Scottish director Danny Boyle's apocalyptic new movie, Sunshine, sees a band of astronauts try to reignite a dying sun in the year 2050. He talks to Michael Dwyerabout battling with studios, reinventing the sci-fi flick, and how his Ballinasloe mammy wanted him to be a priest

BRIGHT sunlight was streaming through the windows of Danny Boyle's Dublin hotel suite last Monday afternoon as he talked about his new movie, Sunshine. A stylish, fascinating and gripping science-fiction thriller, Sunshine is set 50 years in the future, and the sun is dying. Eight astronauts set out aboard a spacecraft, Icarus II, on a perilous mission to re-ignite the star with a nuclear device.

I mention to Boyle how everyone's going green, from Irish political parties as the general election looms, to the Hollywood stars who gushed pro-environment speeches at the Oscars last month and gave Al Gore a standing ovation when An Inconvenient Truth took the award for best documentary, even though they arrived at the ceremony in gas-guzzling stretch limos.

"And they all fly everywhere in their private jets," Boyle adds. "We could never compete with the Al Gore film, which I thought was sensational. I was absolutely dazzled by that film. I was dragged to see it. I thought it would be boring, but it was mesmerising. When we started work on this film three years ago, a lot of people said that it should be about climate change, the big issue, but we thought that by now everyone quite rightly would be worried about climate change. Even Bush has taken it on board.

"We were doing the opposite, which is looking at nature as the hostile force it can be and how it can destroy us in an instant. We wanted to see if science, having caused a lot of the problems on our planet, could actually get us out of a hole, which it will have to do. We have put all our eggs in the science basket. We are all committed to science now - apart from the Taliban, probably."

Sunshine marks an assured progress on to a broader canvas for Boyle after such relatively small-scale movies as Shallow Grave, Trainspotting, 28 Day Later and Millions. Refreshingly, it jettisons the cliches of the disaster movie, getting right down to business at the outset and staying in space without cutting back to earth for reaction shots of people watching TV news reports of the mission.

"They're the only notes you get from the studio," Boyle says. "They just want you to try and make it into something more like what they've had before, but we were absolutely adamant that there would be no cutting back to earth during the journey. All that flag-waving and cheering on the astronauts worked in Apollo 13 because it was a true story, but not in Armageddon.

"The studios are amazing in that they're willing to sacrifice anything to hope - plausibility, story structure, anything. We have a scene in the film where one character finds a little plant and then gets killed a minute later. They hated that because the plant represents hope, and we stamped on it."

Because there are so many special effects in Sunshine, Boyle felt a responsibility to explain scenes to his actors, and he found himself drawing on religion rather than science for reference points. "I realised that the vocabulary I was using was describing it as a religious experience. Cillian recognised that because he comes from a similar background to me."

At one point in his teens Boyle considered entering a seminary, but entered a cinema instead. "Quite a few directors nearly went that route - Martin Scorsese, John Woo, for example. Maybe it's got to do with the ceremony side of it. I was quite serious about it.

"My mother, God rest her, is from Ballinasloe, and she moved to Manchester in the 1950s. She was desperate for me, her eldest son, to be a priest. I was educated by Salesians and I was meant to go into the seminary at Wigan when I was 14. This priest took me aside and said he thought I should wait. Around the same time, I saw my first adult film, which was A Clockwork Orange. We couldn't believe we sneaked into it because there was so much sex and violence in it."

Sunshine marks Boyle's second collaboration with screenwriter Alex Garland after 28 Days Later, and he earlier directed the film of Garland's novel, The Beach. He describes Garland as "a very intellectual, aggressive atheist" and remarks that they had some vigorous debates as their ideas for Sunshine came together.

"Alex was drawn to the idea of somebody being the last man in the universe, whereas I was much more interested in the theme of growing close to the source of all life - in the solar system. Only a film can take you there, if you can manage it, to make you imagine for a moment what it's like to be there."

