Scientific Scribbles

The voice of UniMelb Science Communication students

Gold, Neutron stars, and Eucalyptus trees

Gold is a chemical element. It has many wonderful properties – it is very soft and ideal for fabulous jewelries; it is a great heat reflector; a conductor for electricity; and very inert so it can stay shiny and bright after thousands of years under standard conditions. It is also a ‘precious metal’ with very limited above-ground sources (the third most rare metal on Earth).

Gold! Credit: Flickr; Licence: CC

No wonder why we need gold. But where does it come from?

 

The Big Bang

Everything in this Universe started from the Big Bang, around 13.8 billion years ago, including the gold.

Following that gigantic explosion, the Universe expanded and cooled down, and lightest atoms appeared – 90% hydrogen atoms and 10% helium atoms.

After a few hundred million years, earliest stars underwent constant nuclear fusions. These reactions forced light elements together to make heavier elements, following the periodic table. These early stars made elements from carbon, nitrogen, oxygen, all the way towards iron, the heaviest element that a star can make. Up to this stage, no gold anywhere in the Universe.

Star nuclear fusion simplified version (with a mass greater than eight times the sun). Iron is the end of the fusion process. Credit: Wiki Commons; non-commercial use; Author: R. J. Hall

 

For elements heavier than Iron, their productions required much higher pressure, temperature, and energy —bigger, cataclysmic explosions.

 

It takes a supernova, or two neutron stars

 

Iron has a very stable nucleus, which means the end of a series of nuclear fusions in a star. Without their fuel, a star soon collapsed and exploded as a phenomenon called a supernova. From the first ever supernova that occurred in our Universe, atoms of gold were manufactured and spread along with debris of star explorations.

Big stars, when they reach the end of their lives, will eventually explode. Even after million of years, Unprecedented X-rays and other kinds of energy still remain. Credit: NASA

 

On 17th of the October, a team of astronomers announced that they had detected gravitational waves again, and hence the first collision of two neutron stars we have ever seen. Apart from all other important reasons that make this discovery huge, the collision itself confirms another theory of the origin of gold in the Universe. Scientists monitored the afterglow from the collision to work out its chemical composition. After observed for four consecutive nights, they claimed the glow is the result of gold formation.

 

An artistic view of neutron stars colliding. This is followed by massive explosion, gamma rays, and of course, plenty of gold being made. Credit: NASA

A Neutron star is what is left from a supernova explosion, combined with gravitational collapse. It is the smallest and densest form a star can be. The intense energy created from a collision between them was also enough to create gold.

 

Whether the gold was made by supernovas or neutron stars, after several million years, gold finally reached our planet. The vast majority of it, along with other rare metals such as platinum, sank with molten iron to make the core.

 

More gold!

An article on Visual Capitalist claims that we had reached the maximum production of gold in 2015 based on a report from Goldman Sachs. It also estimates that ‘we will run of gold by 2030’.

Can we find more gold ores? The answer is yes.

 

Gold can be found every where on this planet. It is just not many of them are concentrated and suitable for mining. Credit: Wiki Commons; License: non-commercial reuse; Author: Kelvinsong

 

Gold can be concentrated from the seas. Since the same processes of gold depositing occur in both the ocean and on land, and 71% of the surface is covered by ocean, that is a significant area that is yet to be explored. Underwater gold mining robots are under developing and will be used in future.

More gold deposits can also be found in the plant’s core. Current scientific theories indicate that there is enough gold in the core by measuring the density of the core. The amount of gold underground is, in fact, enough to cover the surface of the earth with a 4-meter thick layer.

The problem is that the core is much deeper than we can mine. The deepest gold mine in the World is TauTona Mine in South Africa, which reaches 3.9 km below ground.

 

 

Gold in the trees

Australian researchers have found gold particles that are present in tree leaves, as an article published in Australian National Geographic magazine. Such as Eucalyptus tree, or so-called gumtree.

Researchers had confirmed that these nanoparticles that found in eucalyptus leave represented ore traces. Plants like trees with long roots that can delve very deep underground to search for water, and hence, they have the chance to encounter gold mines.

A giant tree like this can deliver its roots as deep as 40 metres under the ground. They are thirsty for water, but they are also able to transport tiny gold particles up to leave. Credit: Flickr; Licence: CC

Nowadays, the price of gold is around $1,300 per ounce, but the discoveries have declined almost a half (45%) over the past ten years, and typically, it takes a decade to go from discovery to full-scale gold mine. Despite the huge demand for gold, the decline in above-ground gold ore indicates a need for new exploration technologies for gold deposits. ‘But such technologies have been seldom reported’, the article says.

