how big is the gargantuan in interstellar

In Interstellar , the black hole Gargantua is about 150 million kilometers in radius , which is roughly the same as Earth’s orbital distance from the Sun (1 AU).

Size and mass

• Mass : Gargantua is modeled as a supermassive black hole with about 100 million times the mass of our Sun.

• Physical size : Its Schwarzschild (event‑horizon) radius comes out to around 150 million km , meaning the “surface” of the black hole is gigantic on a human‑solar‑system scale.

How that compares to real black holes

• Sagittarius A* (the black hole at the center of our galaxy) is only about 4 million solar masses , so Gargantua is much more massive than the Milky Way’s central black hole.

• However, even real behemoths like TON 618 (around 66 billion solar masses) are far larger than Gargantua, so in the real universe Gargantua falls somewhere in the “smaller” end of supermassive black holes , even though it’s already enormous by the standards of the film.

Why it’s that big in the movie

• The filmmakers chose this size and mass so that tidal forces near the event horizon would be gentle enough for Miller’s planet to exist in a close orbit, and for the time dilation (1 hour ≈ 7 years) to work out physically.

• In Kip Thorne’s The Science of Interstellar , he explains that a black hole this size makes the extreme time‑warp effects plausible within general‑relativity math , even if some visual aspects were toned down for the audience.

If you want, I can also break down the radius in more everyday terms (like how many Earths could fit across its “disk”).