It’s a question humans have asked forever. Are we alone in space? But it wasn’t until the late 1960s that humans started an organised, systematic hunt for extra-terrestrial intelligent life. We have listened to radio waves, peered through the celestial dust and beamed The Beatles to distant planets. So how’s it going? Is there anybody out there? This is the story of the search for extra-terrestrial life.

Presenter: Helena Merriman

(Photo: The ALMA, an international partnership project between Europe, North America and East Asia, with the cooperation of Chile. Credit to Getty)

Food production accounts for as much global greenhouse gas emissions as all forms of transport combined. That’s why many scientists think we can’t tackle climate change without addressing what we eat. So – in this week’s Inquiry – we’re looking at alternative climate-friendly diets and asking what it would take to move the world towards them.

Presenter: Helena Merriman

(Photo: Friends having a vegetarian meal. Credit: Shutterstock)

A lot has gone wrong this year. We are not talking about Brexit or the election of Donald Trump – both of which split opinion in Britain and the US. We are talking about terror attacks, the brutal conflict in Syria, and the thousands of migrants who died trying to reach Europe.

Good things did happen. But the good news was mostly buried under the bad. So we wanted to find about four things that went right in 2016. And, we talked to the people who made those things happen. Four amazing stories united by one thing - the ambition of a small number of extraordinary people to achieve the seemingly impossible.

It’s a surprisingly simple idea: to end long-term homelessness, give every person living on the streets a home. It can also be surprisingly effective. Medicine Hat, a city in Canada, recently became the first city to end homelessness in this way. The approach is known as Housing First, and – unlike many other homelessness initiatives – it doesn’t require homeless people to make steps towards solving other issues like alcoholism, mental health problems or drug addiction before they get a home. But is this approach solving the problem, or simply moving it off the streets?

Presenter: Helena Merriman

(Image: A homeless man with his dog outside a building. Credit to Getty)

We see and hear about Aleppo almost daily as news stories emerge of the hardship endured by its besieged people. After years of bombardment this once majestic place, the 'jewel' of Syria and one of the world's oldest inhabited cities, has been reduced to rubble. Thousands are dead. The residents who remain in the rebel-held parts of the city suffer from the ever-present threat of barrel bombs, while the international community has repeatedly failed to find a workable solution.

But why is Aleppo such an important part of the story of the war in Syria? The answer lies in Aleppo's historic role as a strategic city for so many people over the centuries, from Silk Road merchants of medieval times to the Assad regime and the forces currently battling for control of the country. Four Syrians, including one current Aleppo resident, tell us what life has been like in the city during its long and turbulent history.

(Photo: The Unesco-listed citadel (C) in the government-controlled side of the divided Syrian city of Aleppo. Credit: Getty Images)

Turkey first applied to join the European club over 50 years ago. Over the subsequent decades-long flirtation, enthusiasm for the EU in Turkey has remained high. Integrating with Europe, it was thought, would spur modernisation and economic development. But the country is changing under President Erdogan – who recently survived a coup attempt – in ways which deepen doubts in Europe about whether Turkey really shares its values. And enthusiasm in Turkey for the EU has begun to ebb away, as fewer and fewer Turks believe the EU will ever fully embrace them. So, our question this week: does Turkey still want to join the EU?

Presenter: Chris Morris

(Photo: European Commission President Jean Claude Juncker welcomes Turkish President Recep Tayyip Erdogan at the EU Commission in Brussels, Belgium, 05 October 2015. BBC Copyright, Elvis)

Trust in government is at an all-time low in many countries. From failed healthcare policies to missed intelligence, government blunders happen often – and visibly. But successful policy-making is hard (and fixes are rarely as quick as politicians like to promise).

Some argue that governments would do stupid things less often if they based their policies on the careful analysis of good evidence; find out what works, in other words, and then do that.

But that’s not how most governments operate, most of the time.

Why not?

Presenter: Michael Blastland

(Photo: a group of journalists being surrounded by the Media. Credit Shutterstock)

Hillary Clinton lost the US election despite some polls putting her chances of winning at 99%.

In the run up to the vote pollsters spent huge sums of money speaking to thousands of Americans. They were careful to collect the best possible data from representative samples, and they applied their finest statistical minds to analysing the numbers. Yet almost no-one predicted that Donald Trump would win. So – our question this week – why did the polls get it so wrong? Our expert witnesses explain why polling is getting harder, and why many pollsters weren’t – despite that – very far wide of the mark.

(Photo: Hillary Clinton and Donald Trump listen during the town hall debate at Washington University in St Louis, Missouri, October 2016. Credit: Getty Images)

Smoking tobacco is the single most dangerous voluntary activity in the world. It kills six million people a year, and if current trends continue that figure is expected to rise to 8 million people by 2030. Even if it does not kill you, it will give you bad breath, bad skin and cost you money. So why do so many of us still smoke?

(Photo: A man holds a cigarette over an ashtray. Credit: Patrik Stollarz/AFP/Getty Images)

On 8 November, as they stood in line to cast their votes, Americans were told by pollsters and pundits that, while close, the presidential race would be won by Hillary Clinton. As the results came in, precinct by precinct, many in the political establishment watched the unfolding story in disbelief. It was a similar feeling to that felt by many in Britain’s so-called ‘chattering class’ when, on June 24, they woke to the news that the UK had voted to leave the EU. Both were seismic political shocks. Neither was predicted by pollsters. What next? After two extraordinary electoral shocks, both of which challenge the established order, and with elections coming up in France and Germany, should we expect more?

(Photo: Republican Presidential nominee Donald Trump (R) greets UK Independence Party leader Nigel Farage at a campaign rally, Mississippi Coliseum. Credit: Jonathan Bachman/Getty Images)