Discovery

It's nearly a year (11 March 2011) since Japan was struck by a huge earthquake and Tsunami. Clouds of radioactive fall out from damaged nuclear reactors at the Fukushima Daiichi power station spread across heavily populated areas - many kilometres from the plant. The government and power company TEPCO have been heavily criticised for not telling the local population soon enough about what was going on - in many cases people evacuated to areas with higher radiation levels than those they fled. As a result, deep mistrust developed towards government or TEPCO pronouncements on the nuclear incident. In this special one hour edition of Discovery Mariko Oi, visits the Fukushima prefecture to find out what has happened since. She meets scientists working to piece together an accurate picture of the effects of the radioactive fall out, both on the environment and human health. She hears from local community grassroots organisations, many people living in fear of radiation, they argue for a mass clean up operation to reduce radiation levels to zero and further evacuations, especially of children. Mariko examines the current decontamination efforts, which involve removing and disposing of huge quantities of soil and concrete contaminated with caesium 137 – a radioactive isotope which can persist in the environment for 30 years or more. The programme questions whether attempting to remove such contamination is really effective - or even necessary, and contrasts the fears of radiation with the scientific reality.(Image: A journalist watching stricken Tokyo Electric Power Co (TEPCO) Fukushima Dai-ichi nuclear power plant at Okuma town in Fukushima prefecture. Credit: AFP/Getty Images)

Located in the western pacific, the Mariana Trench is the deepest part of the ocean, plunging down 11km. Down there it's pitch black, icy cold and the pressure is immense. Now explorers with funding from the private sector are planning to return to the bottom of the Trench, for the first time for over 50 years. Rebecca Morelle meets Jim Gardner, who works for the US Center for Coastal and Ocean Mapping, and has just completed the most detailed survey ever of the Mariana Trench, using sonar.Alan Jamieson, an ecologist at Oceanlab at the University of Aberdeen in Scotland, uses remote controlled submersibles to study the animals and plants that live at extreme pressure in the deepest parts of the oceans. He tells Rebecca why he believes it is preferable to deploy robots rather than humans to do this research. Legendary marine biologist and underwater explorer, Sylvia Earle, argues that it is essential for us to visit the depths of the ocean and see the extraordinary environment with our own eyes. As the former science chief for the National Oceanic and Atmospheric Administration, NOAA - the ocean's equivalent of NASA - Sylvia Earle says that the seas have always been the poor relation to space.Rebecca finds out from Bill Raggio of precision glass company Rayotek in San Diego, how to build a glass sphere for Triton submarines which will stop the three-man crew from being crushed by the pressure a the bottom of the Mariana Trench.And Sandra Brook from the Marine Conservation Biology Society talks about how research scientists may work with the commercial teams, like Triton, in the future as resources dry up for purely research submersibles.

Located in the western pacific, the Mariana Trench is the deepest part of the ocean, plunging down 11km.Down there it's pitch black, icy cold and the pressure is immense. The only time it was visited, was over 50 years ago by US naval lieutenant Don Walsh and Swiss engineer Jacques Picard. Now four teams of explorers are risking their lives in a new race to the deep. Rebecca Morelle travels to California to meet former property developer Chris Welsh who is hoping to travel by himself to the bottom of the trench in a five metre long torpedo like submarine equipped with wings and a tail fin. Her next stop is with the Triton team, who take her for a ride under the Caribbean sea in one of their submersibles, a prototype for the vessel that will be able to travel to the Mariana Trench. Rebecca also reports on a project being lead by James Cameron, the director of the film Titanic. And her final visit is to DOER Marine, where Liz Taylor tells her about the company’s plans to build a reusable submarine.

It sometimes seems to rule our lives and yet some scientists think it is an illusion. From birth to death we seem to be swept up in a relentless and inescapable journey through time, but what is this strange place we call the present moment? Why does the past seem fixed and the future so uncertain. Was the universe born into time or did time arise with the universe? Will time continue forever or will it fade like the stars? These are some of the questions that were discussed at a recent conference in Bergen and Copenhagen and on a ship between the two. In Discovery this week, science writer Zeeya Merali joins some of the leading physicists and cosmologists discussing the nature of time and its place in our lives and the Universe.Producer: Martin Redfern

Angela Saini explores the revolution taking place in the streets beneath our feet as she reveals the story behind a new urban design movement called shared space. She travels to The Netherlands where shared space was born, inspired by the radical traffic planner, Hans Monderman, who envisaged a world without barriers, signs, pavement and traffic lights. But not everyone is taken with this revolution, in particular the blind and visually impaired who say that shared space is fundamentally flawed and makes their lives less safe.

Geoff Watts meets researchers trying to find a new way to fight depression by studying those who never get it. In the second of two programmes Geoff meets scientists at the University of Manchester, studying the brains of people who have undergone traumatic life events without becoming seriously depressed and comparing them to the brains of those people who do. The hope is that new psychological therapies or even preventative medications might be developed to treat the one in five people who will at some point in their lives, become clinically depressed.(Image: MRI scan of the head and brain. Credit: Corbis Royalty Free)

Geoff Watts meets researchers looking for clues to the origins of depression as a way of finding new solutions to treating it. In the first of two programmes Geoff talks to the father of evolutionary medicine, Randolph Nesse and asks why hasn't natural selection made us less vulnerable to psychological diseases? Could it be that depression is in some way useful to our lives?(Image: A depressed young boy. Credit: Science Photo Library)

Exploring the past, present, and future of Seti, the podcast features insights from co-founder Frank Drake and active researchers Seth Shostak, Jill Tartar, and Doug Vakoch. They discuss the search for alien signals, communication complexity with extraterrestrial civilizations, boundaries of interstellar communication, and shared universal bonds.

In the first of two programmes, the BBC's science reporter Jason Palmer, meets the researchers behind Seti, the Search for Extra-Terrestrial Intelligence and looks at the prospects for success in the face of funding issues and the sheer size of the task. He talks to Seti's co-founder Frank Drake as well as its current active researchers, including Seth Shostak, Jill Tartar and Doug Vakoch.(Image: Computer artwork of our solar system. Credit: Science Photo Library)

For more than half a century aeronautical engineers have been working on the dream of hypersonic passenger flight. London to Sydney in four hours is an often cited goal. In Discovery Gareth Mitchell looks not at the past history of hypersonics, but at current developments. He meets engineers working on the propulsion systems and developing new materials specifically for hypersonic flight. Technologies which could be one applied to space craft as well as aeroplanes.