DIAS Dunsink Observatory held two Public Open Nights in March with fascinating talks about the Observatory’s history, about the biggest stars in the universe, and about Space Weather.  These were the last in the 2018/2019 series of regular open nights, and we are looking forward to exciting development for next season – keep an eye on this blog for developments!

On March 20^th, DIAS PhD student Sam Green first gave a talk about the fascinating history of Dunsink Observatory from its origins to the present day. Topics included Sir William Rowan Hamilton who lived and worked here, timekeeping at the Observatory and Dublin Time, and research during the 20^th Century.

Jonathan Mackey then talk about “Massive Stars”, and how researchers use theory, computer models and observations to learn about the evolution of stars. Some stars explode and others collapse to black holes or fade away, and all stars change as they evolve, but much of this evolution is uncertain. Betelgeuse is one of the biggest stars we know of, and it is moving through interstellar gas fast enough to form a bow shock from its stellar wind interacting with the surroundings. Jonathan showed computer simulations of this bow shock and discussed what we can learn by comparing these models with observations.

He also spoke about Supernova 1987A which was the brightest supernova for 400 years. The exploding star was a blue supergiant and, once the explosion had faded, astronomers found three rings of light that are still visible and have never been fully explained. Jonathan showed some computer models that could explain how the three rings formed.  In May 2020 there will be an international conference on Massive Stars in Ireland where these and other topics will be discussed and debated in great detail.

There was then time for questions about the Sun and stars, and our visitors went out to the South Dome to see the historic Grubb Telescope.

On March 27^th the evening was beautiful and clear, at least to begin with (see the photo above).  We began with a talk from Prof. Peter Gallagher about the history of Dunsink Observatory, including its origins and the first director, Henry Ussher, who estimated the time difference between Greenwich Mean Time and Dunsink Time. Peter described the quaternions that were invented by another Director of the Observatory, Sir William Rowan Hamilton, and then described the many projects that the DIAS Astrophysics and Astronomy section is involved with, such as LOFAR and JWST. He then answered some questions about black holes and the weather on Pluto.

Following this, Dr. Sophie Murray gave a captivating talk on Space Weather, which is about how events in space can affect the Earth and its atmosphere, all the way down to the Troposphere. The Sun is the main driver of space weather through the solar wind and flares. Sunspots on the Sun’s surface can become unstable and release huge amounts of energy and hot gas into space in extreme events called Solar Flares and Coronal Mass Ejections (CMEs).  These shine brightly in X-rays and gamma rays, and some of the radiation reaches Earth.

Occasionally the hot gas shot off from the Sun’s surface also hits the Earth’s atmosphere. Fortunately the Earth is shielded by a magnetic field that deflects particles to the poles, creating an Aurora when the particles hit the atmosphere.  Extreme space weather events can trigger a Geomagnetic storm: when the Earth’s magnetic field changes suddenly, causing power surges on Earth which lead to blackouts. Sophie described the research that is being done by the UK MET Office, NASA, ESA and LOFAR on space weather. She finished by showing the forecast of the day’s space weather and then answered some questions relating to the Sun, Mars and a cyclone on Jupiter.

At 20.40 there was a break in Sophie’s talk as everybody went outside  to observe the International Space Station (ISS) as it passed over Dunsink Observatory. Peter explained how the Sun reflects off the ISS and makes it visible to the human eye. Seeing the ISS pass overhead with six people on board was very exciting for everyone.

Thank you to everyone for joining us during our Public Open Nights. Keep an eye on our website and social media for upcoming events.

Reported by our volunteer blogger Qi Qi Kennedy of DCU.