Courses › The Universe from Scratch › Lesson 10
Real black holes · premieres Monday, November 9
A black hole is a region where gravity is so strong that not even light can escape. For decades they were only a prediction of Einstein's theory of relativity. Today we measure them, and we even have images of their shadow.
The masses, the distances and the way light bends are real. But the gas disk in these images is a textbook disk, and the colours are false, as in the telescope images. Real black holes spin; these do not. The background stars are placed at random and the jets are a schematic.
| Figure | Value | Source |
|---|---|---|
| Cygnus X-1 | 21.2 ± 2.2 M☉; 2.22 kpc ≈ 7,240 light-years; Schwarzschild radius 62.6 km | Miller-Jones et al. 2021; computed by the template |
| Sagittarius A* | 4.297 × 10⁶ M☉; 8,277 pc ≈ 27,000 light-years; EHT ring 51.8 ± 2.3 µas (2022) | GRAVITY 2022; EHT 2022 |
| M87* | 6.5 × 10⁹ M☉; 16.8 Mpc ≈ 55 million light-years; Schwarzschild radius 128 AU; ring 42 ± 3 µas (2019) | EHT 2019 (papers I and VI) |
| Calculated vs measured shadow | M87*: 39.7 vs 42 µas; Sgr A*: 53.2 vs 51.8 µas | Computed by the template (no spin) versus EHT |
| Pluto vs M87*'s horizon | Pluto ≈ 30–49 AU from the Sun < 128 AU | Calculated comparison |
| Light paths | Schwarzschild null geodesics | Luminet 1979; template integration |
They are Solaris Core Blender templates, built from measured data. You can download them, change the camera and make your own images.
See templates