through our veins."

By tracking the frequency and types of supernova explosions back through cosmic time, astronomers can reconstruct the universe's history of element creation.

In order to observe the 150,000 galaxies of the Subaru Deep Field, the team used the Japanese Subaru Telescope in Hawaii, on the 14,000-foot summit of the extinct Mauna Kea volcano.

Over the course of observations, the team "caught" the supernovas in the act of exploding, identifying 150 supernovas in all.