My “SpaceNews” for the episode of “The Skyentists” that Kirsten and me released yesterday was to talk about the citizen science project that is running this Sunday, 21st June (Winter Solstice in the Southern Hemisphere) with the aims of measure the light pollution in Australia and New Zealand.
This citizen science project is also part of the Guinness World Records ™ Official Attempt for Most users to take an online environmental sustainability lesson in 24 hours.
As you know, I’ve been fighting the big problem of the light pollution for decades, and not only because it negatively affects us, astronomers, but also because of the huge environmental impact that the light pollution is, with plenty of negative effects in flora, fauna and our health, and on top of that it is a stupid way of wasting our resources (and MONEY) and contribute to CO2 emission.
Hence, I’m helping as much as I can to promote this citizen science project and make the people aware of what we are missing because we are not illuminating properly our cities.
This morning, Marnie Ogg, CEO of the Australasian Dark Sky Alliance, has been interviewed by the famous weather presenter, meteorologist and science communicator Nate Byrne in the public Australian TV channel, ABC, about it.
The Australian night sky is amazing, but light pollution can ruin the view.
This Sunday, citizen scientists are being urged to measure how light is affecting how we see the stars.@SciNate gets the lowdown from @DarkSkyAlliance.
And I’m very happy because, for some few seconds, I was on TV!!!
I’m very grateful to Niall Byrne (Science in Public), Tanya Ha, Nate Byrne and Marnie Ogg for using my images and videos for all of this, but also for crediting them.
So, now you know, this Sunday evening don’t stay inside your house: get your kids, your friends, your family, your parents, your boyfriend or your girlfriend and look at the sky to help us measuring the light pollution in Australia, and perhaps even beating a World Guinness Record!
Update: Below I compile the links to articles in the media that have used my images for talking about all of this.
Help measure who has the darkest skies in Australia, The Rural, 21 June 2020. (The same article has been published in a total of 33 newspapers!!! I’m not going to list all of those here, some of them are: Illawarra, Central Western Daily, Mudgee Guardian, Hunter Valley News, Bendigo, Glen Innes Examiner, Wauchope Gazette, Moree, Barossa Herald, Margaret River Mail, Walcha News, South Coast Register, Sunshine Coast Daily, Busselton Mail…)
A couple of weeks ago my six-year-old son had to make his first speech in front of his classmates. It is a very common practice in Australia and in other English countries: from a very young age students are encouraged to briefly and concisely discuss their thoughts regarding a particular topic in public. My son chose the topic “how can we care about the environment?”, that we developed together (obviously, you can’t ask to a six-year-old child to do something like this on his own the very first time). He rehearsed during days. In his speech my son wanted to emphasize “the 3 Rs“: “reduce, reuse and recycle.” It was evident that at some point during the course they had talked about it in class, and certainly sometimes during this year he had returned from school asking for “containers and cartons to reuse them in toys or ornaments”. Ecological and environmental awareness does exist in our society, and it is indeed encouraging to see young people very committed to that. But is it enough?
Brainstorming session compiling key topics to prepare my child’s speech “What can we do to take care of the environment?”
The environmental issues are widely complex and touch on social, economic, political, scientific and even religious aspects. The World Climate Summit that has been held in Madrid these weeks demonstrates the complicated interrelationship of interests that exist when we try to really take care of our planet. Many people think that they are doing something useful but at the end of the day these are just patches to clear their conscience about their lack of actions to attack the real problem. Now, during Christmas, we all live another example of these contradictions.
Christmas has always been my favorite time of the year. As a child I waited excitedly for the gifts of the Three Wise Kings on January 6th (that is the real moment kids get their Christmas presents in Spain, as the tradition is that they are brought by the Three Wise Kings, we imported Papá Noel – Santa Clauss just recently). This day was always a great party in our house, with lots of papers and boxes to be unwrapped. Despite living now in another continent, with a slightly different culture, I try to maintain this tradition and the illusion of Christmas for my son, like so many people sure does around the world. But this year the confluence of many factors (the World Climate Summit, the rise of climate change deniers, the disastrous fires that are plaguing Australia and making Sydney the most polluted city in the world on Tuesday Dec 10th, my outrage at others environmental factors that are not taken seriously, and my son’s speech) have made me rethink everything. How much garbage do we generate in a few days? Where is this consumer society taking us?
