Author: BBC World Service

If you go outside with a spade and start digging, the chances are you won't find any gold. You might get lucky or just happen to live in a place where people have been finding gold for centuries. But for the most part, there'll be none. But why is that? Why do metals and minerals show up in some places and not others?

It's a question that's been bothering CrowdScience listener Martijn in the Netherlands, who has noticed the physical effects of mining in various different places while on his travels. It’s also a really important question for the future – specific elements are crucial to modern technology and renewable energy, and we need to find them somewhere.

Marnie Chesterton heads off on a hunt for answers, starting in a Scottish river where gold can sometimes be found. But why is it there, and how did it get there? Marnie goes on a journey through the inner workings of Earth's geology and the upheaval that happens beneath our feet to produce a deposit that’s worth mining.

On the way she discovers shimmering pools of lithium amongst the arid beauty of the Atacama Desert, meets researchers who are blasting rocks with lasers and melting them with a flame that’s hotter than the surface of the sun, and heads to the bottom of the ocean to encounter strange potato-sized lumps containing every single element on Earth.

And maybe, just maybe, she’ll also find gold.

Contributors: Leon Kirk, gold panning expert Holly Elliott, University of Derby Jamie Wilkinson, Natural History Museum, London Corrado Tore, SQM, Chile Yannick Buret, Natural History Museum, London Andrea Koschinsky, Jacobs University, Bremen

Presented by Marnie Chesterton Report by Jane Chambers Produced by Ben Motley for the BBC World Service

[Image: Hands holding Gold Nuggets. Credit: Getty Images]

Science in Action this week comes from a vast gathering of earth scientists in Vienna, at the general assembly of the European Geosciences Union.

Roland Pease hears the latest insights into the cataclysmic eruption of Hunga Tonga in the Pacific ocean from volcanologist Shane Cronin of the University of Auckland.

He also talks to NASA's Michael Way about how the planet Venus might have acquired its hellish super-greenhouse atmosphere, and how the same thing could happen to planet Earth.

There’s intriguing research from geologist John Tarduno of the University of Rochester that hints of a link between the ups and downs of the Earth’s magnetic field and the evolutionary history of animals.

Fraser Lott of the UK's Hadley Centre explains his ideas for calculating an individual person's responsibility for climate change-driven extreme weather events.

Image: Multi-beam sonar map of Hunga Tonga volcano post-eruption Credit: Shane Cronin/Uni of Auckland/Tonga Geological Services

Presenter: Roland Pease Producer: Andrew Luck-Baker

Tree mortality in tropical moist forests in Australia has been increasing since the mid 1980s. The death rate of trees appears to have doubled over that time period. According to an international team of researchers, the primary cause is drier air in these forests, the consequence of human-induced climate change. According to ecologist David Bauman, a similar process is likely underway in tropical forests on other continents.

Also in the programme: the outbreaks of monkeypox in Europe and North America… Could SARS-CoV-2 infection lingering in the gut be a cause of Long Covid? News of a vaccine against Epstein Barr virus, the cause of mononucleosis, various cancers and multiple sclerosis.

Digging and excavating are bywords for archaeology. But why does history end up deep under our feet?

This question struck CrowdScience listener Sunil in an underground car park. Archaeological remains found during the car park’s construction were displayed in the subterranean stairwells, getting progressively older the deeper he went. How had these treasures become covered in so much soil over the centuries?

CrowdScience visits Lisbon, the capital of Portugal – and home to the above-mentioned multi-storey car park. The city has evidence of human habitation stretching back into prehistory, with remnants of successive civilisations embedded and jumbled up below today’s street level. Why did it all end up like this?

Human behaviour is one factor, but natural processes are at work too. Over at Butser Ancient Farm, an experimental archaeology site in the UK, we explore the myriad forces of nature that cover up – or expose - ancient buildings and artefacts over time.

Image: Credit: Getty Images

Digging and excavating are bywords for archaeology. But why does history end up deep under our feet?

This question struck CrowdScience listener Sunil in an underground car park. Archaeological remains found during the car park’s construction were displayed in the subterranean stairwells, getting progressively older the deeper he went. How had these treasures become covered in so much soil over the centuries?

CrowdScience visits Lisbon, the capital of Portugal – and home to the above-mentioned multi-storey car park. The city has evidence of human habitation stretching back into prehistory, with remnants of successive civilisations embedded and jumbled up below today’s street level. Why did it all end up like this?

Human behaviour is one factor, but natural processes are at work too. Over at Butser Ancient Farm, an experimental archaeology site in the UK, we explore the myriad forces of nature that cover up – or expose - ancient buildings and artefacts over time.

Contributors:

Dr Mariana Nabais, University of Lisbon Carolina Grilo, Lisbon Museum of the Roman Theatre Dr Matt Pope, University College London

Presented by Marnie Chesterton, Produced by Cathy Edwards for the BBC World Service.

