February 22, 2023 - In the centre of the Earth's inner core, there is another layer: the innermost core, which is a solid "metallic ball," asserted Croatian scientist Dr. Hrvoje Tkalcic and his associate Dr. Thanh-Son Pham from the Australian National University in a paper published in the journal Nature Communications (ANU) in Canberra.

As Jutarnji writes, in school, we were taught that the Earth's interior consists of four layers: crust, mantle, outer and inner core. The border between the Earth's crust and the mantle is called the Mohorovičić discontinuity or Moho layer because it was discovered by the Croatian scientist Andrija Mohorovicic (1857-1936), which is one of the most significant discoveries in seismology of the 20^th century. Now, however, Croatian scientist Hrvoje Tkalcic is changing the existing knowledge about the interior of the Earth.

Twenty years ago, scientists made the assumption about the existence of the innermost core, and using data collected from seismic waves caused by earthquakes, Tkalcic and Thanh-Son Pham proved it. They analysed data from around 200 earthquakes of magnitude 6.0 and above in the last ten years. For example, one of the earthquakes studied by scientists occurred in Alaska. The seismic waves generated by that earthquake "rebounded" somewhere in the South Atlantic before travelling back to Alaska.

"These are observations of waves that spread two, three, four, or five times along the Earth's diameter after large earthquakes. These waves are bounced multiple times through the Earth's interior, like a ping pong ball bouncing in the same direction, and pass through its very centre. We observed these multiple paths of waves through the centre of the Earth for the first time in the history of seismological observations", said Dr. Hrvoje Tkalcic, professor of seismology and mathematical geophysics and head of the Department of Geophysics at the Australian National University (ANU).

Updates in textbooks

Secondly, by measuring the time of the passage of seismic waves through the interior of the Earth's core, we confirmed that the inner core has two parts. The inner part is the central core, and the outer part is the shell that surrounds it. Both the central inner core and the shell surrounding it are alloys of iron and nickel in a solid aggregate state. However, what differentiates them is not their chemical composition but the direction in which the waves slow down through them. In jargon, this is called anisotropy. In other words, the central core and the outer shell that surrounds it are anisotropic, each in its way, either because of the different crystal structure of iron (the way the iron atoms are arranged in the crystal lattice) or because of the orientation of the crystal", explained Tkalcic. This Croatian scientist is one of the leading world experts in understanding the Earth's inner core, about which he published a book published by Cambridge University Press in 2017, the first of its kind in the world.

He pointed out that studying the deep interior of the Earth's inner core can tell more about the past and evolution of our planet.

"This inner core is like a time capsule of the Earth's evolutionary history – a fossilized record that serves as an insight into the events of our planet's past. This helps us understand the Earth's history, that is, the conditions that prevailed during the crystallisation of the Earth's inner core, in a similar way to how we study the age of trees and the climatic conditions that existed on Earth. I think that with this work, we have put a dot on the 'i' and confirmed the existence of the central core of the Earth. The time has come for the illustrations of the Earth's internal structure in textbooks to change", emphasised Hrvoje Tkalcic.

Who is Hrvoje Tkalčić?

He was born in 1970 in Bjelovar, went to high school in Vinkovci, and graduated in physics - majoring in geophysics at the Faculty of Science and Mathematics (PMF) in Zagreb. He received his doctorate on the subject interior of the Earth's core at the University of California, Berkeley. Then he was a postdoctoral fellow at the Scripps Institute in San Diego and the Lawrence Livermore National Laboratory, the largest nuclear laboratory in the USA.

He is the recipient of the Australian Research Achievement Excellence Award, the British Price Medal, and a member of the American Geophysical Union (AGU). Also, prof. Tkalcic is an excellent populariser of science: his book, "Earthquakes: Giants That Sometimes Wake Up," published last year by Ljevak, is very popular among readers.

Open access to the paper, as shared by the professor on Twitter. 

For more, make sure to check out our dedicated News section.

Dr David M. Smith has been once again confirmed as the Rudjer Boskovic Institute director for the second time following a recently held session at which this decision was made.

As Poslovni Dnevnik writes, at a session held on February the 18th, 2022, the Governing Board of the Rudjer Bosković Institute (RBI) elected Dr. sc. David Matthew Smith as the director for a term spanning four years, beginning during this one.

