Summary

Original Caption Released with Image:
VOLCANIC EXPLOSION ON IO: Voyager 1 acquired this image of Io on March 4 at 5:30 p.m. (PST) about 11 hours before closest approach to the Jupiter moon. The distance to Io was about 490,000 kilometers (304,000 miles). An enormous volcanic explosion can be seen silhouetted against dark space over Io's bright limb. The brightness of the plume has been increased by the computer as it is normally extremely faint, whereas the relative color of the plume (greenish white) has been preserved. At this time solid material had been thrown up to an altitude of about 100 miles. This requires an ejection velocity from the volcanic vent of about 1200 miles per hour, material reaching the crest of the fountain in several minutes. The vent area is a complex circular structure consisting of a bright ring about 300 kilometers in diameter and a central region of irregular dark and light patterns. Volcanic explosions similar to this occur on the Earth when magmatic gases expand explosively as material is vented. On Earth water is the major gas driving the explosion. Because Io is thought to be extremely dry, scientists are searching for other gases to explain the explosion. JPL manages and controls the Voyager Project for NASA's Office of Space Science.

source:http://photojournal.jpl.nasa.gov/catalog/?IDNumber=PIA01971

TIFF verion:http://photojournal.jpl.nasa.gov/tiff/PIA01971.tif

This image or video was catalogued by Jet Propulsion Laboratory of the United States National Aeronautics and Space Administration (NASA) under Photo ID: PIA01971. This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing. Other languages: العربية ∙ беларуская (тарашкевіца) ∙ български ∙ català ∙ čeština ∙ dansk ∙ Deutsch ∙ English ∙ español ∙ فارسی ∙ français ∙ galego ∙ magyar ∙ հայերեն ∙ Bahasa Indonesia ∙ italiano ∙ 日本語 ∙ македонски ∙ മലയാളം ∙ Nederlands ∙ polski ∙ português ∙ русский ∙ sicilianu ∙ slovenščina ∙ Türkçe ∙ українська ∙ 简体中文 ∙ 繁體中文 ∙ +/−

Licensing

	This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.)
	Warnings: Use of NASA logos, insignia and emblems is restricted per U.S. law 14 CFR 1221. The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain. Materials based on Hubble Space Telescope data may be copyrighted if they are not explicitly produced by the STScI.[1] See also {{PD-Hubble}} and {{Cc-Hubble}}. The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2] Images featured on the Astronomy Picture of the Day (APOD) web site may be copyrighted. [3] The National Space Science Data Center (NSSDC) site has been known to host copyrighted content. Its photo gallery FAQ states that all of the images in the photo gallery are in the public domain "Unless otherwise noted."