August Gallery

10 Aug 1996

© EMPICS Sport

Hubble Space Telescope view of nebula NGC 604

Nebula in galaxy M33. Hubble Space Telescope (HST) image showing clouds of gas in the nebula NGC 604. This nebula is a region of intensive star formation. At the centre are more than 200 hot stars, each 15 to 60 times more massive than our Sun. High energy (ultraviolet) light from these stars heat the gas of the nebula and make it fluoresce. NGC 604 is about 1, 500 light years across, making it a peculiarly large nebula. It is situated in a galaxy called M33, found about 2.7 million light years away in the direction of the constellation Triangulum. This image was made on 17 January 1995

© NASA/ESA/STSCI/H.YANG, U.ILLINOIS/ SCIENCE PHOTO LIBRARY

Diagram of a device for opening doors

Door opening device. Diagram of a device designed by Hero of Alexandria (flourished 1st century AD) to open temple doors. As the fire on the altar (at upper left) heated the air beneath it, the gas expands and forces its way into the sphere (at bottom left). The sphere contains water which is forced out by the gas into the bucket. When enough water has flowed into the bucket, its weight will overcome that of the weight (at bottom right) holding the doors closed. The bucket will descend, pulling on ropes which are wound around poles that are attached to the doors and so open them. Intricate devices like this were popular in Hero's time. Image taken from Hero's Pneumatics

© SCIENCE PHOTO LIBRARY