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Living with a Star: Understanding Solar Activity and its Terrestrial Effects - Peter Gallagher

03 November 2016 Research Case Studies from the Provost' Annual Review

The Sun, the source of light and heat for Earth, is a far from quiet star. From time to time it launches ejections of hot gas called solar storms, which can produce beautiful auroral displays on Earth and have more sinister effects on navigation and communications systems, satellite electronics, and power grids.

Provost Review case study

Due to an intense solar storm in November 2015, aircraft were not allowed to take off from airports in Sweden for over an hour, while in March 1989, a solar storm triggered a sequence of events that caused a nine-hour outage of the Hydro-Quebec power grid in Canada. A solar storm later that year caused a halt in all trading on Toronto’s stock market.

This is nothing new. In 1859, the largest solar storm on record occurred. The aurora that it produced was visible as far south as Italy in Europe and Jamaica in the Caribbean. Here in Ireland, the Irish Times of the day reported “the whole sky from the horizon to the zenith being irradiated with a rich purple tint [and] telegraph communications with all quarters were disturbed owing to some mysterious atmospheric influence”.

Trinity’s tradition in solar-terrestrial research
In Trinity, there is a long tradition of research in geomagnetism. Humphrey Lloyd, Professor of Natural and Experimental Philosophy, and Provost 1867–1881, built a magnetic observatory in the Provost’s Garden in the 1830s, and together with fellow Dubliner, Sir Edward Sabine, developed a global network of magnetic observatories. They became the first to confirm the link between solar activity and magnetic disturbances here on Earth. Later, the great Trinity physicist George Francis Fitzgerald (1851–1901) used a magnetometer located near the transatlantic telegraph cable in Valentia, Co. Kerry to show that variations in the Earth’s magnetic field could cause current surges in the telegraph cable – early proof of the damaging effects of solar storms on communications links.

The Rosse Solar-Terrestrial Observatory
To investigate these enigmatic Sun- Terrestrial connections, I have established a large and active research group in the School of Physics to understand the causes and consequences of solar storms, using data from European Space Agency (ESA) and NASA satellites. In addition, I have developed Trinity’s Rosse Observatory at Birr Castle, Co. Offaly to continuously monitor bursts of radiation from the Sun and their effects on Earth’s ionosphere and magnetic field. The data processing techniques my team is developing are used to characterize the ever-changing magnetic field of sunspots and track the dynamics of solar storms as they are launched, while their forecasting techniques are used to predict when solar storms will occur and when they might impact the Earth. 2016 is a particularly exciting year for the group as we begin building a large radio telescope called the Low Frequency Array (LOFAR) at Birr. This project, supported by Dermot Desmond, Denis O’Brien, Joe Hogan and Science Foundation Ireland, will connect Ireland to the largest network of radio telescope in the world and enable my team to study solar activity with better detail than ever before.

Space exploration
The Solar Physics Group also works closely with ESA and NASA teams exploring solar activity using their fleets of spacecraft. I am a Co-Investigator for the Solar Telescope Imaging X-rays (STIX) instrument which will be launched on ESA’s Solar Orbiter spacecraft in 2018. This ambitious mission will fly inside the orbit of Mercury giving solar physicists a closer view of the enigmatic Sun than ever before, keeping Trinity scientists at the frontiers of space exploration and solar-terrestrial physics.

04 May 2016

Mercury Transit in Trinity on 9th May 2016

Mercury transiting the Sun as seen from Earth in 2006. Mercury is the smallest planet in our Solar System, with a diameter of 4,879 km, while the Sun is an enormous 1.4 million km across — about 109 times the diameter of the Earth (12,742 km) Credit: ESA/NASA/SOHO

On Monday May 9th 2016 a rare transit of Mercury  across the face of the Sun takes place, and will be visible for us here in Ireland. During the transit, Mercury, the smallest planet in our Solar System, and also the planet closest to our Sun will pass directly between the Earth and the Sun. This gives us the opportunity to see the tiny dark dot that is Mercury transit across the bright surface of our closest star. There are only about 13 Mercury transits that are visible from Earth every century. The next ones are in 2019 and then 2032  - and much longer for us in Ireland.

The School of Physics will celebrate this rare event, and will be setting up two telescopes in Trinity's Front Square on Monday, May 9th from 12:00 noon. Additionally, a plasma TV displaying real-time observation of the transit will be shown from NASAs spacecraft called Solar Dynamics Observatory. This will let us view the transit even if it’s cloudy or raining.  Mercury will appear as a black dot about 1/150th of the Suns diameter, meaning it’ll be too small to see without magnification. The telescopes, with special solar filters, will let members of the public see what the Sun looks like and to see a planet moving through space across the vast face of our Sun. There will be plenty of expert astrophysicists from Trinity's Astrophysics Research Group on hand to talk to the members of the public about this exciting event, and to help all view the transit safely. 

Click here to find out more.


01 April 2016

There's Life On Earth But Not On Mars - Here’s One Reason Why

In March, a joint Euro-Russian mission to Mars was launched in a bid to investigate whether there is any sign of life on the red planet. The inhospitably cold, desert landscapes of Mars are a result of the atmosphere having been eroded over time, which was caused by the lack of a protective magnetic field.

