Welcome to the Astronomical Society of South Australia

You don’t need a degree in Astrophysics to attend this presentation! Find out how the planets stay in orbit around the Sun. Discover the mysteries of General Relativity and the inner workings of the Universe.

The centre of our Galaxy harbours a massive black hole, Sgr A*, that is likely to be the oldest component of the Galaxy along with the invisible dark matter around it. How this amazing object came into existence and evolved over 13 billion years is intimately linked to the nature of the first stars, the chemical elements today and the evolution of dark matter and gas. Sgr A* is one of the fastest developing fields in astrophysics where discoveries are made every year. For example, the most energetic particles ever detected by IceCube in Antarctica, and by telescopes in Namibia and Argentina, are thought to have been created at the Galactic Centre. Our x-ray and infrared satellites pick up flaring activity near the black hole each day. The speaker discovered that Sgr A* triggered a huge explosion about 2 million years ago, when cave people walked the Earth; this was recently confirmed by NASA’s Fermi gamma-ray satellite. The new ESO Gravity instrument tracks the motion of the closest stars to Sgr A* and detects movement every single day! One star even reaches 32,000 km/s at closest approach, 12% of the speed of light. Other stars have escaped the Sgr A* region being ejected at speeds of 2000 km/s into the Galaxy. So what does the future hold and what can we learn from these remarkable observations? We will explore these topics and some crazy ideas.