Something is troubling astronomers. While lithium was one of the few elements created in the Big Bang, for some reason it is 10 times more prevalent in young stars than older ones. And astronomers have no idea why.

But a crucial step towards answering this question has been made. For the first time, lithium has been found [link to press release when it goes on here] in material ejected from a nova – a smaller stellar explosion than a supernova – capping 25 years of research. Astronomers had theorized previously that novae might be responsible for feeding young stars with lithium, but this is the first direct evidence that this could be true.

The team, led by Luca Izzo from the University of Rome, used the FEROS instrument on the MPG/ESO 2.2-metre telescope at the La Silla Observatory, as well the PUCHEROS spectrograph on the ESO 0.5-metre telescope at the Observatory of the Pontificia Universidad Catolica de Chile in Santa Martina near Santiago, to make the discovery.

They studied Nova Centauri 2013 (V1369 Centauri), the explosion of which was visible to the naked eye from southern skies on Earth in December 2013, the brightest nova this century.

Less than a billionth the mass of the Sun’s worth of lithium was spotted coming from the nova at two million kilometers (1.2 million miles) per hour – a tiny amount, but with billions of novae expected in the history of the Milky Way alone, it all adds up. The team said the quantities were sufficient to solve the long-standing lithium problem.

"It is a very important step forward,” said co-author on the study Massimo Della Valle from INAF-Osservatorio Astronomico di Capodimonte, Naples, and ICRANet, Pescara, Italy in a statement. 

“If we imagine the history of the chemical evolution of the Milky Way as a big jigsaw, then lithium from novae was one of the most important and puzzling missing pieces. In addition, any model of the Big Bang can be questioned until the lithium conundrum is understood.”

And, perhaps, we now may be on the brink of finally understanding it.