Overall, eucalyptus trees might offer an alternative way to find gold deposits, for those ones that might be overlooked by other detectors.

 

We are just too greedy to give up all chances for gold.

 

 

 

 

 

 


The only electron

Imagine you were a time traveller who could also live while time was reversing. Only every time you go back and forth, you are a different you. Doing it so many times, you now have a whole town of yourself, half of them doing things normally, and half of them walking, talking and acting backwards. I’m sure some of us would love to see a whole citadel of ourselves living working and interacting, but perhaps it wouldn’t last long before it drove you mad. Although its something that should remain in fiction, sometimes crazy ideas lead to interesting leaps in science.

 

In 1939, an excited professor and supervisor, John Wheeler called up his student Richard Feynman at a ridiculous hour. “Feynman, I know why all electrons have the same charge and the same mass” “Why?” “Because they are all the same electron!” “*gasp”.


This world line describes the path that a single electron takes through space and time.
Moving horizontally is caused by interactions with the forces of nature and collisions with photons, moving the electron around in space.
When the world line travels downwards, (backwards through time) it is a positron and when it travels upwards, it is an electron.

If we were to zoom closer in, to the inside of the red box, then all we see is 2 different electrons and a positron. If this were the case, but with 10^80 bends instead, then you would get around the right number of electrons in the universe, all accounted for by one unbroken world line.

Although there is currently no other good explanation for why these electrons are perfectly identical to any level of accuracy you can measure too, the one electron universe does have some holes. The most problematic one is that according to the electrons world line, there should be equal amounts of electrons and positrons. This is doesn’t seem to be the case, as we know electrons greatly outnumber their backward counterparts. So either the idea is wrong, or the all the missing positrons are hiding somewhere.

 

But Richard Feynman didn’t take the one electron universe as seriously as he took the idea of positrons being time reversed electrons. This insight was the inspiration for his future contribution to physics, where he later won the 1965 Nobel prize in physics with Julian Schwinger and Sin-Itiro Tomonaga. The Feynman diagrams he used, were a way of analysing the behaviour of subatomic particles by drawing out every possible interaction between the particles and photons, including ‘virtual particles’ which are undetectable by the outside world.

Feynman diagram of an electron pair interacting via a virtual photon. Combining figures like this one corner to corner would gives a trace of the electron through the universe in one long connected path, although this would be a great oversimplification. photo credit: Papa November, on wiki commons.
Complex Feynman diagram involving the Higgs Boson. Disclaimer: I have no idea what this diagram is showing, just for a visual of what these diagrams look like. photo credit: Harp, wiki commons

The one electron universe is considered rather ‘out there’, but it does raise some interesting thoughts. The electron that is all electrons, weaving through everything from your hat to your head and all other human beings, connecting us in one big incredible masterpiece.


Valuing the Services of Our Ecosystems

Photo: Paul Hanley

Stories about ecological restoration are the best. Tales of beaver reintroductions transforming landscapes and improving water quality, dams being de-commissioned to allow Salmon to swim free or urban streams being returned to their natural state are the types of stories that inspire me to study science.

Although these success stories are great, they only exist because we have degraded almost every part of our world in the first place. Why do we keep making the same mistakes over and over?

 

Valuing Natural Capital

One answer is that is because our global economic system doesn’t value natural capital, our environment, our soil, air, water and vegetation, in the way it ought to.

This has a two-fold effect; firstly, it means that the real costs, the impact of economic output, is not accounted for – In economic terms these are referred to as externalities. Think of habitat loss when a highway is duplicated, decreased water quality downstream when a forest is logged, seafloors being decimated by trawling and shipping channels. The common resources we share are being degraded because the negative externalities created by our economy are not being accounted for.

Secondly, the beneficial services that our natural capital provides are not often valued. They are often appreciated, but truly valued, no. We might appreciate a shady tree lined street in the city, but do we know the value of its shade for surrounding buildings, its cooling for the pedestrians bellow or its value for the biodiversity using it as habitat?

We are starting to.

Quantifying the value of ecosystem services is a booming multidisciplinary field of science. As nature is intertwined with every aspect of our lives it makes sense that ecologists or plant physiologists collaborate with psychologists, or engineers, economists and policy makers to measure and value how our natural capital sustains and fulfils our lives and economies.

The ecosystem services of the ocean are being increasingly recognised and valued, particularly the value of “blue carbon”. Photo: Paul Hanley

In 2011, the total value of global ecosystem services was estimated to be USD 125 TRILLION per year. This figure retrospectively keeps going up as scientists improve methods to quantify value, yet the value of the world’s ecosystem services is decreasing each year as we degrade ecosystems around the world further.