As I couldn’t travel to Spain in 2019 I bought online several books and notebooks in Spanish for Christmas. I placed the entire order together but each book or notebook (the three packages at the bottom are thin homework notebooks in Spanish for my son, all of the same course) has come in an individual cardboard box and with a lot of extra, unwanted advertising and papers inside ? How much extra crap are we generating? By the way, 3 more packages that had not yet arrived are missing in the photo.
Indeed, Christmas has become a time of waste. You have to buy more and more things, frantically decorating houses and cities, attending large banquets (business, family, friends) in a few days. What used to be a short period of one or two weeks has now extended over two months. The shopping centers are decorated before Halloween. And the “Black Friday” is now a common practice worldwide, with people buying plenty of things online that they don’t need (and that will delivered to their homes by workers who usually are in precarious working conditions, in a cardboard box that includes plenty of unwanted publicity and other papers). Here it is the first “R” my son pointed out: we must reduce the huge amount of waste that we create.
Of course, for years now many scientists including me have been pointing out that there is an increasing huge waste of resources (of money) in Christmas lighting. Light pollution is growingand, sponsored by the rise of LEDs, more and more Christmas lights are installed every year in our cities. I am the first one to enjoy a beautiful holiday lighting and I know that it attracts people to the streets for Christmas shopping, but aren’t they too much now?
During the last months we have seen some politicians of Spanish major cities boasting about “my Christmas lighting is the best”. The facilities began to be installed in September, with millions of LEDs everywhere. It has been estimated that about 10% of the annual electricity bill of a large city in Spain is going into Christmas lighting. Apart from the most correct use that money could be given, this means a great contribution of greenhouse gases to the atmosphere. And it is more: the scientific studies are demonstrating that LEDs (which are replacing the low-pressure sodium lights, the most energy efficient and the least polluting of lights) are substantially impacting the fauna, flora and ourselves. An increasing of cancers are being detected in places with excessive lighting. Blue light (the dominant one in most LEDs that are being installed in cities around the world) inhibits the creation of melatonin, which is the hormone that controls our sleep and circadian rhythm. Light pollution is another major environmental problem, perhaps not publicly known as other types of pollution, but that must be taken into account and mitigated with appropriate laws and regulations. On this point it is interesting to note that the Spanish Network of Studies of Light Pollution has requested this month the total paralysis and reconstruction of the Royal Decree in which the Regulation of energy efficiency of outdoor lighting installations is approved, as it contains fundamental errors and the complete absence of scientific criteria in its elaboration.
Protesters in Madrid during the UN Climate Summit COP 25, on Friday, December 6, 2019, with the contrast of the exaggerated lighting of Madrid’s buildings, even more for Christmas. I have not found the credit of the image, a thousand apologies to the author, although I asked on Twitter and tried.
As a scientist I don’t believe in climate change. I don’t believe in it because the verb to believe means “to have something for sure without knowing it directly or without it being proven or proven” (definition of the “Real Academia Española”, the “Royal Spanish Academy”). As a scientist who has read and contrasted the observations and studies that have been done on the effect of the emission of greenhouse gases in the Earth’s atmosphere by burning fossil fuels in human activities during the past 200 years, I do have the absolute knowledge that climate change is real. Scientists have been warning the society for decades, and we have clearly known that global warming is not due to external factors, such as changing the brightness of the Sun, the Earth’s orbit, or even the movement of the Sun around the Milky Way. Global warming and its consequences, climate change, is undoubtedly the product of human activity.
Comparison of solar irradiance on the Earth (yellow) with the average temperature of the planet (in red) since 1880. The thick lines show the average in periods of 11 years. Variations (maximum 0.15%) of the total irradiance of the Sun on Earth show the small oscillations of 11 years due to the solar cycle. The change in the brightness of the Sun does not explain the increase of around 1 degree Celsius of the average temperature of the Earth’s atmosphere from the beginning of the 20th Century to the present. Credit: NASA.
Our society is not environmentally sustainable. Crossed interests and our own daily habits make extremely difficult to solve the environmental problems. Maybe first we all have to become aware of them. During the World Climate Summit in Madrid the last weeks some absurd things have been proposed (such as removing the emoji of plastic bottles of non-reusable cups with plastic straws), interesting ideas have been discussed (such as green bus stops, investigations of bacteria that consume carbon dioxide, the most common greenhouse gas, or ecological bags) and very contradictory images have been seen (such as the large mass demonstration of young people with banners for a green and sustainable world in a Madrid absolutely overflowed with lights, and not just Christmas lights).
