Entertainment

Time travel expert

‘We all wish for a back door in any situation when we’re up against it,” says Jason O’Mara, the Irish-born actor who stars as a time-travelling cop in “Terra Nova.”

Of course, O’Mara time-jumped as a cop before — in his last series, the ’70s-set “Life on Mars.” But this situation is different, he explains.

“Terra Nova” proposes a future where the planet is uninhabitable, and scientists have discovered a back door that goes back 85 million years.

“This settlement is essentially our best stab at ensuring the future of the human race.”

In “Life on Mars,” “Sam Tyler was just trying to hang on to his sanity,” O’Mara says.

“Terra Nova” is being shot in Bonogin, in Australia’s Gold Coast, where outdoor sets take advantage of the picturesque valleys and streams.

The prehistoric creatures, however, are the product of special effects, that require a special kind of acting.

“Thank God my co-star is Stephen Lang, the king of the green screen,” says O’Mara, referring to the “Avatar” actor’s experience with an environment added by the effects team in post-production.

Lang has given O’Mara tips to ensure they’re looking at the same thing — a tennis ball on a stick or a cut-out that’s waved around off-camera, for instance. But when O’Mara is sharing the frame with a dinosaur, visualization is key.

“You’ve got to imagine it’s really there,” he says. “I’ve been bitten, had parts of my clothing tugged.”