Isn't it tempting fate to name the spacecraft Icarus, given that it evokes Greek mythology in which young Icarus flies too close to the sun, which melts the wax holding his artificial wings together?

"That's interesting because I've done a lot of interviews about the film and, apart from a few French journalists, nobody else has mentioned this," Boyle says. "We did it deliberately, but most people haven't noticed it at all.

"There was a line in the film, which we cut, that it is named Icarus to remind the crew - and earth - of our humanity and humility, that this was an act of intense hubris to fly up to the sun and imagine that you can improve it or change it. It's typical of man's arrogance, and of science's wonderful but terrible arrogance."

Technology creates its own problems in effects-heavy movies, as the actors have to imagine what will be added in the elaborate post-production process. Many actors complain about how boring and patience-stretching that is. Boyle refers to this as "effectively a three-legged dog" because the visual effects aren't there yet. "You can see it in the faces of some actors," he says. "Their eyes look dead, or they overact."

He wanted Sunshine to be "more Nasa than Star Wars", adding that while he admired the first three Star Wars movies, he didn't like them. "I wanted to keep Sunshine as real as possible and to always have something there for the actors. Creating the sun was the biggest challenge, to make it as visceral an experience as possible.

"To do that with light is very difficult. Hot light is white, which gets very boring, so we made all the colours in the spacecraft blue, green or grey. For the benefit of the actors, we took a whole wall in what is the observation room and covered it in little discs of silver and gold, all twirling like in a 1970s disco. It cost only a few grand.

"Then Alwin Kuchler, the cinematographer, shone light at it, so we had these constantly changing lights to keep the actors entertained, and then we got those great shots of that light dancing in their eyes. You can't tell it's not the sun."

Sunshine opens on Thursday

The appliance of science fiction: Boyle's favourites

"They would be the big three - 2001: A Space Odyssey, Tarkovsky's original version of Solaris and the first Alien. I love those films and they were all benchmarks for Sunshine. They have set such a high standard that it can drive you mad making a film like this. There is no second place. You either get to that plateau, or else they don't quite work, as happened with Mission to Mars, Red Planet and a whole slew of them.

"The standard the audience demands now is really tough. You have to push and push to get there."

Sunshine inevitably recalls the three classics he cites. "They all boil down to three elements - a ship, a crew, a signal. Unless you do the film as fantasy, with creatures and stuff like that, you're left to work in a very narrow corridor and you're bumping into them the whole time. You would be having a conversation and then you realise that Stanley Kubrick must have had this conversation when he made 2001."

It's interesting that Boyle chooses the original Alien as he was offered the job of directing the fourth film in the series, Alien Resurrection. "I was briefly involved with that, but I really wasn't up to the CG then. I was right to back out of it because I'd have just drowned. The original script was much closer to the original Alien . . . But the studio wanted to turn the fourth Alien into something more like the second film, an action movie, and that's what it became."

"Cillian just has that look that you follow," Danny Boyle says.

"I wondered about casting somebody so bright, who also happens to be incredibly good- looking, as a scientist. In movies scientists are usually depicted as strange old grey men. But I was amazed at how much he looks like Dr Brian Cox, our scientific consultant on the film, who's around 40 and has played in D-Ream and other rock bands. Cillian even mimics him a bit in the film and borrows some of his mannerisms.

"It's always nice when you've enjoyed making a film with an actor, as I did with Cillian on 28 Days Later, and you get to work together again. I've really admired all he had done since we made that. I thought he stole the film in Batman Begins. I was amazed at him in Breakfast on Pluto, and that was only bettered by his performance in The Wind That Shakes the Barley.

"You can see that Cillian has made really good choices. With actors, it's very much about the choices they make. They make a mark and they get lots of offers, and it's what they choose that makes them interesting. It was a pleasure to work with him again. He's still quite a shy, modest guy.

"I wanted the cast of Sunshine to work as an ensemble, and he was perfect to lead an ensemble like that, to be the first among equals, which is what he is."