IMAGE: Getty Images

Tree mortality in tropical moist forests in Australia has been increasing since the mid 1980s. The death rate of trees appears to have doubled over that time period. According to an international team of researchers, the primary cause is drier air in these forests, the consequence of human-induced climate change. According to ecologist David Bauman, a similar process is likely underway in tropical forests on other continents.

Also in the programme: the outbreaks of monkeypox in Europe and North America… Could SARS-CoV-2 infection lingering in the gut be a cause of Long Covid? News of a vaccine against Epstein Barr virus, the cause of mononucleosis, various cancers and multiple sclerosis.

Image: Credit: Getty Images

Presenter: Roland Pease Producer: Andrew Luck-Baker

The heaviest thing in the Galaxy has now been imaged by the biggest telescope on Earth. This is Sagittarius A*, the supermassive black hole at the centre of our Galaxy – a gas and star-consuming object, a 4 million times the mass of the Sun. The Event Horizon Telescope is not one device but a consortium of radio telescopes ranging from the South Pole to the Arctic Circle. Their combined data allowed astronomers to focus in on this extreme object for the first time. Astronomer Ziri Younsi from University College London talks to Roland Pease about the orange doughnut image causing all the excitement.

Also in the programme…

Climatologist Chris Funk talks about the role of La Niña and climate change in the record-breaking two year drought that continues to threaten the lives and livelihoods of millions of people in East Africa.

Was a pig virus to blame for the death of the first patient to receive a pig heart transplant? We talk to the surgeon and scientist at the University of Maryland School of Medicine who led the historic animal to human transplant operation this year.

How easy will it be to grow plants in lunar soil on future moon bases? Plant biologist Anna Lisa Paul has been testing the question in her lab at the University of Florida, Gainesville, with cress seeds and lunar regolith collected by the Apollo missions.

And….

Does photographic memory exist?

Most people are great at remembering key points from important events in their lives, while the finer details - such as the colour of the table cloth in your favourite restaurant or the song playing on the radio while you brushed your teeth - are forgotten.

But some people seem to have the power to remember events, documents or landscapes with almost perfect recall, which is widely referred to as having a photographic memory. CrowdScience listeners Tracy and Michael want to know if photographic memory actually exists and if not, what are the memory processes that allow people to remember certain details so much better than others?

Putting her own memory skills to the test along the way, presenter Marnie Chesterton sets out to investigate just what’s happening inside our brains when we use our memories, the importance of being able to forget and why some people have better memories than others.

Photo: First image of Sgr A*, the supermassive black hole at the centre of our galaxy Credit: EHT Collaboration, Southern European Observatory

Presenter: Roland Pease and Marnie Chesterton Producer: Andrew Luck-Baker and Hannah Fisher

Most people are great at remembering key points from important events in their lives, while the finer details - such as the colour of the table cloth in your favourite restaurant or the song playing on the radio while you brushed your teeth - are forgotten. But some people seem to have the power to remember events, documents or landscapes with almost perfect recall, which is widely referred to as having a photographic memory.

Crowdscience listeners Tracy and Michael want to know if photographic memory actually exists and if not, what are the memory processes that allow people to remember certain details so much better than others?

Putting her own memory skills to the test along the way, presenter Marnie Chesterton sets out to investigate just what’s happening inside our brains when we use our memories, the importance of being able to forget and why some people have better memories than others.

Produced by Hannah Fisher and presented by Marnie Chesterton for the BBC World Service.

Contributors: Stephen Wiltshire Annette Wiltshire Dr Farahnaz Wick Professor Craig Stark

[Image credit: Getty Images]

The heaviest thing in the Galaxy has now been imaged by the biggest telescope on Earth. This is Sagittarius A*, the supermassive black hole at the centre of our Galaxy – a gas and star-consuming object, a 4 million times the mass of the Sun. The Event Horizon Telescope is not one device but a consortium of radio telescopes ranging from the South Pole to the Arctic Circle. Their combined data allowed astronomers to focus in on this extreme object for the first time. Astronomer Ziri Younsi from University College London talks to Roland Pease about the orange doughnut image causing all the excitement.

Also in the programme…

Climatologist Chris Funk talks about the role of La Niña and climate change in the record-breaking two year drought that continues to threaten the lives and livelihoods of millions of people in East Africa.

Was a pig virus to blame for the death of the first patient to receive a pig heart transplant? We talk to the surgeon and scientist at the University of Maryland School of Medicine who led the historic animal to human transplant operation this year.

How easy will it be to grow plants in lunar soil on future moon bases? Plant biologist Anna Lisa Paul has been testing the question in her lab at the University of Florida, Gainesville, with cress seeds and lunar regolith collected by the Apollo missions.

Photo: First image of Sgr A*, the supermassive black hole at the centre of our galaxy Credit: EHT Collaboration, Southern European Observatory

Presenter: Roland Pease Producer: Andrew Luck-Baker