The Governing Board elected Dr. sc. Smith after considering the positive opinion of the Tender Committee and the Scientific Council, and appointed him as the Rudjer Boskovic Institute director for the term of office from 2022 to 2026.

This is otherwise Dr. sc. This is David M. Smith's second term as the Rudjer Boskovic Institute director. The previous four-year period during which he held this same position was marked by numerous global challenges, but also great results of this most famous Croatian institute and the conclusion of a historic contract for the capital infrastructure project Open Science-Infrastructure Platform for Innovative Applications in Economy and Society (O-ZIP).

In this continually challenging period, this institute has further strengthened its position as a leading Croatian institution in terms of contracting international and domestic projects, and has shown excellent progress in contracting development projects in cooperation with the business sector through structural funds.

"I would like to thank the Governing Board and the Scientific Council, and in particular all the employees of the Institute for their support in my work so far and, in particular, for their renewed trust for this, my second term. I'm hereby honoured and entrusted with a great responsibility in continuing to lead the Institute. Behind us is a very challenging period marked by earthquakes and a pandemic, but also great results of the RBI. Moreover, a quick review of the Nature Index, which measures production in leading international scientific journals, shows that the RBI is responsible for approximately half of Croatia's overall contribution.

About 300 competitive Croatian and international scientific projects are currently being implemented at the Rudjer Boskovic Institute and the European project portfolio has reached a value of 110 million euros. A historic contract has been signed for the capital structural project O-ZIP, which brings us an investment in RBI infrastructure worth 72 million euros, the number of publications has grown, and we've achieved significant results in the ''brain drain'' to the RBI by attracting foreign scientists and returnees, which makes me especially happy, as does the influx of doctoral and postdoctoral students at the RBI.

Flexibility and adaptation to these new working conditions will be our everyday life in the future. Stability, harmonisation and progress are the key points of my vision of the RBI, while the greatest strength of this institute is its employees,'' said Dr. sc. David M. Smith upon being appointed as the Rudjer Boskovic Institute director once again, adding that he hopes that the institute will continue to achieve these results in somewhat more stable conditions in the future.

For more, check out our lifestyle section.

January 23, 2022 - A tribute to one of the greatest minds of Croatian science, born on this day 165 years ago

In 2007, an initiative was launched in Zagreb to erect a monument to Andrija Mohorovičić, a world-renowned geophysicist and founder of modern seismology. It’s been a minute, but the Croatian Academy of Sciences and Arts has finally announced that the project will be implemented in the capital city this year to mark the 165th anniversary of the birth of the researcher (HINA).

As we're waiting for one of the greatest minds of Croatian science to get a tribute he deserves, let's look at his life and career before another 15 years go by. Who was this great man and what is his legacy? 

Mohorovičić was born in 1857 in the small Croatian town of Volosko (near Opatija) and finished secondary school in Rijeka. He was a talented pupil from an early age and spoke fluent Italian, French and English by the time he was 15; he'd go on to learn Latin, Ancient Greek, Czech and German later on.

Childhood home of A. Mohorovičić in Volosko

He studied mathematics and physics in Prague, then went on to teach high school in Zagreb, Osijek, and at the Royal Nautical School in Bakar (near Rijeka). This was a turning point in his scientific career, as that’s where he developed a strong interest in meteorology and established a weather station in Bakar as a result.

In the 1890s, he requested a transfer to Zagreb where he soon took over the reins of the Meteorological Observatory, all the while teaching courses on geophysics and astronomy at Zagreb University. What equipment he didn’t have, he designed and built on his own, such as a nephoscope, an instrument for observation of clouds he used to collect readings for his doctoral dissertation.

Mohorovičić was the first person to establish a public time service and also the first to publish weather forecasts in newspapers. He’s remembered as a meticulous researcher who unified the weather service in Croatia and set high standards for further development of meteorology.

Portrait of Mohorovičić in Opatija

And then, another turning point at the beginning of the 20th century. Even though he continued to consistently record meteorological observations, Mohorovičić shifted his interest to seismology and essentially started from scratch where his career was considered, as this particular field was not much developed in Croatia at the time.

It’s not really known what inspired the scientist to turn to a completely new field of research, but it’s believed it was the lively seismic activity around Zagreb that piqued his interest. Mohorovičić installed the first seismograph at the Meteorological observatory in Zagreb, effectively founding a seismological station in 1906.

