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28 January 2021 | Story Igno van Niekerk | Photo Supplied
Pictured from the left: Lucas Erasmus from the Department of Physics, Piet le Roux from the Astronomical Society of SA – Bloemfontein, Quinton Kaplan from the Department of Physics, Thinus van der Merwe from the Astronomical Society of SA – Bloemfontein. Front: Prof Matie Hoffman

In his book, The World is Flat, Thomas Friedman mentions how at first countries, then companies, and eventually communities went global. In true flat-world fashion, a combined team of the University of the Free State (UFS) and the Astronomical Society of South Africa – led by Prof Matie Hoffman, Associate Professor in the Department of Physics – participated in a once-in-a-lifetime event with their counterparts from the Ellinogermaniki Agogi School and the Skinakas Observatory in Greece.

On 21 December 2020, Earth was treated to the Jupiter-Saturn conjunction, when the two planets were only 0.1 degrees apart in the sky. Although conjunctions are regular phenomena, NASA mentions that the great conjunction of Jupiter and Saturn in 2020 was the closest since 1623 and the closest observable since 1226! A pinkie finger at arm’s length could cover both planets – although they were still millions of kilometres apart in space.

Planning started months ahead of the event, with the Ellinogermaniki Agogi Observatory in Greece and the Boyden Observatory in Bloemfontein chosen as the two selected vantage points. From both the Southern and Northern Hemisphere, the conjunction would be broadcast live on YouTube. As with any other technical project on an international scale, challenges arose. For example, in the Northern Hemisphere, it was already dark at 17:45 while the South African astronomers were still basking in sunlight until after 19:00. The conjunction would only be visible from South Africa after 19:30, almost two hours after it would be visible in Athens. The time was well used, with the event including a word of welcome by the Consul General of Greece in South Africa, Ioannis Chatzantonakis, presentations on Saturn and Jupiter, as well as a virtual tour of the Boyden Observatory, emphasising its connection with Greece through its first Director, Stefanos Paraskevopoulos. 

On Saturday, 19 December, the teams ‘gathered’ on opposite sides of planet Earth to do a dry run. One could sense the urgency and tension as both teams realised that they would have a huge captive audience on YouTube, and plans had to be made in case of connectivity challenges and if the weather did not allow the conjunction. As preparations progressed, Prof Hoffman was talking to his Greek counterparts and was simultaneously walking around with his laptop to share the landscape and activities via his webcam with colleagues in Greece. 

Monday 21 December 2020 – the weather prediction was correct. Clouds covered the Free State sky and scattered raindrops started to fall. Revert to Plan B. A recording made on Saturday evening was shared via the YouTube link, while a live feed of the conjunction from elsewhere in South Africa was arranged. From both sides of the world, information was shared about the history of the venues, as well as the marvel of what was happening in space. Fortunately, expert planetary photographer Clyde Foster was able to share a live feed just after 19:30 from the observatory at his home in Centurion, Gauteng. Those attending the event where visuals and speakers were together on one screen – yet thousands of kilometres apart – watching an event in outer space, will indeed agree with Thomas Friedman: the world is flat. The live-stream event of the conjunction was a catalyst that will result in continued collaboration between the UFS and colleagues in Greece in the field of astronomy. 

By the time of this writing, the livestream has reached more than 50 000 people.


News Archive

Two scientists part of team that discovers the source of the highest energy cosmic rays at the centre of the Milky Way
2016-03-22

Description: Giant molecular clouds  Tags: Giant molecular clouds

Artist's impression of the giant molecular clouds surrounding the Galactic Centre, bombarded by very high energy protons accelerated in the vicinity of the central black hole and subsequently shining in gamma rays.
Artist's impression: © Dr Mark A. Garlick/ H.E.S.S. Collaboration

Spotlight photo:
Dr Brian van Soelen and Prof Pieter Meintjes of the UFS Department of Physics.
Photo: Charl Devenish

H.E.S.S. (High Energy Stereoscopic System) scientists publically revealed their latest galactic discovery in the international science journal, Nature, on 16 March 2016. These scientists were able to pinpoint the most powerful source of cosmic radiation – which, up to now, remained a mystery.

Part of this team of scientists are Prof Pieter Meintjes and Dr Brian van Soelen, both in the University of the Free State (UFS) Department of Physics. Dr Van Soelen explains that they have discovered a proton PeVatron – a source that can accelerate protons up to energies of ~1 PeV (10^15 eV) – at the centre of the Milky Way. The supermassive black hole called Sagittarius A has been identified as the most plausible source of this unprecedented acceleration of protons.

The protons are accelerated to Very High Energy (VHE) gamma rays. The energy of these protons are 100 times larger than those achieved by the Large Hadron Collider at CERN (the European Organization for Nuclear Research).

According to Dr Van Soelen, the fact that this research has been published in Nature demonstrates the importance and pioneering nature of the research conducted by H.E.S.S. The H.E.S.S. observatory – operational in Namibia – is a collaboration between 42 scientific institutions in 12 countries.

In 2006, H.E.S.S. was awarded the Descartes Prize of the European Commission – the highest recognition for collaborative research – and in 2010 the prestigious Rossi Prize of the American Astronomical Society. The extent of the observatory’s significance places it among the ranks of the Hubble Space Telescope and the telescopes of the European Southern Observatory in Chile.

“The next generation VHE gamma-ray telescope,” Dr Van Soelen says, “will be the Cherenkov Telescope Array (CTA), which is currently in the design and development stage.” Both Dr Van Soelen and Prof Meintjes are part of this project as well.

H.E.S.S. has issued a complete statement about the paper published in Nature.

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