Images Dated 19th September 2007

Helix nebula, infrared Spitzer image

Helix nebula (NGC 7293), infrared Spitzer Space Telescope image. This is a planetary nebula, a series of shells of gas cast off by a dying star. The ejection of the star's outer layers exposes its hot core, whose radiation ionises the shells, causing them to glow. This image was taken at wavelengths of varying energy: high (blue), medium (green) and low (red). The gas in the central regions has been ionised more than the outer gas, which is shielded from the stellar core. The most highly ionised areas (cometary heads) are round the edge of the central void. Foreground and background stars are blue. The Helix nebula is 650 light years from Earth, in the constellation of Aquarius. Image data obtained by the IRAC sensor in October 2004

© NASA/JPL-CALTECH/J. HORA (HARVARD-SMITHSONIAN CfA)/SCIENCE PHOTO LIBRARY

Envelope from Firminy, near Dunkirk, WW1

Envelope containing a letter dated 29 January 1915 from the architect and artist Ormerod Maxwell Ayrton (1874-1960) to his uncle Alfred Ayrton at Lloyds Bank, Chester, England, on the latter's birthday. The sender was stationed at Firminy, near Dunkirk, serving with the RNAS, HMA (His Majesty's Airship Squadron) No.17. Date: 1915

© David Cohen Fine Art/Mary Evans Picture Library

Poetry And Music. The Nine Muses Inspiring Arion, Orpheus And Pythagoras Under The Auspices Of The Personified Air, Source Of All Harmony. After A Miniature From The 13Th Century Manuscript Liber Pontificalis. From Science And Literature In The Middle Ages By Paul Lacroix Published London 1878

© Ken Welsh / Design Pics

Ages, Air, Arion, Illustration, Inspiring, Mediaeval, Medieval, Middle, Muses, Music, Nine, Orpheus, Personified, Poetry, Pythagoras