June Gallery

10 Jun 1990

Action, F1, Formula 1, Gp

Human blastocyst

Light micrograph of a human blastocyst, an early stage of embryonic development, photographed 4-5 days after fertilisation. The blastocyst consists of a hollow ball of cells with a localized thickening called the inner cell mass (bottom left), which ultimately develops into the actual embryo. The remainder of the blastocyst (the thin part of the ball ) is composed of trophoblast tissue. Analysis of trophoblast cells has provided a novel means of pre-natal screening for genetic disorders. Initially unattached, the blastocyst soon becomes implanted in the wall of the uterus

© ANDY WALKER, MIDLAND FERTILITY SERVICES/ SCIENCE PHOTO LIBRARY

Computer simulation of solar oscillations

Computer simulation showing oscillations on the surface of the Sun. The Sun's surface is known to oscillate up and down like the surface of a wobbling jelly. The effect is due to the presence of sound waves of different frequencies, bouncing back & forth within the Sun. This simulation shows a combination of only 100 modes of oscillation; ten million different modes are known to exist. The height of the oscillations has been exaggerated by a factor of 1000 in this image. Each of these bumps moves up and down once every 5 minutes or so; the exact period of oscillation of each mode carries information on the structure & dynamics of the interior of the Sun

© DAVID HATHAWAY/NASA/SCIENCE PHOTO LIBRARY