Gravity slows time. These are real, measured or calculated from Einstein's general relativity.
| Your life on Earth's surfacecompared with a clock far out in space | 22 ms slower a year |
| GPS satellitestheir clocks are built to make up for it | +38 µs a day |
| Astronauts on the ISSspeed wins over weaker gravity, so they age a little less | ≈ 0.01 s less a year |
| Surface of the Sun | 67 s slower a year |
| Surface of a neutron star1.4 Suns squeezed into a ball 24 km wide | 1 h = 1.24 h |
| Miller's planet in Interstellaronly possible near a black hole spinning almost as fast as nature allows | 1 h = 7 years |
Distances are in event-horizon radii, so the answer is the same for any non-spinning black hole. Below 3 radii no orbit is stable, and below 1.5 radii no circular orbit is possible at all. A spinning black hole lets you orbit much closer, which is how the film reaches seven years.
Every ray of light here is traced through curved space with Einstein's equations, the same physics behind the black hole in Interstellar. Fly close and watch light bend, time slow down and gravity stretch.