He soon replaced the instrument with two more advanced seismographs, which he would use to record data during the Kupa Valley earthquake in 1909.

Those readings, together with others recorded all over Europe, led to his biggest scientific discovery: the Mohorovičić discontinuity, or Moho for short, the boundary between the Earth’s crust and the mantle. The same boundary on Mars and the Earth's Moon also bear his name. 

Having studied the effect of seismic activity on buildings, Mohorovičić was also a strong advocate of earthquake-resistant construction. He held a series of lectures at the Croatian Society of Engineers and Architects starting from 1909, in which he set out to explain ‘how the Earth trembles, and how these tremors affect buildings, and draw attention to some principles that both architects and building contractors should follow’.

Quite a straightforward concept today, but a groundbreaking approach in the early 20th century, especially given that he urged developers to ‘consider the earthquake hazard and spend more, in order to make buildings more resistant and safe’. Over 100 years later, we still haven’t learned our lesson.

Mohorovičić was truly a man ahead of his time, a visionary and a scientific pioneer in many ways. He was one of the few Croatian scientists of international renown to remain based in their homeland for their entire career; he taught at university level, published papers and remained a member of the Yugoslav Academy of Sciences and Arts until he retired in 1921.

Owing to his greatest discovery, a crater on the far side of the Moon bears his name, as well as an asteroid, a secondary school in Rijeka, and a training ship of the Croatian Navy.

This article is mainly based on an essay written by Davorka Herak and Marijan Herak of the Andrija Mohorovičić Geophysical Institute. 

January 5th, 2022 - On this day in 1896, the discovery of X-rays first made the news. The groundbreaking invention soon had its Croatian debut, and once you start looking into the story, it quickly becomes apparent what a lively place Rijeka was at the time. Join us as we go down a historical rabbit hole, featuring a naval academy, a few visionaries - and Captain von Trapp

On January 5th, 1896 a groundbreaking scientific discovery was presented to the public. The Austrian newspaper Wiener Presse first reported that Wilhelm Röntgen discovered a new type of radiation - X rays.

While the German scientist himself named the radiation ‘X’, to this day it’s referred to as Röntgen rays in many European languages, including Croatian (getting an X-ray translates to taking a Röntgen).

A lesser known fact is that X-rays made their Croatian debut shortly after the first international reports of Röntgen’s discovery.

In the late 19th century, the Royal Naval Academy in Fiume (Rijeka) used to be one of the leading educational and scientific institutions in the Austro-Hungarian empire. Its prestigious reputation attracted a lot of talent from all over the empire, including an Austrian physicist named Peter Salcher.

Peter Salcher (1890)

Salcher joined the academy as a physics and mechanics professor, and soon became head of the meteorological station. He was a Renaissance man of sorts, a curious mind interested in science at large, as well as scientific photography and photojournalism.

It’s no wonder that the news of Röntgen’s discovery piqued his interest. On February 21st 1896, Salcher held a public lecture in Rijeka at which he demonstrated the usage of X-rays. Naturally, the local high society was eager to attend the thrilling presentation, among them baroness Josephina Mollinary-Vranyczany.

The baroness bravely volunteered as a test subject for the curious invention, and so Salcher took an X-ray of her hands before the excited audience, the first X-ray image created in Croatia. This one:

X-ray image of baroness Josephina Mollinary-Vranyczany's hands (1896)

Shortly thereafter, the city hospital in Rijeka adopted the invention and began using an X-ray device.

This is not the only thing Salcher’s remembered for, as he was the man behind another groundbreaking scientific experiment that took place in Rijeka. A decade before X-rays were invented, Salcher made history by recording the flight of a bullet shot from a firearm using a special high-speed photography technique.

He devised the experiment after he’d been approached by Ernst Mach, a physicist who was having trouble proving his shockwave theory in practice. Salcher got to work with the help of his associate Sándor Riegler, resulting in 80 shots of supersonic flying bullets. It was the first such achievement in history, and the images can be seen at the permanent exhibit at the Rijeka City Museum.

An image of a flying bullet taken by Peter Salcher (1886)

At this point, we very well might be playing six degrees of separation. Many prominent figures were part of the scientific community in Rijeka back in the day, including a particular student of professor Salcher who would later gain international fame.

