Public Lecture Report

The Extraordinary Universe; looking at Gamma-rays from Space

By Dr. Mark Lang, Head of School of Physics, NUI Galway

Monday 11 July

Trinity College, Dublin

On Monday, July 11th, Dr Mark Lang treated a large crowd of astronomy enthusiasts to a riveting lecture titled “the Extraordinary Universe – Looking at Gamma Rays from Space”

Dr Lang is the Head of the School of Physics in NUI Galway, home to Ireland’s longest running university astronomy degree. His principal research is in the field of Very High Energy (VHE) Gamma Rays which can be used to see an invisible universe of ultra hot stars and black holes.

The talk started with the clarification that Astronomy dealing with visible light is only one part of the story. This type of stargazing he describes as the “Ordinary Universe”. It has been the main area of study for astronomers for the first 300 years of telescopes and indeed before that. In the 20th century came developments in radio telescopes and sensors that allowed the capture of electromagnetic radiation that is outside the visible spectrum. This is where astronomy becomes “Extraordinary”!

Ultra Violet light, x-rays and even Gamma Rays are all emitted by objects and relate directly with how hot they are. The hottest things in the universe emit a very special type of radiation known as Very High Energy Gamma Rays. A single photon of visible light carries a charge of just over 1 Electron Volt. The light detected by Dr Lang’s principal research too the VERITAS array in Arizona detects light in the range of 30,000,000,000,000 Electron Volts.

At these energies it is difficult to detect them directly from the ground and so the VERITAS array relies on detecting Optical Shockwaves in the sky (brief flashes of light) when a VHE Gamma Ray impacts the upper atmosphere. When enough of these flashes are detected, the four detectors can begin to build a picture of where the VHE Gamma Rays are emitted from.

The talk proceeded to outline some of Dr Lang’s current research including information on the Crab Nebula which has recently been in the news after a surge in brightness. Dr Lang also gave the audience a preview of some top secret unpublished research he has been working on that will be published in the Journal “Science” over the coming months!

Following the lecture and a quick Q&A session, the conversation continued over refreshments and food in the Lombard.

If you could not attend the lecture, order a copy of the DVD HERE.