But the only way to really deal with the problem is to change our energy model. We must really invest in renewable energy (especially solar) and also in nuclear energy (which has been scientifically proven safe) and ban coal, gas, petrol and oil. Some politicians and governments (Germany, New Zealand) are taking the problem of climate change seriously and are proposing good measures. Other countries like Spain are there there. And some countries including the United States and Australia try to ignore it.
We are not going to destroy the Earth. Climate change affects us as a global civilization, but not the planet itself. Certainly, we are killing the Earth’s enormous biodiversity, but we, the human beings, will be the most affected because of climate change, with hundreds of millions, perhaps billions, of people who will have to escape from their homes, becoming refugees elsewhere. Wars will happen, water will be a luxury product, and our descendants will look at us without believing that we had in our hands to stop this madness and we did nothing to stop it.
There are many important problems in the world, and many others local problems that seem to be important but they may not be. But, with total certainty, the most important challenge that Humanity is currently facing is stopping, and I’m not saying inverting, global warming. Only the combination of the personal effort of every citizen by changing our exaggerated consumption habits and the institutional effort strongly promoting a change in the energy model of our societies can achieve this.
The Earth seen by Apollo 17 in the last crewed mission to the Moon. The photo was taken 5 hours after takeoff, on December 7, 1972. This image is known as “The Blue Marble” (Credit: NASA / Apollo 17).
I conclude with the same reflections that my six-year-old son left at the end of his speech. “No other planet in the Solar System, not even Mars, and none of the more than 4000 planets that astronomers have discovered around other stars are like Earth. We have to take care of our home world. It is the only Earth we will ever know. ”
Some few months ago I was interviewed by Zacha Rosen in the FBi’s Not What You Think radio show. I was talking about what a galaxy is, the feeling of seeing the center of the Milky Way close to the zenith for the first time, and the problem of the light pollution.
The show was broadcasted on FBI 94.5 FM at 10:30am Saturday October 22nd, Sydney time. It is also available as podcast from the Not What You Think webpage or using iTunes.
You can also listen to the 18 minutes interview here:
Thanks Zacha for this wonderful experience I hope to repeat in the future!
DPENGLISH: This story belongs to the series “Double Post” which indicates posts that have been written both in English in The Lined Wolf and in Spanish in El Lobo Rayado.
DPESPAÑOL: Esta historia entra en la categoría “Doble Post” donde indico artículos que han sido escritos tanto en español en El Lobo Rayado como en inglés en The Lined Wolf.
Unlike the rest of sciences, Astrophysics is not based on carefully experiments designed in a laboratory but in the direct observation of the Universe. Astrophysicists get their data via the analysis of the light we receive from the Cosmos. For achieving this we use extremely sensitive instruments that collect the light emitted by planets, stars, nebulae and galaxies. Certainly, there are some alternative ways to study the Universe besides using the light, as analyzing meteorites or moon rocks, detecting energetic particles such as cosmic rays and neutrinos, or perhaps even using gravitational waves if they actually exist. But the main tool astrophysicists have today to investigate the Cosmos is the study of the radiation we receive from the outer space. Light is the key piece of the Astrophysics we make today.
As the aim is to observe the very faint light coming from objects located even billions of light years away, astronomical observatories are built in relatively isolated places, which are typically located high over the sea level. To observe the Universe, we astrophysicists need dark skies that are not affected by the nasty light pollution created by our society. The inadequate use of the artificial light emitted by streetlight of the cities induces an increasing of the brightness of the night sky. This happens as a consequence of the reflection and diffusion of the artificial light in the gases and particles of dust of the atmosphere. Besides the huge economic waste that it means, light pollution also has a very negative impact on the ecosystem, increases the amount of greenhouse gases in the atmosphere, and drastically diminishes the visibility of the celestial bodies. Unfortunately the light pollution is the reason that a large part of the mankind cannot enjoy a dark starry sky. How is the firmament when we observe it from a dark place? This time-lapse video shows as an example the sky over Siding Spring Observatory (Australia), where the Anglo-Australian Telescope (AAT), managed by the Australian Astronomical Observatory (AAO) and where I work, is located. The darkness of the sky in this observatory allows us to clearly see with our own eyes the Milky Way (the diffuse band of stars that crosses the sky) and many other celestial bodies such as the Magellanic Clouds, the Orion and Carina nebulae, or the Pleiades and Hyades star clusters.
Movie: Time-lapse video “The Sky over the Siding Spring Observatory”. More information about this video in this post in the blog. Credit: Ángel R. López-Sánchez (AAO/MQ).
