1. An Account of the Late Surprizing Appearance of the Lights Seen in the Air, on the Sixth of March Last; With an Attempt to Explain the Principal Phaenomena thereof; As It Was Laid before the Royal Society by Edmund Halley from 1716 (Source: Philosophical Transactions (1683-1775), Vol. 29 (1714 - 1716), pp. 406-428)
2. Early study of Aurora borealis. Jean-Jacques de Mairan, 1733, Traité physique et historique de l'aurore boréale (engraved plate)
3. Auroral observers by Sophus Tromholt, 1885, Under the Rays of the Aurora Borealis: In the Land of the Lapps and Kvæns, Volume 1
4. Mosaic composition of five photographs taken in rapid succession with one second exposure of the same auroral arc. Carl Störmer, 1930, Photographic Atlas of Auroral Forms and Scheme for Visual Observations of Aurorae
5. Early Ionogram, 1944 by Canadian Radio Wave Propagation Committee, “Instructions for Observers: Canadian Ionospheric Stations” (Source: Edward Jones-Imhotep, 2017, The Unreliable Nation)
6. Blue Marble, the first photographic image of Earth seen from space, 1972, NASA
7. Satellite image composite, Composite of seven satellite pictures showing aurora across North America. The city lights clearly outline the continental United States. NASA, collage by E. H. Rogers. (Source: R.H. Eather, 1980, The Majestic Lights: The Aurora in Science, History, and the Arts)
8. A comparison of sunspots between April 1994 and February 1989 (Source: unknown)
9. Ionogram depicting shortwave propagation in ionosphere, 2012 (Source: University of Twente, Netherlands)
10. Radio telescope array image of radio galaxies, 2019. (Source: SARAO; NRAO/AUI/NSF)
2. Early study of Aurora borealis. Jean-Jacques de Mairan, 1733, Traité physique et historique de l'aurore boréale (engraved plate)
3. Auroral observers by Sophus Tromholt, 1885, Under the Rays of the Aurora Borealis: In the Land of the Lapps and Kvæns, Volume 1
4. Mosaic composition of five photographs taken in rapid succession with one second exposure of the same auroral arc. Carl Störmer, 1930, Photographic Atlas of Auroral Forms and Scheme for Visual Observations of Aurorae
5. Early Ionogram, 1944 by Canadian Radio Wave Propagation Committee, “Instructions for Observers: Canadian Ionospheric Stations” (Source: Edward Jones-Imhotep, 2017, The Unreliable Nation)
6. Blue Marble, the first photographic image of Earth seen from space, 1972, NASA
7. Satellite image composite, Composite of seven satellite pictures showing aurora across North America. The city lights clearly outline the continental United States. NASA, collage by E. H. Rogers. (Source: R.H. Eather, 1980, The Majestic Lights: The Aurora in Science, History, and the Arts)
8. A comparison of sunspots between April 1994 and February 1989 (Source: unknown)
9. Ionogram depicting shortwave propagation in ionosphere, 2012 (Source: University of Twente, Netherlands)
10. Radio telescope array image of radio galaxies, 2019. (Source: SARAO; NRAO/AUI/NSF)