Anglo-Saxon 10th century world map
Anglo-Saxon world map, dating from the 10th century. East is top. This map of the known world was probably produced by an Irish monk. Considering the state of European learning at the time, it is an impressive geographical achievement. However, in terms of accuracy it is outclassed by maps dating from the Classical era. Important landmarks, such as Jerusalem and Rome, are marked. The original is part of the Cotton Library, held in the British Library. Taken from A Book of Discovery (1912) by M.B. Synge
© SHEILA TERRY/SCIENCE PHOTO LIBRARY
Diagram showing the spectral class and luminosity of stars
Diagram showing the spectral class and luminosity of stars. The diagram was named The Hertzsprung-Russell Diagram, or the H-R diagram for short. At the beginning of the 20th century two astronomers found that if stars were plotted on a diagram with their luminosity (brightness) on one axis, and their spectral class on the other, that stars formed three distinct groups. The largest group, the Main Sequence Stars, is where 90% of the stars are found. These stars are fusing hydrogen into helium in their cores. This group propagates diagonally from the upper left corner, down to the right corner. The group below the main sequence is the White Dwarfs, which is a group of small, earth-sized stellar remnants. The third group, which is found above the main sequence is that of the giants.
Stars appear on a specific place on the main sequence depending on their mass and age. The mass determines when it will leave the main sequence.The H-R diagram is a significant tool for astronomers, when it comes to understanding stellar evolution
© Fahad Sulehria/Stocktrek Images
Salvation Army Social Campaign propaganda poster, London, c.1910 (chromolitho)
XND75970 Salvation Army Social Campaign propaganda poster, London, c.1910 (chromolitho) by English School, (20th century); Private Collection; (add.info.: In Darkest England and the Way Out.
A broadside on the Salvation Army's scheme to redress the social evils afflicting England; with a lithograph printed in colour, showing in the foreground a stormy sea ("Ocean of Misery") with a ship-wreck, the survivors being pulled from the sea by members of the Salvation Army and guided to an utopian England with solutions for all social problems; with lithographic titles, inscriptions, and Key to the chart in two columns. This chart is a pictorial representation of the benefits envisaged from the application of the Salvation Army's scheme for dealing with the social problems of Darkest England, as described in William Booth's book "In Darkest England and the Way Out" (first publ.1890), in which the chart was published. The ultimate solution to England's problems was emigration to the colonies.); English, out of copyright
incopyright but estate undetermined - possible copyright restrictions apply, consult orphan works legislation
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