Spirograph in the sky.Some 2,000 light-years from Earth, an elderly star has ejected its puffy outer layers to form a luminous, jewel-like ball of gas. Set aglow by ultraviolet radiation pouring out from the core of the aging star, this gaseous nebula--called IC 418--resembles a "spirograph spirograph /spi·ro·graph/ (-graf) an instrument for registering respiratory movements. spi·ro·graph n. An instrument for registering the depth and rapidity of respiratory movements. ", the pattern produced by the familiar drawing toy. The Hubble Space Telescope Hubble Space Telescope (HST), the first large optical orbiting observatory. Built from 1978 to 1990 at a cost of $1.5 billion, the HST (named for astronomer E. P. Hubble) was expected to provide the clearest view yet obtained of the universe. took pictures of the nebula nebula (nĕb`y  lə) [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. last year, and NASA NASA: see National Aeronautics and Space Administration. NASA in full National Aeronautics and Space Administration Independent U.S. released the images on Sept. 7. Astronomers more than a century ago dubbed such gaseous structures planetary nebulae because their disk like shape, as discerned in the telescopes of the day, reminded the researchers of planets. Over the next several thousand years, IC 418 will slowly disperse. The aging star then left behind--the remnant of a bloated star called a red giant--will collapse to become a white dwarf. It will take billions of years to completely cool and fade. Our sun will meet the same fate, but not for about 5 billion years. |
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