It was Georg von Trapp - yes, that von Trapp, the head of the family whose story inspired The Sound of Music. A member of a noble family of Austrian origin, Georg Ludwig von Trapp was born in Zadar and entered the Naval Academy in Rijeka at the age of fourteen, which led to an illustrious military career as a naval officer.

Georg Ludwig Ritter von Trapp

Von Trapp married Agathe Whitehead, granddaughter of Robert Whitehead, the inventor of the modern torpedo and founder of the world’s first torpedo factory. The couple met at the launch of a newly built U-boat in Rijeka where Agathe had the honour of christening the vessel; Georg reportedly fell head over heels for her at the celebratory ball on the same evening. They were married after a two-year courtship - learn more about their love story on the pages of the Georg & Agathe Foundation.

Georg von Trapp and Agathe Whitehead (circa 1909)

Agathe died of scarlet fever in 1922, and Georg moved into a villa near Salzburg with their seven children. You surely know how the rest of this story goes - he hired Maria Augusta Kutschera as the kids’ tutor, they got married a year later and had three more children together. Since everyone in the family was musically gifted, they soon started performing as a vocal ensemble around the world, eventually moving to the United States.

The Trapp Family ensemble at a 1941 performance

Maria Augusta wrote a memoir about the musical journey of the von Trapp family. It served as inspiration for several German films, the 1959 Broadway musical, and the 1965 film The Sound of Music.

So many good stories, all connected to each other - it seems Rijeka really was the place to be at the turn of the century, wasn't it? 

ZAGREB, April 24, 2020 - An interdisciplinary team of Croatian scientists has determined the genetic sequence of the COVID-19 virus genome, which will make it possible to determine the source of the infection in Croatia and track it as well as contribute to global efforts to curb the pandemic.

The Zagreb-based Ruđer Bošković Institute (IRB) said in a statement that this was a joint success of its researchers and those working at the Rijeka School of Medicine and the Teaching Institute for Public Health.

The success confirms that Croatia has both the technical and human resources that place it along other countries contributing to the understanding of the SARS-CoV-2 virus.

The first detailed analysis of the virus genome was done at the IRB Laboratory for Advanced Genomics, led by Oliver Vugrek.

Participating in the project were also Igor Jurak of the Rijeka University Department for Biotechnology and Tomislav Rukavina and Neven Sučić of the Rijeka School of Medicine and Teaching Institute for Public Health.

Their results have helped develop an own protocol for the analysis of the COVID-19 disease, which could be applied broadly in the analysis of other viruses too, the IRB said.

More coronavirus news can be found in the Lifestyle section.

ZAGREB, April 21, 2020 - Karlovac County authorities on Tuesday presented the Nikola Tesla Experience Centre, which is being built by the Karlovac High School, on the occasion of World Creativity and Innovation Day.

Damir Pintarić, director of the AB construction company in charge of the project, said that the centre has a gross area of 750 square metres.

The contractor is currently building partition walls and will soon start installation works and work on the roof and facade.

Pintarić said that in the current situation caused by the coronavirus pandemic, the company had to reduce the number of workers and introduce anti-epidemic measures.

Deputy county head Martina Furdek Hajdin expressed hope that the new centre would be a place where young people would find the inspiration to be innovative and creative, the more so as Tesla attended the Karlovac High School.

The project is worth HRK 15 million and its first stage will be completed by September.

Furdek Hajdin said that money for the completion of the project was expected to come from the EU's next financial perspective.

The county has secured HRK 9.6 million for the project, including one million from the Ministry of Culture.

More science news can be found in the Lifestyle section.

ZAGREB, March 22, 2020 - Željko Reiner has been elected as a Fellow of the American Heart Association (AHA), the Croatian Academy of Sciences and Arts (HAZU) has said.

Reiner has been elected as a Fellow of AHA for his excellence, innovation and many years of contribution to science, practice and education in the field of cardiology, as well as his leadership in the field of preventive cardiology.

Founded 96 years ago, since 1950 the AHA has been publishing the most renowned cardiology scientific journal in the world, "Circulation", which called Reiner the pioneer of preventive cardiology a few years ago.

Reiner is now a member of the second most significant cardiology institution in the US, but also in the world.

