ALEX FILIPPENKO, PH.D.


On this cruise, we will have the opportunity to potentially witness many stunning phenomena produced by the interplay of light with the atmosphere. These include not only rainbows, but also the related solar and lunar halos, sun dogs, and solar pillars. The physical origins of these and other phenomena will be explained, as will the colors of sunrise and sunset, the elusive green flash, and atmospheric mirages. We will also explore auroras, produced when energetic charged particles from the Sun get trapped in Earth’s magnetic field and subsequently collide with atoms and molecules in the atmosphere. Lunar eclipses and magnificent total solar eclipses will also be described; though these won’t occur during our trip, remarkably Australia will experience four total solar eclipses in the decade 2028–2038.


We expected the attractive force of gravity to slow down the rate at which the Universe is expanding. But observations reveal that the expansion rate has actually been speeding up over the past five billion years, a Nobel-worthy discovery. Over the largest distances, the Universe seems to be dominated by a mysterious, repulsive “dark energy” that stretches space itself faster and faster. The physical origin and nature of dark energy, which makes up about 70% of the contents of the Universe, should provide clues to a unified quantum theory of gravity. But our most recent measurements provide another surprise: the current rate of expansion is even faster than expected, perhaps showing that dark energy is growing stronger with time or indicating the presence of a new type of relativistic particle.


Albert Einstein’s general theory of relativity, which was published in 1915 and deals with the effect of mass on the shape of space and the passage of time, predicts the existence of ripples in the fabric of space-time emitted by time-dependent asymmetric massive bodies. Such gravitational waves were finally detected in 2015 and 2016 from several pairs of merging black holes, a fitting way to celebrate the centennial of general relativity. And in August 2017, astronomers announced the detection of a colliding pair of neutron stars with both gravitational waves and light. This event, which probably created a black hole, proved for the first time that gravitational waves travel at the speed of light; moreover, it led to the production of precious metals such as gold and platinum, whose origin was previously a mystery.


Lick Observatory, in the mountains east of San Jose, California, is a vibrant research facility at optical and near-infrared wavelengths, and the primary base for the University of California’s astronomy education and public-outreach efforts. Cutting-edge fields include supernovae (stellar explosions), Earth-like planets orbiting other stars, and giant black holes in the centers of galaxies. Many of the studies are long-term and time-intensive, making them difficult or not feasible to conduct with larger telescopes elsewhere. Lick is also used to develop new technology, such as laser guide star adaptive optics, producing very clear images of celestial objects. These important areas of research and instrumentation will be discussed in the broader context of astronomical investigations.

 

MARTIN GREEN, PH.D.


Solar cells are simple to use, just place in the sun and they will generate electricity for a warranted 25 years. However, understanding how they work requires some familiarity with the most exciting developments in modern physics.

The two giants of science, Isaac Newton and Albert Einstein, both made critical contributions at early stages of their careers. Although many earlier thinkers had tried to understand sunlight, Newton was the first to make real progress with his simple but ingenious experiments with glass prisms. In 1905, Einstein took our understanding to a whole new level when he showed light possessed properties unable to be explained by classical physics, sometimes acting as a wave and other times as a particle. This particle is now known as a photon. In 1924, this led to the even bolder suggestion that the other important player in solar cells, the electron, long thought of as a particle, could also act as a wave.

The new wave mechanics that resulted from this insight provided a concise way of formulating this wave/particle duality and exploring the consequences. It explained many earlier puzzles including the difference between materials already classified as metals, insulators or semiconductors, in terms of the ways electrons could be contained within these materials as waves. In the early 1940s, one semiconductor, silicon, then not widely used, showed a strong sensitivity to light, leading to the first silicon solar cells and attempts to understand what made them so light sensitive. This in turn led not only to practical solar cells but also to the microelectronics revolution and all this has made possible including computers, smartphones, the internet, Facebook and the wonders still to come.


Hydrogen and helium are by far the most abundant elements in our galaxy, formed in the primordial big bang, according to current cosmological models. Heavier elements, including oxygen, iron and silicon, a distant third, sixth and eighth in galactic abundance, respectively, were formed much later in the core of stars in the final stages of their life, then scattered through the universe in massive supernova explosions.

In the Earth’s crust, this ordering changes since lighter elements were driven off by the sun’s heat while much iron, the heaviest element occurring in any abundance, sunk to the Earth’s molten core. Oxygen is the element in highest crustal abundance, with silicon the second most abundant. Unlike elements such as gold and silver, silicon reacts too readily with oxygen to occur naturally as isolated silicon. Most rocks, however, consist largely of silicon atoms bound to oxygen with this combination accounting for 75% of the weight of the Earth’s crust.

