Picture credits
The drawings are our own. The photos are from Wikimedia Commons, under Creative Commons licences (Attribution, or Attribution-ShareAlike), CC0, or in the public domain.
Photos
Black hole - Messier 87 crop max res.jpg
by EHT Collaboration, CC BY 4.0. Cropped and resized; no other changes.
Black Hole Desktop & Phone Wallpapers (SVS14146 - BH accretion disk viz desktop).png
by NASA's Scientific Visualization Studio - KBR Wyle Services, LLC/Scott Wiessinger, University of Maryland College Park/Barb Mattson, University of Maryland College Park/Francis Reddy, University of Maryland College Park/Jeanette Kazmierczak, Public domain. Cropped and resized; no other changes.
Artist’s impression of the Black Hole at the heart of M87 (eso1907c).jpg
by ESO/M. Kornmesser, CC BY 4.0. Cropped and resized; no other changes.
Illustration of Cygnus X-1 (2011-cygx1-more-1).tiff
by NASA/CXC/M. Weiss, Public domain. Cropped and resized; no other changes.
Artist’s impression of the system with the most massive stellar black hole in our galaxy (eso2408a).jpg
by ESO/L. Calçada, CC BY 4.0. Cropped and resized; no other changes.
Multiwavelength View of Sagittarius A* (51657196986).jpg
by NASA, ESA, SSC, CXC and STScI (via NASA’s James Webb Space Telescope account), CC BY 2.0. Cropped and resized; no other changes.
Stars around Sgr A* in July 2021 (eso2119e).jpg
by ESO/GRAVITY collaboration, CC BY 4.0. Cropped and resized; no other changes.
First image of our black hole (eso2208-eht-mwa).jpg
by EHT Collaboration, CC BY 4.0. Cropped and resized; no other changes.
Comparison of the sizes of two black holes- M87* and Sagittarius A* (eso2208-eht-mwe).jpg
by EHT collaboration (acknowledgment: Lia Medeiros, xkcd), CC BY 4.0. Cropped and resized; no other changes.
A New Age of Discoveries - Potw2010a.jpg
by Y. Beletsky/ESO, CC BY 4.0. Cropped and resized; no other changes.
Karl Schwarzschild.png
by Unknown photographer, Public domain. Cropped and resized; no other changes.
Our own drawings
- A simplified drawing of a black hole on a starry background. In the middle is a small black circle, the event horizon, with a dot at its centre for the predicted singularity. Around it is a larger dark disc, the shadow, about twice the size of the horizon, edged by a thin bright photon ring. A flattened orange disc of hot gas, the accretion disk, crosses in front, brighter on the left where the gas moves towards us. A faint glow above and below is the corona, and two narrow blue jets shoot up and down.
Our own drawing - A bar chart of black hole masses on a scale where each step is ten times the last. From lightest to heaviest: the lightest known, 3.8 Suns; typical Milky Way stellar black holes, about 10; Cygnus X-1, 14.8 to 21; Gaia BH3, about 33; the 2015 LIGO pair, 29 and 36; an intermediate-mass candidate, about 50,000; Sagittarius A*, about 4 million; M87*, 6.5 billion; Holmberg 15A, at least 40 billion; and TON 618, 66 billion.
Our own drawing - A vertical timeline: 1783, Michell’s dark stars; 1916, Schwarzschild’s solution; 1965, Penrose shows they can form; 1967, Wheeler names them, according to the Royal Society; 1971, Cygnus X-1 discovered; 1974, Hawking’s bet on Cygnus X-1; 2015, first gravitational waves; 2019, first picture, of M87*; 2020, Nobel Prize for Penrose, Genzel and Ghez; 2022, the picture of Sagittarius A*; 2024, Gaia BH3 announced.
Our own drawing - A drawing of Earth with telescope sites marked in Hawaii, Mexico, Arizona, Spain, Chile and Antarctica, each linked by dotted lines to a small black ring labelled M87*, 55 million light-years away. Text: in 2017, eight radio telescopes, timed together as one Earth-sized telescope. Not to scale.
Our own drawing - A wavy line that starts small and slow on the left, gets faster and taller towards a peak marked Merger, then quickly dies away, marked Ringdown. A note says it is an illustration only, not real data.
Our own drawing
The drawings are simplified teaching drawings, not to scale, made from the sourced descriptions on this site. Useless the eraser is the network’s own mascot. Fonts: Bricolage Grotesque, Newsreader and Kalam (SIL Open Font Licence), served from this site.