On the other hand, after traveling during hundreds, millions, or billions of years throughout the deep space, the information codified in the light that reaches us is disrupted by the atmosphere of the Earth in the last millionth of a second of its trip. Hence professional telescopes are built on the top of the mountains, where the atmosphere is more stable than a sea level. Even though, many times this is not enough: our atmosphere distorts the light coming from space and prevents the identification of objects located very close in the sky. New techniques have been developed for compensating the effect of the atmosphere in the quality of the light we receive from the Cosmos. In particular, the adaptive optics technique induces in real time slight modifications to the shape of the primary mirror of the telescope, and therefore they counteract the distortion created by the atmosphere. In any case, astrophysicists need to direct the light received by the telescope to a detector, which transforms light energy into electric energy. This has been the purpose of the CCD (Charge-Couple Device) chips, firstly used by astronomers, and later popularized in smartphones and digital cameras. Very sophisticated optical systems are built to direct the light from the telescope to the detectors. Some of the systems created to manipulate our collection and processing of light are based on optical fibres. This new technology has created the branch of Astrophotonic. Indeed, the AAO, together with the University of Sydney and Macquarie University (Australia), are pioneers in the field of Astrophotonic. The next video shows how the light from the Cosmos is studied at the AAT. First it is collected using the primary mirror of the telescope, which has a diameter of 4 meters, and then it is sent using optical fibres to a dark room where the AAOmega spectrograph is located. This spectrograph, which is a series of special optics, separates the light into its rainbow spectrum, in a similar way a prism separates white light into a rainbow. The separated light is later focussed onto the CCD detector.
Movie: Rainbow Fingerprints, showing how the light of distant galaxies in collected by the Anglo-Australian Telescope and directed to the AAOmega spectrograph using optical fibres. More information: at the AAO webpages. Credit: Australian Astronomical Observatory (AAO), Movie produced by Amanda Bauer (AAO).
Specifically, this video shows how astrophysicists analyse the light coming from distant galaxies to understand their nature and properties. In particular, the video reveals the final science quality spectra for two different types of galaxies, one spiral (top panel) and one elliptical (bottom panel), using actual data obtained with the AAT and the AAOmega spectrograph. The information codified in the rainbow fingerprint identifies each galaxy unambiguously: distance, star formation history, chemical composition, age, physical properties as the temperature or the density of the diffuse gas, and many more. All this information has been captured within a single ray of light that has travelled hundred of millions of years to reach us. Similarly, the properties of stars (luminosity, mass, temperature, chemical composition, kinematics, …), nebulae, and any other celestial body (planets, comets, asteroids, quasars, …) are analyzed through its light. And studying tiny changes in the amount of light we receive from nearby stars we are now finding thousands of exoplanets in the Milky Way.
The “rainbow fingerprints” video shown before includes only the observations of two galaxies, but actually the AAT is able to observe around 350 objects at the same time. This is achieved using the 2dF robot, which can configure 400 optical fibres within a circular field of view with a diameter of 4 full moons. The majority of the optical fibres are allocated to observe galaxies (or stars), but some few optical fibres are used to get an accurate guiding of the telescope or to obtain important calibration data. With this technology the AAT is a survey machine, and indeed it is a pioneer of galaxy surveys. Around 1/3 of all the galaxy distances known today have been obtained using the AAT. The most recent galaxy survey completed at the AAT is the “Galaxy And Mass Assembly” (GAMA) survey, that has collected the light of more than 300 thousand galaxies located in some particular areas of the sky. The next movie shows the 3D distribution of galaxies in one of the sky areas observed by GAMA. This simulated fly through shows the real positions and images of the galaxies that have been mapped by GAMA. Distances are to scale, but the galaxy images have been enlarged for a viewing pleasure.
Movie: “Fly through of the GAMA Galaxy Catalogue”, showing a detailed map of the Universe where galaxies are in 3D. More information in the Vimeo webpage of the video. Crédito: Made by Will Parr, Dr. Mark Swinbank and Dr. Peder Norberg (Durham University) using data from the SDSS (Sloan Digital Sky Survey) and the GAMA (Galaxy And Mass Assembly) surveys.
