The sky’s role in archaeology

In 1994, Czech poet-president Vaclav Havel wrote an article discussing the role of science in helping people understand the world around them. He also noted that in this advance of knowledge, however, something was left behind. ‘We may know immeasurably more about the universe than our ancestors did, and yet it increasingly seems they knew something more essential about it than we do, something that escapes us.’ Almost all traditional cultures looked to the sky for guidance. Cosmology is what gave our ancestors their fundamental sense of where they came from, who they were, and what their role in life was. While arguably incorrect, these ideas created codes of behaviour and bestowed a sense of identity. The cosmology of European prehistoric societies has been studied independently by archaeologists and archaeoastronomers (an interdisciplinary field between archaeology and astronomy). Despite their shared goal of shedding light on our past lives, thoughts, and ideas, the two fields have often failed to merge, mainly due to different approaches. A clear local case is the question of the Maltese megalithic temples.

Tore Lomsdalen

The Mnajdra South Temple on Malta predates both Stonehenge and the Egyptian pyramids. It is the oldest known site in the world that qualifies as a Neolithic device constructed to cover the path of the rising of the sun throughout a whole year. What is unfortunate is that, so far, archaeologists and archaeoastronomers have studied the site largely in isolation.

Whether the temples were built to visualise the effects of the rising sun as seen today is an open question. But with such specific and repetitive patterning, one cannot deny that the sky was an important element in the builders’ understanding of the world—their cosmology.

With some exceptions, archaeologists have largely ignored, excluded, or underrated the importance of the sky in the cultural interpretation of the material record. When studying ancient communities, chronological dating and economic concerns are often given precedence over the immaterial.

But the fault does not lie solely with disinterested archaeologists. Archaeoastronomy has often been too concerned with collecting astronomical and orientation data, neglecting the wider archaeological record, and ignoring the human element in cosmology.

We need to find a common ground. Both sides need to open themselves up to different professional perspectives and convictions and embrace alternative interpretations and possibilities. Bridging the gap between archaeology and archaeoastronomy will allow us to paint a detailed picture of past societies. And maybe it will shed light on that lost knowledge about the universe and our place in it.


Lomsdalen and Prof. Nicholas Vella are organising an afternoon workshop on Skyscape Archaeology as well as an open symposium on Cosmology in Archaeology. For more information, visit: um.edu.mt/arts/ classics-archaeo/newsandevents

  Author: Tore Lomsdalen

Understanding gravity to understand the universe

For a primate species clinging to a speck of dust in an incomprehensibly vast universe, curiosity has seen humans discover a great deal about how it all works. However, there are still mysteries that the cosmos is reluctant to relinquish, one of which is gravity. The most accurate theory describing gravitational attraction is general relativity, developed by Albert Einstein in 1915. Unlike Isaac Newton, Einstein did not describe gravity as a force, but rather a manifestation of the curvature of spacetime, thought of as a stretchable and squeezable fabric that is distorted by matter. However, his theory does not fully explain phenomena such as the accelerating expansion of the Universe and inconsistent orbital speeds of stars within galaxies.

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Extreme stars unlock gravitational secrets

Our understanding of gravity has changed over the years and will likely continue to as researchers arm themselves with new ideas tested by increasingly sophisticated technology. Dr Jackson Levi Said, Mark Pace, and Filippos Nachmias (University of Malta [UoM]) tell THINK more about their mission to unlock gravity’s secrets from neutron stars.

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Analysing Alice: Finding order in chaos

With every particle collision in the ALICE experiment, a terabyte of data per second is generated for analysis. But not all of it is essential information. David Reuben Grech speaks to Dr Gianluca Valentino and Dr Johann A. Briffa about their work in separating the wheat from the chaff and removing noise from two of ALICE’s 18 subdetectors.

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Curious matters

 Society is built on curiosity; the drive to find answers to life’s abounding questions. This curiosity continues to fuel our brightest minds today. Cassi Camilleri talks to ALICE experiment leader Prof. Paolo Giubellino about his work at CERN and how it impacts our daily lives.

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Further down the rabbit hole

The European Organisation for Nuclear Research—CERN—is synonymous with the world’s brightest minds, cutting-edge research and groundbreaking discoveries. Lars Lorenz interviews Dr Kevin Vella (Faculty of ICT) about the University of Malta’s involvement at CERN and its game-changing tech contribution to the ALICE experiment.

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ALICE’s Adventures in Switzerland

Hidden 175 metres below the Franco-Swiss border lies a feat of human ingenuity: the Large Hadron Collider (LHC). The LHC is the largest scientific instrument ever constructed, providing mankind with the ability to begin unravelling the very fabric of the universe and everything around us. Now, following long established links with the European Organisation for Nuclear Research (CERN), University of Malta has signed a memorandum of understanding for its scientists’ collaborate with the latest set of experiments at the LHC.  Words by Scott Wilcockson. Photography by Edward Duca.

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The Universe is Strange and Beautiful

Super dense stars shooting jets of radiation, black holes swallowing up stars, supernovae, and unexplained bursts of gamma rays. These are all examples of a ‘transient event’, an incident that lasts at most a few days. They are amongst the most powerful and mysterious phenomena in the universe, but from Earth they appear as ‘blips’ on our telescopes, making them very difficult to study.

Byron Magri (from the Astronomy, Astrophysics and Cosmology Research Programme (AACRP) and supervised by Dr Kris Zarb Adami) is shedding light on how to detect these fleeting wonders. His work is focused on fast transients that only last a few seconds.

Earth-based radio telescopes (aka antennae) are as big as they can get. The problem is that astronomers need bigger telescopes to produce higher resolution images to reveal finer details about these objects and find new discoveries. The solution is to use arrays of smaller radio antennae that are linked together. Interferometry is used to combine the data.

The technique uses enormous computing power to measure the radio waves phase delays being gathered by the individual antennae. Interferometry then overlaps and superimposes them to produce a stronger signal and an image with a much higher resolution.

For this technique to work, it must carry out all the calculations as the event is happening. The computer algorithm interpreting the data must also filter out all the noise due to the Earth’s atmosphere. To top it all off, the transient events need to be singled out.

To meet these challenges Magri used GPUs (Graphic Processing Units), which are usually used by hardcore gamers to power the most advanced graphics. The design of GPUs lends itself well to heavy numerical processing. Magri wrote an algorithm that acts as an inferometer on a GPU and he is testing it on data from the BEST-2 radio telescope array in Medicina, Italy.

Developing these algorithms is important to make future arrays larger. The next generation interferometer, the Square Kilometer Array, will have hundreds of antennae, meaning that information extraction will need to be extremely efficient and rapid. These algorithms are a keystone to maximise the potential of a €1.5 billion telescope to find more amazing phenomena in our universe.

 

This research was performed as part of an M.Phil. (Melit.) in Physics at the Faculty of Science. For more about Malta’s role in the Square Kilometre Array see pg. 14, Issue 02 of  Think magazine (http://bit.ly/SKATHINK).

LOOKING UP TO THE SKIES

Malta is involved in the creation of the largest telescope ever built, the Square Kilometre Array. The telescope will be composed of 10 million antennas, process petaflops of data per day, and cost 1.5 billion euros. When built the array will peer deep into space to see how the first stars were born and attempt to solve the riddle of our origin. Words by Dr Kris Zarb Adami and Dr John Abela.

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