Washington  - A group of scientists has discovered the galaxy's newest supernova - as exploding stars are known - providing clues to what happens when stars die.

The supernova is just 140 years old, a baby in galactic terms, and is "by far the youngest identified supernova in the galaxy and the only one we know at its stage," researcher David Green of Britain's University of Cambridge told reporters Wednesday.

In addition to providing clues about the death of stars, supernovae interest scientists because they release massive amounts of energy, gases and elements that form the building blocks of life and can also form new stars or black holes.

"We're all stardust and it seems reasonable for us to what to know what happens when the stars explode," said Robert Kirshner of Harvard University's Smithsonian Center for Astrophysics.

Prior to the discovery of the supernova known as G1.9, the youngest supernova in the Milky Way galaxy dated to 1680.

The explosions are extremely bright and can be viewed from great distances often on Earth, but this supernova was not observed at the time because of its location at the centre of the galaxy where light years of dust and gases obscured it from view.

Scientists determined its age by looking at the supernova remnant through NASA and the National Radio Astronomy Observatory X-ray and radio telescopes, and noting its rapid expansion over the past two decades, they determined its young age.

"You get a lot more (information) when you put the clues together," Kirshner said. "It's like one of those television shows where they investigate a death. This is a stellar death and the corpse is still warm."

The supernova is also the smallest such explosion and material from it is expanding at the fastest speed scientists have observed, Green said.

Researchers estimate there should be about two or three supernovae each century, but far fewer are observed in the Milky Way galaxy, making Wednesday's announcement a milestone for astronomers. They said the discovery could provide clues as to how often they occur. (dpa)