However, to really understand what happens in the Universe, astrophysicists use not only the light that our eyes can see (the optical range) but all the other “lights” that make up the electromagnetic spectrum, from the very energetic gamma rays to the radio waves. The light codified in the radio waves is studied using radiotelescopes, many of them located in the surface of the Earth. The study of the light in radio frequencies allows us to detect the diffuse, cold gas existing in and around galaxies, the coldest regions of the interstellar medium and where the stars are formed, and energetic phenomena associated to galaxy nuclei hosting an active super-massive black hole in its centre. Many technological achievements, including the invention of the Wi-Fi, come from Radioastronomy. The study of the infrared, ultraviolet, X ray and gamma ray lights must be done using space telescopes, as the atmosphere of the Earth completely blocks these kinds of radiation. As an example, the next image shows how the nearby spiral galaxy M 101 is seen when we use all the lights of the electromagnetic spectrum. Light in X rays traces the most violent phenomena in the galaxy, which are regions associated to supernova remnants and black holes. The ultraviolet (UV) light marks where the youngest stars (those born less than 100 million years ago) are located. Optical (R band) and near-infrared (H band) lights indicate where the sun-like and the old stars are found. The emission coming from ionized hydrogen (H-alpha) reveals the star-forming regions, that is, the nebulae, in M 101. Mid-infrared (MIR) light comes from the thermal emission of the dust, which has been heated up by the young stars. Finally, the image in radio light (neutral atomic hydrogen, HI, at 21 cm) maps the diffuse, cold, gas in the galaxy.
Imagen: Mosaic showing six different views of the galaxy M 101, each one using a different wavelength. Images credit: X ray data (Chandra): NASA/CXC/JHU/K.Kuntz et al,; UV data(GALEX): Gil de Paz et al. 2007, ApJS, 173, 185; R and Hα data (KPNO): Hoopes et al. 2001, ApJ, 559, 878; Near-Infrared data (2MASS): Jarrett et al. 2003, AJ, 125, 525, 8 microns data (Spitzer): Dale et al. 2009, ApJ, 703, 517; 21cm HI data (VLA): Walter et al. 2008, AJ, 136, 2563, ”The H I Nearby Galaxy Survey”. Credit of the composition: Ángel R. López-Sánchez (AAO/MQ).
In any case, today Astrophysics does not only use observations of the light we collect from the Cosmos, but also includes a prominent theoretical framework. “Experiments” in Astrophysics are somewhat performed using computer simulations, where the laws of Physics, together with some initial conditions, are taken into account. When the computer runs, the simulated system evolves and from there general or particular trends are obtained. These predictions must be later compared with the real data obtained using telescopes. Just to name some few cases, stellar interiors, supernova explosions, and galaxy evolution are modeled through careful and sometimes expensive computer simulations. As an example, the next movie shows a cosmological simulation that follows the development of a spiral galaxy similar to the Milky Way from shortly after the Big Bang to the present time. This computer simulation, that required about 1 million CPU hours to be completed, assumes that the Universe is dominated by dark energy and dark matter. The simulation distinguishes old stars (red colour), young stars (blue colour) and the diffuse gas available to form new stars (pale blue), which is the gas we observe using radiotelescopes. This kind of cosmological simulations are later compared with observations obtained using professional telescopes to progress in our understanding of the Cosmos.
Movie: Computer simulation showing the evolution of a spiral galaxy over about 13.5 billion years, from shortly after the Big Bang to the present time. Colors indicate old stars (red), young stars (white and bright blue) and the distribution of gas density (pale blue); the view is 300,000 light-years across. The simulation ran on the Pleiades supercomputer at NASA’s Ames Research Center in Moffett Field, Calif., and required about 1 million CPU hours. It assumes a universe dominated by dark energy and dark matter. More information about this animation in this NASA website. Credit: F. Governato and T. Quinn (Univ. of Washington), A. Brooks (Univ. of Wisconsin, Madison), and J. Wadsley (McMaster Univ.).
In summary, thanks to the analysis of the light we know where stars, galaxies, and all the other celestial bodies are, what are they made of, how do the move, and more. Actually, much of the research that we astrophysicists do today combines observing and analyzing light coming from very different spectral ranges, X rays, ultraviolet, optical, infrared and radio waves. In many cases, we are using techniques that have been known for only few decades and that are still waiting to be fully exploited. The detailed study of the light coming from the Cosmos will provide new important astronomical discoveries in the nearby future and, at the same time, will impulse new technologies; many of them will be applied in medicine and communications. The light techniques we are developing for Astrophysics will have a direct application to our everyday life and will improve the welfare state of our society, besides deepens the understanding of the vast Universe we all live in.