In 2010 he was elected as a Fellow of the American College of Cardiology (ACC), which publishes the "Journal of the American College of Cardiology," the world's most widely read scientific journal in the field of cardiovascular diseases. Reiner has been a member of the journal's editorial board for many years.

As a member of HAZU, the Croatian Academy of Medical Sciences, an Honorary Fellow of the Academy of Medical Sciences of Bosnia and Herzegovina, and a Fellow of the Royal College of Physicians of London, Reiner became the only Croatian scientist and expert who is a fellow of all six renowned institutions.

More science news can be found in the Lifestyle section.

ZAGREB, March 7, 2020 - The European Space Agency (ESA) is counting on Croatia, Head of ESA Brussels Office, Michel Praet said at the end of a two-day workshop - "Space Powering Green Deal and Digital Economy" held at the Zagreb University Faculty of Engineering and Computing.

The two-day workshop on using space technology in collecting data on climate change was organised jointly with the Faculty, the European Space Agency and Croatia's Ministry of Science and Education and was held under the auspices of Croatia's presidency of the Council of the European Union.

The idea behind the workshop was to highlight the importance of space technology in the development of various industrial branches and it attracted leading Croatian and European researchers and entrepreneurs who, thanks to cooperation with ESA, have managed to launch and maintain successful companies.

Praet stated that he was honoured to work for the agency which has the ambition of using know-how in resolving problems and he believes that ESA is a fantastic tool in that regard. That is why, he added, he is proud that Croatia signed an agreement in 2018 to join the ESA and he is certain that Croatia can profit from Europe's space policy. That Cooperation Agreement with ESA signed on 19 February 2018, enables Croatia and ESA to create the framework for a more intensive and concrete cooperation related to ESA programmes and activities.

Science Ministry State Secretary Tome Antičić said that he was certain of good future cooperation between ESA and Croatia and that if Zagreb used that opportunity for cooperation, that can help the country to be much more successful.

More science news can be found in the Lifestyle section.

ZAGREB, February 4, 2020 - Croatian Science and Education Minister Blaženka Divjak said at an informal meeting of EU ministers in charge of research that brain circulation should remain one of the EU's cornerstones.

"We are encouraging mobility because those who are mobile and have experience from other countries bring that experience with them when they return. That way they make it possible for the system to be developed for the best, but we also want to attract others to work in Croatia," Divjak said at the meeting focusing on cooperation and researcher exchange and the future of the European Research Area.

European Commissioner for Innovation, Research, Culture, Education and Youth Mariya Gabriel said that not all countries benefited the same way from brain circulation in Europe.

We must reduce those differences between member states and promote international cooperation between researchers, she said.

Gabriel said that the budget for the Horizon Europe development and innovation programme would be increased, with original allocations amounting to around 3.3% of the EU budget, and that the Maria Sklodowska Curie research scholarship programme would continue as well.

Phillippe Busquin, European Commissioner for Research and Development, during whose term the European Research Area was established 20 years ago, said that before the establishment of the European Research Area brain drain from the EU to the USA had been much greater and that the EU had grown stronger as a science-research centre since.

More news about Croatia and the EU can be found in the Politics section.

ZAGREB, January 14, 2020 - Representatives of 550 Croatian scientists who signed the Appeal for Systematic Climate Action on Tuesday presented it to the government, parliament and Ministry of Environment and Energy.

The scientists claim that the current climate change is an emergency and the most serious and most complex crisis that mankind has ever been exposed to. That is why, with this appeal, they call on the relevant institutions to launch concrete and ambitious measures to deal with the problem.

All the graphs we get indicate that we are close to the dangerous limit of climate change when there won't be any chance of going back, Nikola Biliškov from the Ruđer Bošković Institute told a press conference outside Government House.

Scientists have pointed out very ambitious action on a global level with concrete objectives: to radically reduce carbon dioxide emissions so that this year they reach their maximum and then be reduced by 45% by 2030, while emissions should be entirely eliminated by 2050, Biliškov explained.

The appeal is a call on the legislative and executive authorities to adopt and implement ambitious policies as a precondition for systematically dealing with the climate crisis. Those policies need to be based on scientific research and lead to the development of efficient technical solutions to alleviate and adapt to climate change.

More science news can be found in the Lifestyle section.