Lighting the way to darker skies

Dr Joseph Caruana

As the sun sets and the sky darkens, a black velvety curtain adorned with flecks of twinkling lights is drawn across the heavens, and a milky white band of fuzzy glow stretches majestically overhead. Unfortunately, this experience is nowadays denied to us thanks to artificial lighting. The sky is often left awash in a cold, jarring glow, making Malta one of only five countries whose citizens are denied the possibility of observing the Milky Way from their home.

A few select coastal sites remain where we can see the Milky Way. But even those are under continuous threat. In 2002 the Malta Environment and Planning Authority designated a number of sites in Gozo and Comino as Dark Sky Heritage Areas, stating that ‘reflective signs shall be employed to guide driving at night, whilst the installation of lighting which is not related to aerial or maritime navigation, shall be strongly discouraged.’ Since then, light pollution has still been increasing and is seriously impinging upon these areas.

To some, the ability to appreciate and study the night sky might be less of a priority, but light pollution affects our lives in many more ways. Our night-time environment is fast becoming a vista of blindingly cold light, and we need to act now to reverse this. Badly designed lighting can result in glare, which is especially dangerous while driving. Light trespassing into people’s homes creates a myriad of problems, ranging from mild discomfort to serious sleep disruption. Studies have linked bright LED lighting with adverse health effects, as it can interfere with our circadian (daily) rhythm. Light pollution also disturbs wildlife. For example, conserving colonies of birds that make their home at the cliffs of Dwejra, like Scopoli’s Shearwater and Yelkouan Shearwater, depends heavily on our efforts to curb light pollution.

The solution is not as drastic as switching off all our lights, but adopting full cutoff lighting in streets to illuminate the ground without spilling light everywhere else.

Luckily, light pollution is a reversible problem. Authorities can choose to bring about positive change, sometimes requiring little effort. Do we really need our public monuments, churches, building facades, and playing fields to be illuminated all night long, oftentimes with skyward-pointing floodlighting? When planning new lights for a road or a public space, should we not consider the impact the proposed lighting will have on the surrounding community and environment?

Conservation of our natural environment is not diametrically opposed to human activity and business interests. Other countries have long recognised the night sky’s potential for eco-tourism.

The Department of Physics (Faculty of Science, University of Malta [UM]) and Institute of Space Sciences and Astronomy (UM) are currently embarking on a new study of our islands’ night sky’s brightness. Interested parties, authorities, and non-governmental organisations alike are most welcome and encouraged to get in touch. It is only through awareness, dedication, and proper coordination that we can help ensure that future generations can still enjoy the peaceful beauty of the Maltese night sky.

Further reading: Falchi et al., ‘The new world atlas of artificial night sky brightness’, Science Advances, vol. 2, no. 6, 2016, e1600377

Author: Dr Joseph Caruana

The limits of noise

Of the astronomical phenomena, we can witness with our own eyes, a solar eclipse is one of the most spectacular. This phenomenon was used early in the 20th century to prove Einstein’s new theory of gravity. As light passes around a celestial object, its path is bent exactly as predicted by Einstein’s theory.

When researchers compared the amount light that was bent by large clusters of galaxies with the observed mass of the galaxies, they found that there was a discrepancy of over a factor of 1000, giving birth to the phenomenon known today as dark matter.

Deandra Cutajar

The distortions of galaxy shapes by large masses, provide astronomers with a tool to construct a dark matter map and its distribution in the universe we observe. Images captured using telescopes are analysed carefully to understand the distortions of galaxies due to the presence of dark matter lenses. However, in practice this is a very arduous task because telescopes suffer both from electronic noise as well as atmospheric distortions, so throughout my PhD, I investigated how the noise present in astronomical images could contribute to the distortion of galaxy images and also introduce errors in our maps of dark.