This begs the question, what is the point of quantifying the value of natural systems when they are still being degraded?

Although it can all feel futile, there are many stories of the positive environmental impact that are emerging from improved methods of quantifying ecosystem services giving value to natural capital. For instance, wetlands.

Wetlands buffer the effects of hurricanes by absorbing the physical force of storm surges and by reducing flooding. Natural wetlands are much more cost-effective than constructed vertical levees. While, recent research found that wetlands reduced damages to the US state of Maryland from Hurricane Sandy by 30% and overall reduction in damages of over $625 million.

Coastal Wetlands and Flood Damage Reduction from TNC Coastal Resilience on Vimeo.

This is research is valuable for the insurance industry who look for ways to reduce risk. If investment in wetland conservation and restoration reduces the damage to properties after natural disturbances then it reduces the amount of money that they need to pay out. This has given rise to new financial tools, such as resilience bonds, that incentivise investments into ways to reduce risk – and due to continuing research using natural capital is fast becoming the most logical way.

Infrastructure protection is one just one tool for measuring and creating value from the ecosystem services that marine and coastal ecosystems produce. Another is “blue carbon” which is the term for new research showing just how efficient vegetated coastal ecosystems like kelp forests, mangroves and seagrass are in sequestering carbon.

The Barwon River at Barwon Heads, hosting some of Australia’s southern most mangroves, provides countless ecosystem services. Photo: Paul Hanley

Carbon sequestration has long been the driver of creating payments for ecosystem services, as governments around the world have introduced emissions trading schemes that create incentives for reducing green house gases in the atmosphere. Reforestation schemes have worked to varying degrees of success, but the reimbursement is often not great enough to convince people not to use their land for growing crops.

In Australia, where we have lagged behind the rest of the world in pricing green house gas (GHG) emissions, we have one good new story. Reinstatement of traditional Aboriginal fire management in Ahrnem Land, where savannahs are burned in patches early in the dry season, has reduced emissions by almost 40%. GHG reduction is just one of the many ecosystem services that this renewed management practice creates.

Smaller scale fires means more habitat complexity and biodiversity and a return to traditional land management practices almost 50,000 years old.

 

While there are significant environmental challenges for the world, it is nice to focus on the success stories every once in a while.

 


Would you let a spy into your house?

I used to have a Poo Chi when I was little. A grey robot dog, with green ears. I named it “Spot”, after the yellow puppy, Spot, in Eric Hill’s children’s books. Original, right? They were my favourite books. Anyways, it was as close as I got to owning a pet dog.

Pink Poo Chi, via Wikimedia Commons

I never really felt a close connection with Spot. Sure, it was smart enough to sit, wiggle its ears and tail, and bark songs, but it wasn’t all that exciting. Being a youngling confuddled by technology, I couldn’t figure out how to get Spot to obey my commands. Eventually as Spot’s batteries died, so did its small place in my heart. The last of Spot’s fate was to collect dust at the bottom of my toy cupboard.

Modern robot toys are far more developed than back then. A measly robot dog is no longer as exciting. Kids nowadays prefer humanoid or dinosaur robots. To be fair, how cool are those?

Robots are generally invented to make our lives easier, to automate mundane tasks that would otherwise be unnecessarily time-consuming. Robot vacuum cleaners, lawn mowers, etc. While they do do their job, it’s so amusing to watch them bump around as they try to maneuver through the furniture. But other times, robots are invented for entertainment value, as with Spot.

Over time, those two concepts seemingly ravelled together to give rise to companion robots. Companion robots are perfect for elderly widows or only-children. They are able to interact with the user using simple pre-loaded phrases, walk around, and do tricks. Something excellent for those that are lonely and just want a friend.

However with the advancement of technology, newer models of companion robots are able to do much more. Some are able to navigate around the house, some recognise voices and facial features of users. Some even have the ability to connect to your phone and access the internet. Most of these ‘home’ robots also use a camera to aid in facial recognition and spatial awareness.

This is already spelling out trouble.

Kuri is home robot that is like an amazon echo mounted on top of an iRobot Roomba. But with ‘emotions’. And actively interacts with people in the house, and also has different greetings depending on which family member. Which can also capture ‘special moments’ with its camera eyes. Oh my gosh, it’s basically a secret spy pretending to be a home robot!

Heaps of things could go out of hand with these robots having access to all these and can potentially cause great harm. Yet maybe the pros of having a home robot outweigh the cons. They are pretty much a super compliant family member who doesn’t require eating food, and follows you while playing your favourite songs and audiobooks. As long as we are up-to-date with our privacy, and making sure that everything is secure, it’s safe to share warmth with a companion, who doesn’t feel it, but certainly gives it.

