The main obstacle keeping humanity from enjoying the hoverboards and flying cars predicted in the 1989 Michael J. Fox film "Back to the Future II" is the earth’s plain-old gravitational pull, a York University astronomy and physics lecturer says.

“We have not figured out anti-gravity, I guess that’s the short answer there,” senior lecturer Paul Delaney said.

On the actual day depicted in the science fiction film, Oct. 21, 2015, modern science has not yet provided us with many of the things depicted in the movie, but Delaney says recent experiments have shown the ability to make objects hover, albeit in a limited space.

“The ability of metallic objects to use magnetism and be able to suspend themselves above tracks and so on, is in the realm of science, but not at the scale the film would have liked.”

A recent experiment by carmaker Lexus saw a “hoverboard” employ magnets and superconductors cooled with liquid nitrogen to glide across a specially-built, magnet covered skateboard park in Spain. But as soon as the board exits the magnetized skate park, it loses the ability to hover and strikes the ground.

“We’re a long way from the Marty McFly hoverboard, which is unfortunate,” Delaney said in an interview with CP24 Wednesday.

Robotic gas stations depicted dispensing hydrogen in the film have not yet come into common usage, but a television report from St. Louis, Missouri last year showed a gas station with an infra-red guided arm that could connect to a car’s fuel tank automatically.

Delaney said one related technology that the film did not foresee is drones.

“You and I can fly a drone relatively cheaply, for a few thousand dollars, and run it wherever we like with cameras and you can deliver things.”

Ottawa gets in on Back to the Future Day

In the film, Doc Brown, played by Christopher Lloyd, and Marty McFly, played by Michael J. Fox, use a heavily modified Delorean DMC-12 sports coupe to travel back and forth in time.

In the "Back to the Future" films, the nuclear-powered car must be travelling at least 88 miles per hour (142 km/h) to generate the 1.21 gigawatts of power needed to travel back and forth through time.

Transport Canada also got into the spirit of "Back to the Future" day and published a tongue-in-cheek recall Wednesday entitled “DELOREAN issued a recall on the DMC-12 model.”

“On a certain DMC-12 car converted into a time machine, a defect in the flux capacitor could lead to inability to travel through time while travelling at 88 miles per hour (141.6 km/h) and may increase energy consumption beyond 1.21 gigawatts,” the recall reads. “This could have disastrous consequences. Correction: Doc Brown will affect repairs.”

Delaney says comparing actual scientific progress to what is depicted in films is a natural human response, but shouldn’t make anyone feel like technology isn’t progressing fast enough.

“To compare the rates at which science fiction imagination works with science and technology, is really like (comparing) apples and oranges.”