This false-color [
http://hubblesite.o…2004/30/ ] image of banded gas giant Jupiter shows a triple eclipse in progress on March 28 - a relatively rare [
http://antwrp.gsfc.…] event, even for a large planet with [
http://antwrp.gsfc.…] many moons. Captured by the Hubble Space Telescope's near-infrared camera are shadows of [
http://hubblesite.o…2004/30/image/b ] Jupiter's moons Ganymede (left edge), Callisto (right edge) and Io, three black spots crossing the sunlit Jovian cloud tops. In fact, Io itself [
http://antwrp.gsfc.…] is visible as [
http://hubblesite.o…2004/30/image/c ] a white spot near picture center with a bluish Ganymede above and to the right, but Callisto is off the right hand edge of the scene. Viewed from Jupiter's perspective, these shadow crossings [
http://antwrp.gsfc.…] would be seen as solar eclipses, analogous to the Moon's shadow [
http://antwrp.gsfc.…] crossing the sunlit face of planet Earth. Historically [
http://www.what-is-…early-thoughts-speed -of-light.html ], timing the eclipses of Jupiter's moons allowed astronomer Ole Roemer [
http://www.college-…museum/observatory/r oemer.htm ] to make the first accurate measurement [
http://www.what-is-…roemer-speed-of-ligh t.html ] of the speed of light in 1676.
Explanation
This false-color [
http://hubblesite.o…2004/30/ ] image of banded gas giant Jupiter shows a triple eclipse in progress on March 28 - a relatively rare [
http://antwrp.gsfc.…] event, even for a large planet with [
http://antwrp.gsfc.…] many moons. Captured by the Hubble Space Telescope's near-infrared camera are shadows of [
http://hubblesite.o…2004/30/image/b ] Jupiter's moons Ganymede (left edge), Callisto (right edge) and Io, three black spots crossing the sunlit Jovian cloud tops. In fact, Io itself [
http://antwrp.gsfc.…] is visible as [
http://hubblesite.o…2004/30/image/c ] a white spot near picture center with a bluish Ganymede above and to the right, but Callisto is off the right hand edge of the scene. Viewed from Jupiter's perspective, these shadow crossings [
http://antwrp.gsfc.…] would be seen as solar eclipses, analogous to the Moon's shadow [
http://antwrp.gsfc.…] crossing the sunlit face of planet Earth. Historically [
http://www.what-is-…early-thoughts-speed -of-light.html ], timing the eclipses of Jupiter's moons allowed astronomer Ole Roemer [
http://www.college-…museum/observatory/r oemer.htm ] to make the first accurate measurement [
http://www.what-is-…roemer-speed-of-ligh t.html ] of the speed of light in 1676.
Explanation