Although I didn’t have a particularly good relationship with Spot, to tell you the truth, I love my iRobot Roomba. Sometimes it loudly undocks to vacuum the floor, rudely waking me from my sleep. But it truly breaks my heart to see it tangled up in the plastic bags from our previous shopping trip. I’ve formed an uncanny fondness towards Roomba through the countless hours I’ve stared at it get itself into senseless trouble, i.e. getting trapped under the dining table.

iRobot Roomba, own photo

So what do you think? Is our future doomed to be taken over by super intelligent home robots? Or will they become important family members who will have a special place in our heart?


Are we removing the human from psychology?

What is science to you?

To me, science is where truth stands tall, looming over all petty human skirmishes and biases. Scientists test each other’s methods, making sure each experiment produces the same results no matter who does it, where, and when. But rigorous checking only propels them to do better. In an ideal world, science is the focus — not the scientists.

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At some point this year, I had to choose between majoring in Neuroscience or Psychology. I’ve always had a problem with psychology. So much of it is based on theory upon theory, and who said what. There is little agreement on who is actually right — only the pros and cons of each idea. To me, the facts are lacking.

A similar realisation swept the world six years ago. The concept of power poses, describing how certain postures giving rise to higher confidence, had just been born. Around this time, a variety of bizarre findings were coming to light — mainly in the field of psychology. You may remember headlines like: Ovulating women are more likely to wear red! Male college students with fat arms probably have particular political stances! CHOCOLATE MAKES YOU LOSE WEIGHT!

Amy Cuddy, the social psychologist who wrote about power posing, demonstrating a typical power pose at a TED talk. Credit: Wikimedia Commons (Erik Hershman)

Everything changed when three dissatisfied psychologists released False-Positive Psychology. They showed just how easy it was for researchers to achieve results that were unlikely to be true. They called this p-hacking, a widespread abuse of methodologies including the look-elsewhere effect and cherry picking. In 2015, another Science article revealed only 36% of 100 studies published in psychology journals were replicable — as opposed to 50% in medicine journals.

Why is this important? When researchers obtain results, they need to consider whether their results are true and show a phenomenon that actually exists. For example, proving that certain poses make people feel more powerful could be an effect that doesn’t exist for everyone, but only appeared because of a badly designed study: a false positive.

It’s like getting some friends to laugh at your bad joke then claiming that your joke is universally funny. Or if a doctor did a routine checkup on your uncle and told him he was pregnant. If other scientists carry out the same study, but cannot get the same results, then it could also point towards a “false positive”.


“Well, uncle, you see, it’s because you have back pain and have trouble walking. Your belly is pretty huge too. It just makes sense that you’re pregnant.” – An example of a false positive. Credit: Flickr (Spyros Papaspyropoulos)

Before this point, new discoveries in psychology outpaced the validation of those findings but statistics has always influenced psychology, ever since the lady tasting tea test. It was previously bad practice to make inferences from the lack of results. For example, had power poses yielded no effect, we could not explain why for certain. Now, we can make sound conclusions from research that shows no results through Bayesian statistics. Projects like the Retraction Watch and Data Colada also keep studies in check. It would be unfair to say that psychology hasn’t progressed extensively since Freud.

Then, as the complicated oxymorons that humans tend to be, we took one step forward and two steps back. The moment statistics revolutionised the field of psychology for the better, scientists became the target of science.

This is how Amy Cuddy, co-author of the power posing study, toppled from grace. She had followed similar methodologies to other psychologists at the time. But because she gave one of the most watched TED talks ever, she fell under global scrutiny for failures to replicate her study after False-Positive Psychology was published.

Cuddy became an icon for bad science, condemned by the rising wave of statisticians eager to showcase the power of their analyses. Her co-author renounced the findings of the power pose study. Fellow academics distanced themselves, silent and afraid.

In an ideal world, science is the focus — not the scientists.

How do we encourage others to pursue academia if scientists are quick to attack one another instead of the science itself? The problems with psychology lie as much within the research as with the researchers involved. In a field detailing the complexity of human behaviour, it’s not surprising that its results are just as messy — especially when the scientists themselves are prone to this complexity.

It seems that as long as humans are involved, perhaps science is inevitably personal.

But when all is said and done, psychology is a science — verifying the results that come forth is the first step of many. It’s up to us to separate the scientist from the science, to recognise the extent to which criticism should be personal, and ultimately strive towards doing better science together.

Passionate about how to do good science? Read this and this. Join PsychMAP for lively discussions about psychological methodologies too!
This post was inspired by this New York Times article.


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