Hubble

Fülszöveg

A STELLAR NUIRSERY
The front cover shows a Hubble Space Telescope image of a star-forming region in the Eagle nebula, about 7,000 light-years away in the constellation Serpens. The columns are massive fingers of gas and dust, many light-years long, protruding from a vast cloud of molecular hydrogen. Within JMKtiK^k
these columns, the gas is dense '
enough to collapse under its y^jP own weight, forming "evapo- P^ rating gaseous globules," or EGGs. This is an ekrly stage of star formation: young stars continue to grow as long as they can accumulate material from their surroundings.
Ultraviolet light from hot, young stars nearby continuously "boils away" gas from the surfaces of the columns, causing the ghostly fringes visible around the columns' edges. As the thinner gas is thus evaporated, the denser EGGs are left behind, first as bumps in the

columns' surfaces and later as small fingers extending away from the larger columns. You can see some of these fingers near the... Tovább

Fülszöveg

A STELLAR NUIRSERY
The front cover shows a Hubble Space Telescope image of a star-forming region in the Eagle nebula, about 7,000 light-years away in the constellation Serpens. The columns are massive fingers of gas and dust, many light-years long, protruding from a vast cloud of molecular hydrogen. Within JMKtiK^k
these columns, the gas is dense '
enough to collapse under its y^jP own weight, forming "evapo- P^ rating gaseous globules," or EGGs. This is an ekrly stage of star formation: young stars continue to grow as long as they can accumulate material from their surroundings.
Ultraviolet light from hot, young stars nearby continuously "boils away" gas from the surfaces of the columns, causing the ghostly fringes visible around the columns' edges. As the thinner gas is thus evaporated, the denser EGGs are left behind, first as bumps in the

columns' surfaces and later as small fingers extending away from the larger columns. You can see some of these fingers near the bright star on the left side of the image. Later the EGG breaks away from the column alto-. ^ gether and forms its own
¦|||||||fl|| teardrop-shaped cloud. This
^^H^^Ht process may explain why stars
come in different sizes - when stars inside smaller EGGs have absorbed all the available ^ '"K material, they stop growing.
1 The back cover shows a
larger view of the top of the left column, showing several EGGs. Both of these images were taken by Jeff Raster and Paul Scowen of Arizona State University on April 1, 1995, using Hubble's Wide Field and Planetary Camera 2, and are courtesy of NASA and ST Scl. Before these images and others like it were made, astronomers had never been able to see the star-forming process in such detail.
I—irst proposed in 1946, funded and — designed in the 1970s, built in the '80s, launched in 1990 and repaired in 1993, The Hubble Space Telescope has only recently begun performing as it was meant to. In this book we see the first fruits of Hubble's long and difficult journey. The images now coming down to us from the Space Telescope are spectacular, dazzling, engrossing and of tremendous importance for science.
Everywhere it looks, Hubble is discovering new phenomena in space, clearing up old mysteries and creating new ones. Among its startling recent findings are:
• Extremely bright stars whose mass could be up to 200 times that of the sun
• Gravitational microscopes, in which a distant galaxy is hugely distorted and magnified by a gravitational lens
• The first direct observation of "core collapse" in a globular cluster (Ml5), in which the stars are huddled so closely together that they have stripped away each other's atmospheres and are reduced almast to their stellar cores.
• The first genuine brown dwarf candidate, a companion to the star Gleise 229 that appears to be 20 to 50 times the size of Jupiter
• Confirmation that quasars do indeed reside in galaxies - but not in the kind of galaxies we had always thought
• Discovery of the second known super-massive black hole at the center of a galaxy - an object in NGC 4621 with a mass roughly a billion times that of the sun. Or is it not a black hole but perhaps a supermassive disk? Vissza