VENICE - “Gravity” opens, in coy denial of the mammoth imagery soon to follow, with modest white letters on a black screen, spelling out facts about outer space that sound more than a little like threats. “Life in space is impossible,” the titles conclude, after warning us off with daunting details of distance, physics and unimaginable cold. It’s a simple and – at least from a terrestrial perspective – pretty inarguable thesis that Alfonso Cuarón’s astonishing new film nonetheless goes to great, gruelling and frequently gasp-inducing pains to illustrate, before opening up less certain possibilities with a sudden surge in its own emotional temperature. Life in space is a no-go, sure. But what about life after?

It’s been seven long years since Cuarón, the serenely versatile Mexican stylist capable of finding grace notes in raunchy south-of-the-border road trips and Harry Potter alike, last visited our screens with a chilling fantasy that now sits as an unwittingly perfect bookend to his latest: in “Children of Men,” life scarcely seems possible on Earth.

Both films are visions of otherworldly worlds that look and sound nothing like their many previous cinematic realisations: industrial dystopia has never seemed less future-chic and more irreversibly barren than in “Men,” and space has never seemed bigger, more unknown, more outer than it does in “Gravity.” Both films navigate their unchartered territories with a hopefulness that could only be described paradoxically as despairing: for Sandra Bullock’s numbly bereaved medical engineer Ryan, as for the freakish newborn who emerges at the close of “Men,” survival is a short-term instinct with few known long-term rewards.

Meanwhile, life in space – impossible and urgently temporary as it may be – is pretty unbeatable, relieving its inhabitants of all accepted rules and limitations of physicality, movement and sound travel; it’s 45 years since Kubrick’s “2001: A Space Odyssey” effectively patented the description “the ultimate trip,” but that doesn’t mean Cuarón and his team can’t further serve and substantiate it. Certainly, the unfeasibly mobile camera of Cuarón’s loyal, invaluable cinematographer Emmanuel Lubezki seems drugged – or perhaps purely entranced – by its possibilities, gliding and weaving across seemingly impracticable distances with a deliberate fluidity that no previous screen depiction of weightlessness (whether in outer space or the subconscious hotel suites of Christopher Nolan’s mind) has come close to approximating. (You’d also have to go back to Wim Wenders’ “Pina” to find a film that demands this compellingly to be made and seen in 3D, and even that’s in a different ballpark.) When I stood up as the final credit rolled, I don’t mind admitting that I immediately had to sit down again, a Bambi-like wobble coursing through my limbs, as if I'd just re-encountered gravity myself. For sheer transference of experience upon the audience, I can think of no film quite like it.

Cuarón and Lubezki open the film straight away with a series of long, silky takes that luxuriate in gravity-free sensation, as three astronauts float with uncanny, disorientating ease through a routine spacewalk that only an astronaut could conceivably describe as “routine”. Ryan, on her first mission, at least has the good grace to look bewildered as they orbit their own spacecraft, bobbing and treading through the infinite blackness as through water; the more experienced Matt (George Clooney at his most glibly Clooney-esque, an atonal distraction that the film only gradually reveals as a virtue) banters with flirtatious geniality as she tetchily sets about her task, though it’s clear even he hasn’t become immune to awe in his privileged profession.

Guy Lodge is a South African-born critic and sometime screenwriter. In addition to his work at In Contention, he is a freelance contributor to Variety, Time Out, Empire and The Guardian. He lives well beyond his means in London.