Last 23rd March 2013 I was invited to give a Public Talk at Sydney Observatory because of the Earth Hour 2013. More than 200 people attended this event, I have to say I think it was not because of me but because of the possibility of getting a somewhat darker sky than usual in the city center. Earth Hour is a worldwide event organized by the World Wide Fund for Nature (WWF) that encourages households and businesses to turn off their non-essential lights for one hour. The aim of this is to raise awareness about the need to take action on climate change and, in particular, the problem of the light pollution. The Earth Hour first took place in 31st March 2007 in Sydney, which has a participation of 2.2 million Sydneysiders. In 2008 many other cities around the world adopted the event, creating a movement in which now participates around 1 billion people in more than 150 countries.
What is light pollution? It can be defined as the excessive or inappropriate outdoor lighting. Common forms of light pollution include glare, sky glow, light trespass, and light clutter. As the International Dark Sky Association (IDA) specifies in its main brouchure
Urban dwellers everywhere are losing the ability to see planets and stars in the night sky. The spectacular view of the Cosmos that has inspired science and art throughout history is disappearing. The glow of uncontrolled outdoor lighting has hidden the stars and changed our perception of the night. Light pollution wastes energy ( = MONEY! ), harms ecosystems, increases greenhouse gasses, threatens astronomical research and affect human health. Better lightning is the solution! The problems from light pollution can be solved by utilizing efficient, modestly bright outdoor lighting fixtures that are directed toward the ground and shielded to control glare.
Empire State Building in New York city at night. The light pollution is a terrible problem in large cities, giving the sky that orange colour. Sadly, today many children think that this is the real color of the night sky. Picture taken in October 2004. Credit: Charliebrown7034 (Wikipedia).
Beside the negative effect that the light pollution has in the environment and its effects in animals and persons, I want to emphasize that its main consequence (at least, that which sadly is more important) is the huge amount of money which is wasted to illuminate the clouds and hide the stars. People around the world are realizing that this stupid kind of pollution has an easy solution. However it is responsibility of we, scientists, to talk about this to the general public and also to our Governments. Following the document Public Lighting—Energy Efficient Street Lighting published in July 2008 by the Australian Government,
In Australia, public lighting is the single largest source of local government’s greenhouse gas emissions, typically accounting for 30 to 50% of their CO2 emissions. There are 1.94 million public lights — one for every 10 Australians — that annually cost A$210 million, use 1,035 GWh of electricity and are responsible for 1.15 million tonnes of CO2 emissions.
Photos comparing the vision of the Sydney Harbour Bridge and the Sydney Opera House during the Earth Hour on 28th March 2003 (top row) and after that event (bottom row). All 4 images were taken from the same place using a camera CANON EOS 400D, 400 ISO, f10 and 20 seconds exposure. The decreasing of the light pollution (seen specially well in the clouds) is quite evident. Credit: Á.R.L-S. (AAO/MQ)
I emphasized, however, that the light pollution in Australia is (still) not bad at all. Australia has some of the darkest places on Earth (I was really impressed about how stars shine from the Australian Desert), are indeed Sydney, which has 4.5 million people, has by far better night skies that those seen from the city I’m from, Córdoba (Spain), with only 350 thousand people. As an example, just check this image I took in 2011 New Year Eve from the Opera Bar, just downstairs of the Sydney Opera House
Vision of the Sydney Opera House from the Opera Bar on the 2011 New Year Eve. It is just a 10 seconds exposure at f6.3 and 400 ISO using a CANON EOS 400D camera. The main stars of the Orion and Taurus (The Bull) constellations are clearly seen, as well as the Pleiades and even the Orion Nebula as a diffuse dot! Credit: Á.R.L-S. (AAO/MQ)
After discussing the light pollution, its effects and some projects aimed to reduce it, I used the second half of my time to talk about my research at the Australian Astronomical Observatory / Macquarie University. I explained what an astronomer usually does, where the Siding Spring Observatory is, and presented some results of my own research about star-formation in galaxies.
A moment during my Public Talk at Sydney Observatory on 23rd March 2013 just before the Earth Hour. I was explaining here the problem of the light pollution, although later I talked about my research and work at the Australian Astronomical Observatory and Macquarie University. Credit: Jeanette Landstedt (Sydney Observatory).
After the talk the participants enjoyed some stargazing using the amateur telescopes provided by the Sydney Observatory. I was among them and couldn’t stop talking to one and another group, as I was still being asked about what I said during my talk. It was great to be able to do this in the very relaxing atmosphere of an amateur observation. The only bad thing was that there was still a lot of light coming from the Moon, indeed, choosing the weekend before Easter for the Earth Hour was not good as it was not possible to really check the actual difference induced by the deficit of illumination in the sky.
A/Prof. Ángel R. López-Sánchez 