To be used in solar cells, silicon needs to be separated from oxygen and converted to wafers of pure silicon. Trying to understand the light sensitivity observed in the early 1940s, silicon was found to have two types of properties attributed to different impurities. One type was called “positive” or “p-type” since becoming positive in voltage when illuminated, the other called “negative” or “n-type” since becoming negative! The strong light sensitivity occurred where these two regions joined. The “p-n junction”, serendipitously discovered in this way, has proved to be one of the most important inventions since the wheel, with two junctions used in each of the billions of transistors in a single computer chip.

In a way that will be clearly explained, solar cells use a single p-n junction, combining Einstein’s particle-like photons with the wavelike properties of electrons in silicon to convert sunlight to electricity with no moving parts or polluting by-products, and now also at very low cost.


The announcement of the first efficient silicon solar cells in 1954 made the front page of the New York Times, but silicon technology was still in its infancy and costs were high. A use was soon found in space, with cells first used on spacecraft in 1957. This was the main commercial application for the next 20 years.

With the oil embargoes of the early 1970s, many countries sought energy self-sufficiency. In the US, Jimmy Carter launched a large solar program resulting in standard designs for both the cell and its packaging. Extensive testing showed packaged modules should be very reliable, as experience has confirmed. Australia pioneered use in remote telecommunications in the 1970s, with this the key commercial market for the 1980s.

Already apparent was the way cell costs were reducing rapidly as the total number produced increased, with prices decreasing by over 20% for every doubling of this number. Since 1980, the price of solar panels has reduced a hundred-fold as the amount produced increased many thousand-fold. This learning experience is common to many other industries, although its continuation over four decades, right to the present, is unusual.

With declining US efforts in the 1980s, Japan took up the running. Exploiting the learning curve, Japan began a “million roof” program in 1994, with steadily decreasing subsidies encouraging solar installation on steadily increasing numbers of Japanese homes, targeting one million by 2010. The program was terminated in 2004 with systems on about 250,000 homes. However, the million-roof mark was met by both Australia and Japan in 2013.

Germany then came to the fore with a feed-in tariff scheme introduced in 2000, with a premium paid for solar electricity. This well-conceived scheme resulted in rapid cost reductions and was adopted by many other countries. Manufacturing also moved to low-cost regions of Asia, further accelerating progress.

Over recent years, power purchase agreements, where solar generated electricity is sold at an agreed price generally over 20-years, have increased demand and put further downward pressure on prices. In recent international auctions involving electricity supply under such agreements, solar has come in as the cheapest, about three times cheaper than electricity from a new coal fired power station.


Concerns over rapidly increasing global temperatures are leading to international efforts to rapidly cut back on carbon dioxide emissions.

Electricity generation is the largest single emission source due to the widespread use of coal and gas as fuels. Rapidly decreasing costs position solar cells to quickly make a strong impact. Solar is already starting to do this in two different ways, one “behind the meter”, on the customer’s side of the meter, and the other “in-front of the meter”, on the power company’s side.

About 4% of Australia’s electricity is now generated by small solar systems installed “behind the meter” on 1.7 million private homes. This percentage Is expected to grow to over 20% by the early 2030s as solar spreads to more homes and larger commercial rooftops. While commercial demand for electricity is reasonably well matched to solar generation, home demand is generally highest in the mornings and evenings with solar peaking in the middle of the day. Storage batteries in the home, such as the Tesla Powerwall, will become increasingly common to match supply and demand, although other strategies such as storing energy in the coolness of refrigerators or in hot water could also be effective. Scheduling non-critical loads such as pool pumping, washing and drying to periods of peak solar intensity is also likely to become increasingly common in the “smart home” of the future.

Also growing rapidly both in Australia and overseas is the installation of solar “in-front of the meter” in large fields owned by power companies. Battery storage may also be important here with pumped hydro storage another option for matching supply and demand.

Another large source of carbon dioxide emissions is from use of oil products in transport, with private passenger cars a major emission source. Increasing use of electric vehicles is expected to reduce oil use, with electric vehicles expected to account for a quarter of new car sales by 2030 and the majority by 2040. These can quickly reduce carbon dioxide emissions if recharged by solar, such as when parked in solarised parking stations or garages. Installing cells on the car body itself or as “solar paint” may also prove surprisingly effective, since providing enough energy for typical daily commutes. Another exciting development has been the recent Tesla promotion of an electric semi-truck matched with battery recharging at solar powered stations, locking in low fuel costs for the life of the vehicle.
 

ANGELA MOLES, PH.D., F.R.S.N.