Now a new study involving researchers from Trinity College Dublin, in collaboration with the Harvard-Smithsonian Center for Astrophysics (CfA), shows how such a protective magnetic field was critical for life on early earth.

Astrophysicists are all the time looking to understand how life could develop on other planets and, in particular, on our own Earth. This research initially focused on finding a star that was similar to the sun – a younger, solar twin.

Kappa Ceti is such a ‘twin’, and by studying it the teams involved gleaned insights into the early history of our solar system. In particular, that this ‘twin’ of our own sun emitted violent winds.

An artist’s illustration of the young sun-like star Kappa Ceti, blotched with large starspots, a sign of its high level of magnetic activity. Credit: M Weiss (CfA)

To be habitable, a planet needs warmth, water and it needs to be sheltered from a young, violent sun. A fierce stellar wind emitted by such a young sun would erode the atmosphere of any planet if there was no magnetic field in place.

What this study proves is that earth, unlike Mars for example, had a strong magnetic field, which provided sufficient protection for life to be sustained on this planet in the early years.

Speaking on the research, Aline Vidotto from Trinity’s School of Physics, commented: “We found that Kappa Ceti, a proxy of the young sun, should host a wind that is about 50 times stronger than the present day solar wind. This would have led to a larger interaction via space weather disturbances between the wind of the young sun and the young Earth."

These findings are published today in The Astrophysical Journal Letters. Link to journal: http://arxiv.org/pdf/1603.03937v1.pdf


15 Jul 2015

Invited Seminar by Dr. Viktor Fedun

The School of Physics will host an invited guest speaker Dr. Viktor Fedun of the University of Sheffield who will provide a 45 min seminar on advanced numerical simulations of the atmosphere of the Sun. This event is sponsored by the Dublin Graduate Physics Program (DGPP) which is funded through the HEA.

The Suns outer atmosphere is riddled with complex magnetic fields and explosive plasma processes, which evolve across spatial scales comparable with the size of the Earth. The theory that describes this extreme environment is Magneto-HydroDynamics (MHD) and solving the governing equations in 3D makes this a computationally intensive challenge. Dr. Feduns research is primarily concerned with the mathematical modeling of the physics of solar and space-based plasmas, Sun-solar wind and solar-terrestrial systems. The study of processes occurring in such systems is crucially important for understanding the heating of the outer atmosphere of the Sun, predicting space weather and understanding the dynamics of laboratory and technological plasmas.

This seminar will be of interest to physicists (in particular astrophysicists, mathematical physicists), computer scientists, numericists and those working within the experimental plasma research who may be interested in numerical modeling of plasma confined to magnetic fields, across a broad range of scales.

For further details and updates on the forthcoming seminar, please contact Dr. Eamon Scullion at scullie@tcd.ie.

A model of the surface of the Sun. Dr. Viktor Fedun, Lecturer in the University of Sheffield, UK

Event Details
Speaker: Dr. Viktor Fedun, Lecturer in the University of Sheffield, UK
Title: 3D numerical modeling of MHD wave propagation in realistic solar magnetic configurations
Date: Friday, 17 July
Time: 11:30 - 12:30
Venue: Schrodinger Lecture Theatre, Fitzgerald Building


23 Mar 2015

Data analysis begins for the 20 March Eclipse

With the day of last Friday's eclipse already a great success (despite unfortunate weather) for amateur eclipse watchers in Trinity's Front Square, scientific analysis has now begun on the data gathered. Shown above, light levels and temperature showed a clear trough centred around the maximum of the eclipse event at 9:30am.

Photos and total light and temperature measurements for the solar eclipse as seen from Dublin. Credit: Prof. Brian Espey


20 Mar 2015

TCD Astrophysics Group Help Visitors Catch a Glimpse of the Eclipse

TCD Astrophysics group aligning telescopes for the final moments of the eclipse.

The morning of 20th March 2015 was marked by a near-total solar eclipse visible from Dublin. These events occur whenever the moon passes directly between the Earth and the Sun, casting a shadow on the Earth which is hundreds of kilometres wide. While total eclipses take place somewhere on the planet every 18 months on average, being in the right place at the right time, with clear skies, can be very difficult.

The Front Square of Trinity College was packed with visitors eager to observe the event, despite forecasts of cloudy skies. Brief glimpses during near-totality at 9:30 caused an uproar among the crowds, and those who stayed until the end were treated to a completey clear view of the final stages of the eclipse, which was also caught with the WHS Monck Observatory located on top of the Fitzgerald building.

Final stage of the eclipse, imaged by the WHS Monck Observatory at the School of Physics


16 Jan 2015

Comet Lovejoy Visible to the Naked Eye This Month

The new year begins with excitement for astromoners as a rare comet makes it's first appearance without the need for large telescopes. Comet Lovejoy is a relatively bright comet in the evening sky at the moment and easily visible with binoculars. With an orbital period of 11000 years, this comet wont be visible again for a long time.

A number of useful charts showing the position of the comet on the sky, as well as its position in the solar system are available here. Comet chasers can find further information on ideal observing nights here.

Comet Lovejoy, photographed on 10 January 2015.