/ 1 November 1996

Hubble’s close-ups show new worlds

HUBBLE’S Universe: ANew Picture of Space (published by Constable), at first sight, looks like a coffee-table book on space, with bright dramatic pictures that suggest sci-fi book jackets or New Age tie-dyed shirts. But the pictures, taken by the Hubble Space Telescope, are not simply beautiful – they are a way of understanding how the universe works.

Read with the captions, each full-page colour plate becomes a mental journey, much like looking into those seemingly flat pictures until a 3-D image appears. Here you don’t have to squint your eyes, however – you have to wrap your brain around the subject.

#Take, for example, plate 47: Black Hole in M87. When you look at the picture for the black hole, there seems to be none; instead, there is a mass of orange, brightening to a yellow then white spot in the centre.

But, as writer Simon Goodwin explains in the accompanying caption, we can’t see a black hole because it doesn’t emit light. “Black holes,” he tells us, “are formed when an object becomes so massive, or so small, that it can no longer withstand the pull of its own gravity. The object collapses to a mathematical point with no size and then nothing that gets too close can escape its gravitational pull.”

#A mathematical point with no size? Now that’s really cosmic.

But this point is, as Goodwin explains, the bright light at the centre. There is a lot of brightness where the black hole is, because gas and stars are being dragged into it, heating up so much that they are giving off light in the form of x-rays and gamma rays. The hole is dragging everything nearby towards it and swallowing it all up.

Goodwin goes on to show how astronomers work out that the light in the middle of the galaxy M87 – the central galaxy of the Virgo cluster of galaxies – is a black hole rather than a cluster of suns and to discuss some of the features of black holes.

#This process of explanation is used throughout the book, and though he can sometimes lose the astronomically illiterate reader when he blithely drops terms like “diffraction spike” or “jets of electrons”, Goodwin is usually accessible and clear.

The images also seem to have been chosen not just for their beauty, but to allow the reader to explore many different aspects of the universe. Some of the most spectacular images come from nebulae, which, according to the book’s glossary, are “huge clouds of dust and gas” and “thought to be the birthplace of virtually all stars”.

#The Hubble pictures show their different shapes – some are columns of red and green, another in the shape of an hourglass, fire- engine red with a bright blue eye and yet another in the shape of an egg, glowing with a neon turquoise light.

The colours all mean something – each indicates a different gas – and the swirl of colours and shapes shows the birth of stars and galaxies, the universe in the making.

So this is no mere coffee-table book – it’s more like a black hole: open it and you’ll be dragged into a whole new way of seeing and understanding the world.