Under the supervision of Prof Kristian Zarb Adami, I applied Bayesian inference to determine the correct measurements of galaxy shapes. However, since the variations in the shape and size of galaxies due to lensing is very small, the measurement of dark matter is extremely difficult. Only novel statistical methods developed within a consistent Bayesian framework allow us to extract the maximum amount of information in such difficult scenarios.

Unfortunately, the application of the new methods in my Ph.D. have shown results that are similar to those reported by other researchers, with the techniques failing to provide the desired accuracy. Nonetheless research goes on, unravelling more mysteries and questions that still need answers.


On Qubes and the pockets that fit them

As far as tech trends go, smaller is almost always better. The team behind the University of Malta’s first ever PocketQube satellite agree-—–except when it comes to their ambitions. Cassi Camilleri speaks to Dr Ing. Marc Azzopardi, Darren Cachia, and Jonathan Camilleri to determine how work is progressing ahead of their 2018 space launch.

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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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Radio Telescope

Malta now has a radio telescope. This is a great step forward for the University of Malta as it helps speed up research.

The Department of Physics, Faculty of Science and the Institute of Space Sciences & Astronomy (ISSA; both at the University of Malta) have just acquired a 5.3m dual-reflector parabolic dish, as part of a European Regional Development Fund (ERDF) project to extend postgraduate research lab facilities. The radio telescope will now allow students and researchers to study celestial objects such as the sun or the centre of the galaxy through the radio waves they emit.

Quick Specs
Dish diameter: 5.3m

Feed horns: L-Band and K-band

Gain: 44 dBi @ 4GHz

Observing modes: Continuum and line observation

Total weight (including pedestal): 1900 kg

Surface accuracy: 0.5mm

PC-based automated control unit


toolkit02When pointed to a radio-loud celestial object (an object which emits large amounts of radio waves, such as the sun), the telescope will receive radio waves from these sources and convert them to voltage readings in the feed. The converted signal is then transmitted to a digitiser that converts these signals into bits and bytes.

The digitised signals are then processed and broken down into the different frequency counterparts (similar to what a car radio does with the radio waves it receives from its antenna), which allows for continuum observation of the skies above. The telescope provides a test-bed for several research initiatives being undertaken at ISSA.

Some of its specialisations include improving the hardware and software processing back-ends for radio telescopes. The on-site telescope can speed up this sort of research immensely. ISSA is part of the largest radio telescope project in the world: the SKA (Square Kilometre Array).

Galactic rotation dynamics in modified gravity

In the last 100 years, Einstein’s theory of general relativity has proven invaluable to explain the nature of the universe. That being said, Einstein’s model of gravity does at times fail to comply with what we actually observe when looking up at the night sky.

Galaxies offer one of the most impressive laboratories where general relativity just does not work. Stellar objects in galaxies tend to orbit the galactic centre of mass. General relativity predicts that as one goes further from the centre of the galaxy, these orbital speeds drop off. Observational data shows that these velocities tend to stay constant along the radius of a galaxy. However, dark matter can be artificially introduced to account for this. The other argument is that such failures indicate the inability of general relativity to fully explain how the universe works. If this is so, it seems necessary to construct what are called alternative or modified theories of gravity. Such theories would have to be capable of correctly explaining all observed phenomena including those that general relativity fails to produce.

Andrew Finch (supervised by Dr Jackson Levi Said) is looking into the new concept of treating gravity as a torsional dominated system instead of a curvature dominated one, which is the concept explained by general relativity. The new models are being developed with the intention of agreeing with galactic rotation curves while managing to explain everything that general relativity already does. It is only possible to vigorously test such models because of the large amount of freely available data which has been gathered on galaxies. As models are obtained, the cluster in the ISSA (Institute of Space Science and Astronomy) laboratory is being used in order to determine model parameters. Using this data, Finch aims to compare Einstein’s theory with the new model being developed. Will it improve on Einstein’s ideas? Only Finch will tell…

This research is being performed as part of a Masters Degree in Astrophysics being read at the Institute of Space Sciences and Astronomy, University of Malta.

Andrew Finch