Both Australians and visitors to Australia often assert that the biology of Australia is very different to that of the rest of the world. In this seminar, I will give an overview of some of the things that make Australia so special. Expect lots of pictures of beautiful Australian landscapes and the wonderful native plants and animals of Australia. I will also tell you about a study we ran to find out just how unusual Australia really is. In this study, we used global databases to determine whether the climate, soil, plant traits, vertebrate life history traits and ecological processes of Australia differ to those found in North America, South America, Europe, Asia and Africa.


Introduced species are the second biggest cause of extinctions worldwide, and are responsible for massive environmental degradation. I will talk about some of Australia’s fights with introduced species, but I also want to tell you something new and different — about how arriving in a new country affects the invaders.

Introducing species to a new environment creates excellent conditions for evolution, as the species are subjected to a different climate, different resources, and interact with a whole different suite of species. We found that 70% of the annual plant species that have been introduced to Australia have changed since their arrival. I will show you evidence that one species has changed so much since it got to Australia that it now qualifies as a unique Australian species.

If we can’t eradicate introduced species (and we seldom can), then it seems inevitable that they will eventually evolve to become unique new taxa (whether we like it or not). At this point, we will have to decide whether to accept them as new native species, or try to exterminate them. While most ecologists don’t like the idea yet, I think acceptance of introduced species is just a matter of time. I have been called a witch for these ideas before — bring on the arguments!


Have you ever travelled to an interesting tropical country and had to get an armful of vaccinations? Ever since the early explorers started travelling the world, biologists have thought that the struggle for life is more intense in the tropics, with tropical plants and animals having a higher risk of picking up nasty parasites or diseases, or being eaten by something.

The idea that interactions between species are more intense in the tropics was fundamental to many ecological theories, but had never been properly tested. So, I travelled for two years, measuring how much leaf area plants lose to hungry animals, and how well defended plants’ leaves are. I worked in 75 different ecosystems, including tundras in Greenland, Norway, and Alaska; savannas in Australia, Zambia, and South Africa; rainforests in Peru, Panama, China,P and the Congo; and, deserts in Israel, Australia, and America. Surprisingly, I found that plants are neither more heavily attacked in the tropics, nor more heavily defended.

These findings mean biologists need a new theory to explain why there are so many species in the tropics, and tells pharmaceutical companies that they will do just as well looking for bioactive compounds (e.g. that elusive cure for cancer) in their local ecosystem as they would in tropical rainforests. My seminar will include lots of pretty pictures, show you just how nasty plants can be (natural is not synonymous with healthy!), and introduce you to the useful concept of zombie ideas.


Plants are often thought of as existing passively in their environment. However, we now know that plants can actively respond to the presence of competitors, herbivores, and pathogens, and to changing environmental stresses, and these responses can be elegant and dramatic. I will discuss how the interactions between plants and their enemies and adversities drive evolutionary innovation and adaptations. I will also explore how these plant adaptations expressed throughout the evolutionary history of the Australian continent can help us to understand the remarkable diversity of Australia’s iconic plant groups.
 

VEENA SAHAJWALLA, PH.D., F.T.S.E.


Over the past decade, the average volume of waste generated by the world’s urban dwellers has doubled to 1.2kgs per capita/day (World Bank), much of which is landfilled. And the world’s landfills are packed with useful elements and materials like carbon, hydrogen, silica, titanium, and various metals and oxides that industries usually source from virgin raw materials. Learn how landfills can be "mined" and manufacturing and environmental issues can be coupled together to create solutions for the planet.


Much of the vast wealth of resources embedded in waste cannot be easily recovered using conventional recycling methods, because of the increasing complexity of the products and materials and the processes needed to harvest them. Learn how scientists are investigating complex waste at its elemental level and using precisely-controlled reactions to selectively break and reform the bonds between the many different elements within materials in our complex waste mixes to recover valuable substances. Get a first-hand account of the knowledge and innovation that create unprecedented new opportunities to gain cost-effective sustainable resources from the world’s landfills.


Recycled materials recovered from complex waste could be reintegrated into industrial processes and products through one of two pathways to production using green technologies. The first path involves investigating numerous industrial processes to identify opportunities to replace mined resources with resources derived from waste. The second path involves simple, small-scale green technologies -- micro-factories -- that will enable businesses and communities to recover resources from waste, almost anywhere in the world. Find out how these process modifications and the unique micro-factory model brings the solutions to the problems for the first time.


Australian scientists have innovated micro-factories, custom-designed small-scale units set up to transform waste into valuable resources. Learn where development and implementation stands now and about the work such micro-factories are currently doing. We’ll hear how micro-factories are configured to recover and handle a wide range of mixed and complex wastes that would otherwise go to landfills while creating jobs that require minimal training. Get the scoop on the practical and inspiring work of materials science to improve the world we all live in.