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Home > All Images > 2002 > December > 19 Dec 2002

Images Dated 19th December 2002

Choose from 25 pictures in our Images Dated 19th December 2002 collection for your Wall Art or Photo Gift. All professionally made for Quick Shipping.

Sori on a fern leaf, Polystichum Featured 19 Dec 2002 Print

Sori on a fern leaf, Polystichum

Fern sori. Coloured scanning electron micrograph (SEM) of two sectioned sori" (spore containing structures) on a leaf of the male fern Polystichum filix-mas. Sori consist of clusters of sporangia (brown, stalked). Each sporangium contains many spores (tiny spheres). When the spores are ready for release, the indusium (pale green) covering each cluster of sporangia uncurls in dry conditions. This drying also occurs in the wall of the sporangium which eventually, due to tension, splits and catapults spores away from the plant. Spores germinate on the ground to form the prothallus of a new fern plant. Magnification: x2 at 5x7cm size. Magnification: x5 at 3x7 inch print size."


Star formation simulation Featured 19 Dec 2002 Print

Star formation simulation

Star formation. Image 2 of 6. Computer modelof a 1.2-light-year-wide interstellar gas ball, 61, 000 years after it began collapsing, a processthat causes star formation. The ball contains 50solar masses of gas and collapses under its owngravity. Brighter areas have greater density. Thismodel used 100, 000 processing hours on asupercomputer at the United Kingdom AstrophysicalFluid Facility (UKAFF) at the University ofLeicester, UK. Simulations such as this increaseunderstanding of the chaotic process of starformation, and the likelihood of planetary systemformation. For a sequence showing star formationover 266, 000 years, see images R590/089-094

© Matthew Bate/Science Photo Library