From the Hubble Space Telescope
This NASA Hubble Space Telescope (HST) image reveals a pair of one-half light-year long interstellar "twisters" -- eerie funnels and twisted-rope structures -- in the heart of the Lagoon Nebula (Messier 8) which is 5,000 light-years away in the direction of the constellation Sagittarius. The Lagoon Nebula and nebulae in other galaxies are sites where new stars are being born from dusty molecular clouds.
The central hot O type star, Herschel 36 (lower right), is the primary source of the ionizing radiation for the brightest region in the nebula, called the Hourglass. Other hot stars in the nebula also are ionizing the extended optical nebulosity. The ionizing radiation induces photo-evaporation of the surfaces of the clouds and drives away violent stellar winds tearing into the cool clouds. Analogous to the spectacular phenomena of Earth tornadoes, the large difference in temperature between the hot surface and cold interior of the clouds, combined with the pressure of starlight, may produce strong horizontal shear to twist the clouds into their tornado-like appearance.
These color-coded images are the combination of individual exposures taken in July and September, 1995 with Hubble's Wide Field and Planetary Camera 2 (WFPC2) through three narrow-band filters (red light -- ionized sulfur atoms, blue light -- double ionized oxygen atoms, green light -- ionized hydrogen).
Image Title: Giant "Twisters" in the Lagoon Nebula
based on press release for PHOTO NO.: STScI-PRC96-38b
Credit: A. Caulet (ST-ECF, ESA), and NASA
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Last Modified On: Sunday, December 17, 2000