NUI Galway's Centre of Astronomy will continue its series of public talks with the next lecture exploring the topic of Gamma Ray Bursts (GRBs). The free lecture will take place on Wednesday, 10 February, at 7.30pm in the McMunn Theatre, NUI Galway. The lecture, which will be delivered by NUI Galway's Dr Gregg Hallinan, will focus on the mysterious GRBs, which are flashes of gamma rays associated with extremely energetic explosions in distant galaxies. Although most GRBs take place in the far reaches of the universe, they still result in the detection of large amounts of energy on earth. It has been hypothesised that a close GRB, originating in our own Milky Way galaxy, could have previously caused a mass extinction on Earth. GRBs occur approximately once per day, when a bright flash of deadly gamma radiation is detected coming from a wholly random direction in the sky. Until recently GRBs were one of the biggest mysteries in astronomy. When initially detected in the late 1960s, the United States suspected that the USSR might be attempting to conduct secret nuclear tests on the far side of the moon. However, it was soon established that these bursts were coming from outer space, although it took three decades of active research to find out what actually caused these bright flashes in the sky. Speaking about the lecture, Dr Hallinan said: "We now know that most GRBs signal the biggest explosions in the universe since the Big Bang. These explosions are a million trillion times as bright as the Sun, and are caused when the very largest stars run out of fuel and are torn apart by their own gravity, resulting in the formation of a black hole. During the lecture I will explain the history of how GRBs were discovered and the quest to understand them, as well as their importance in astronomy and their potential threat to humanity". More details about this lecture series can be found on http://astro.nuigalway.ie/outreach.php. -Ends-