Bill Gates’ talk on the first day of the TED (Technology, Entertainment, Design) conference got huge coverage, and within just a few hours some wag had turned Gates’ stunt of releasing mosquitoes into the audience into a Terry Gilliamesque game.

Some TEDsters might have felt depressed by talks on the economic crisis, our fragile environment, and war. PW Singer’s photos of battlefield robots – some to save and others to take away lives – raised the scary possibility that a solider might direct an assault online from an office in, say the US, and then go home to help his kids with their homework. Will the military be able to take full responsibility for their actions when warfare’s like that? And how will we define war crimes?

Most speakers showed obvious faith in mankind, however, and argued that bad times let us learn, act, and grow. Not for nothing is TED called Davos for optimists. Indeed, Rahm Emanuel’s advice to “never let a serious crisis go to waste” seemed particularly apposite (Emanuel, Barack Obama’s Chief of Staff, wasn’t at TED – he’s probably a bit too busy – but he was quoted in the programme).

Yann Arthus-Bertrand, the photographer whose book Earth From Above so compellingly captured our planet’s beauties and ills, argued that it’s simply too late to be pessimistic. It’s now time to face up to what needs to be done and get on with it. As he put it “we just don’t want to believe what we know”. To share some of what we know he recently launched 6 millionothers.org where 5000 short videos show people from all over the world answering simple but profound questions like “Who are you?” “What is love?” “What is happiness?” “What makes you cry?” and “What did your parents teach you?”

The next day Hans Rosling, professor of international health at the Karolinska Institute, had just six minutes to wow TED. He pulled it off with aplomb and wit. Rosling uses strikingly simple animated graphs to tell complex epidemiological stories. This time he summarised the entire HIV epidemic from 1983 to the present day, with a huge graph on which coloured blobs danced up and down to show how HIV prevalence has progressed in every part of the world, related to per capita income.

As Rosling clambered onto a table to reach the enormous screen above his head, he announced his own technological breakthrough “see, I’ve solidified the laser pointer”. (No not even TED has managed that yet: it was just a long pole, which he used to navigate us round his slide.) Laughter over, Rosling explained “It’s not respectful or clever to generalise when thinking about Africa”, particularly when looking at HIV infection. Prevalence varies in ways you might not expect. For instance, despite almost continuous conflict and ubiquitous rape, robust epidemiological studies show that the Democratic Republic of Congo has surprisingly low rates. Nor is there a linear association with poverty. The latest evidence, Rosling asserted, points towards concurrency – having several sexual partners at once – as an important cause of HIV infection. With such a brief talk and no question time, we were left to ponder the many social and immunological implications of that (and no doubt for some, religious and moral ones).

More medicine followed on Thursday, beginning with neurologist and writer Oliver Sacks on his own experiences of the visual hallucinations of Charles Bonnet syndrome due to ocular melanoma. Later Catherine Mohr, who manages to combine engineering expertise from MIT with surgical teaching at Stanford Medical School, gave a nicely non technical talk about surgical robotics. She’s director of research at the company that makes the da Vinci surgical system, which gives the surgeon three articulated robotic arms and a 3D camera plus screen for a wide range of operations, with some randomised trial evidence to back it up. Another Stanford doctor Daniel Kraft, had just three minutes to show us his neat invention, the marrow miner – a minimally invasive flexible device for harvesting bone marrow with greater efficiency and less pain for patients than the standard extractor.

Nicholas Negroponte dropped in to update us on the One Laptop Per Child (OLPC) project. There are now 750,000 of these affordable and almost indestructible computers in the hands of children in less developed countries, and half of these kids are teaching their parents to read and write. There was a pile of OLPCs in the TED bookshop for us to borrow and try out. When I opened mine on the bus back to the hotel, with the passenger next to me asking for a demo, I couldn’t operate it at all. It was so child-centred and so unlike a normal computer, I was stumped. Nor did I pluck up the courage to throw it hard onto the floor, like Negroponte did on stage.

Teachers using OLPCs say they love their jobs even more, not least because the kids’ behaviour in class is so much better than before. They bemoan, however, all the email they get from their students. Every silver lining has a cloud.

The next step, said Negroponte, is to let go – to build an olpc (yes, that’s deliberately in lower case letters) with open source hardware as well as software, so that companies all over the world will copy and disseminate it at low cost.

Not everyone managed a great unveiling through the week-long conference (which was their brief, and TED 2009’s overarching theme), but nearly all of the speakers had something of great value to share. Three had such big ideas that they won TED’s annual prizes, each gaining $100,000 to turn those ideas into action in the next 12 months.

US astronomer Jill Tarter is going to enlist all our help in studying the gargantuan dataset produced by telescopes for the Center for SETI (Search for Extraterrestrial Intelligence). The plan is to make the data openly accessible to ordinary people worldwide and to encourage both adults and children to delve in and try to spot patterns: something that computers, it seems, are less good at than humans. If you want to be the first to discover alien life, watch this infinite space.

Sylvia Earle, US oceanographer, is going to launch a global campaign to set up marine protected areas where ocean life can flourish once more. And José Antonio Abreu, Venezuelan economist, social reformer, and musician, is going to spread to the US and beyond his remarkably successful El Sistema project to help disadvantaged children become talented orchestral musicians.

If you’d like to know more about TED, and its upcoming conferences in Oxford UK and Mysore India this year and in Long Beach next year, go to ted.com

And for other BMJ blogs from TED see:
https://blogs.bmj.com/bmj/2009/02/06/trish-groves-at-ted-2009-4-february/
https://blogs.bmj.com/bmj/2008/02/28/tony-delamothe-at-ted/
https://blogs.bmj.com/bmj/2006/05/01/tony-delamothe-ted-2006-the-future-we-will-create/
https://blogs.bmj.com/bmj/2004/03/02/tony-delamothe-ted-2004-the-pursuit-of-happiness/

Trish Groves is deputy editor, BMJ