Thorne theorized a temporary state whereby a black hole could accommodate human entry without emitting deadly radiation.

Space travel over great distances would be impossible without some way to speed up travel. Hence, the appeal of such phenomena as black holes and wormholes. In attempting to find a possible way to utilize these very great space hazards to speed up space travel, Interstellar’s theoretical physicist, Kip Thorne, has described the theory by which he could rationalize a relatively cooperative or hospitable black hole:

Scientific American interviewer

One of the main criticisms I had of the film when I first saw it was that the accretion disk around Gargantua was energetic enough to provide light and heat for its orbiting planets, but not so hot and bright that it would bathe the astronauts in fatal x-rays and gamma rays. But you’ve explained in your book how this isn’t as implausible as it may seem.

Kip Thorne, Theoretical Physicist, “Interstellar” advisor

Gargantua’s disk is anemic, meaning it’s not as dangerous as the black-hole accretion disks astronomers can see and study. It has the temperature of the surface of the sun. With our current technology, astronomers can’t really see an accretion disk of that temperature if it’s around a very massive black hole at the center of some galaxy. Instead, the accretion disks astronomers see are much more energetic and emitting lots of x-rays.

I worked out the relativistic theory of thin accretion disks with Igor Novikov back in the early 1970s, so I know this very well. For those energetic disks astronomers see, the accretion is a steady state where the gas is flowing onto the disk and on down to the black hole. You can work out the temperature distribution and where it is emitting hard and soft x-rays. In the film, the disk is orbiting the black hole, not accreting onto it. There is a reason you don’t see any flow of gas onto the black hole in the movie, because if that flow were there it would fry the astronauts. Gargantua’s disk is a remnant of what was in the past an accreting disk. It’s in a quiescent state and cooling down.

This was a crucial detail that actually dovetailed with Chris’s filmmaking point of view. What Chris wanted was something that was visually impressive in optical wavelengths that the astronauts could see. So that’s what he got – something that glows in the optical but isn’t so hot it pours off a lot of dangerous higher energy radiation. Let me say, though, that this particular quiescent and cool disk wouldn’t be in this state for an awfully long time. But, ha, all that the movie needed was a safe, bright environment around the black hole during the crew’s visit, and this disk meets that.

Click next page to see the transcript of a somewhat lengthy video, and optionally, the video itself, where three scholars examine the science behind the movie, “Interstellar.” This engaging video was made before Thorne’s explanatory book was published.