Newswise — On a last-ditch effort to find humanity a new planetary home, astronauts in the blockbuster film Interstellar travel to the far reaches of space, enter a wormhole, explore strange planets, and get up close and personal with a black hole. But just how much of the movie is true to what we know about the universe? And how much of it is creative license?

To find out, the new blog Curious Stardust brought together three astrophysicists and bloggers for a live Google Hangout to separate Interstellar’s science from its fiction. (http://kavliblog.org/2014/12/19/interstellar-a-scifi-film-with-plenty-of-ifs/)

In all, the three agreed, significant thought and attention went into making a film based in real science and theory. Although there were a few noticeable holes in the science, Interstellar was more true-to-life than most science fiction films.

“I was actually very happy with the science and very happy to see something where these science concepts were put up on the big screen,” said Eric Miller, a research scientist at the MIT Kavli Institute for Astrophysics and Space Research.

Hardip Sanghera, a member of the Kavli Institute for Cosmology Cambridge, agreed, although he noted that not everything shown in the film is quite as scientists know it to be. “There were lots of ‘ifs’: if a black hole could capture a planet, if there’s such a thing as a stable orbit for a planet orbiting a black hole…” he said. “Yes, possibly these things could happen, but they’re probably extremely unlikely.”

The astrophysicists agreed that the most accurately portrayed science concept was the one that causes time to pass slower for the astronauts while they’re on a planet very close to a supermassive black hole.

“This is probably the biggest thing that really hasn’t been displayed before in movies, and that physicists are excited about,” said Mandeep Gill, an observational cosmologist at the Kavli Institute for Particle Astrophysics and Cosmology. “The concept is called time dilation by strong gravity.”

Such time dilation means that close to massive celestial objects, time is distorted and clocks run slower than they would otherwise. An hour near a very massive black hole could indeed equal seven years back on Earth, as happens in the film. This has even been proven experimentally. “In the 1970s, scientists took atomic clocks up in planes, and when they brought them down those clocks were running a little faster than the clocks on the ground,” said Sanghera. In fact, he continued, because GPS satellites orbit high above the Earth, their clocks run slightly faster and need to be adjusted to match time on the ground.

While the three astrophysicists were happy to see time dilation accurately portrayed, other science concepts were fictionalized for the sake of the plot. For example, no one has ever seen a planet orbiting a black hole. But that could be a reflection more of our instruments, not the universe. Experimentalists currently detect planets either by the wobble they induce on their sun or by a dimming of the light as they pass in front of their sun. In either case, such measurements are not possible if the planet orbits a black hole instead of a star.

It is also unlikely that humans could survive on a planet orbiting a black hole. “With a supermassive black hole like the one in the movie, you get an accretion disk: essentially material that’s being collected by the gravitational field of the black hole and is spiraling into the black hole,” said Miller. That matter gives off radiation, radiation that would make life quite difficult. “Any life would probably be fried,” he said.

Likewise, the end of the film (which won’t be spoiled here) was almost entirely science fiction, the astrophysicists agreed. Nonetheless, even considering these fictionalizations and embellishments, they all said they found Interstellar fascinating and enjoyable.

And, if they were to serve as science advisors to a future sci-fi film, what other concepts might they hope to include?

“For me, there’s the stuff that we know about in the universe, like magnetars and pulsars and extreme black holes,” said Gill. “But then there’s stuff… like dark matter and dark energy; these are very different and we don’t know too much about them. It would be neat to see that portrayed in some way. Will the universe expand forever? Is there a multiverse? There’s an amazing amount of stuff that we’re still discovering.”

A recording of the Hangout, as well as a modified transcript, is available at www.kavliblog.org.