Photo #1 (October 2007)

THE COLORFUL CLOUDS OF RHO OPHIUCHI 

Center of all centers, core of cores,
almond self-enclosed and growing sweet-
all this universe, to the furthest stars
and beyond them is your flesh, your fruit.

Now you feel how nothing clings to you;
Your vast shell reaches into endless space,
And there the rich, thick fluids rise and flow.
Illuminated in your infinite peace,

A billion stars go spinning through the night,
blazing high above your head.
But in you is the presence that
will be, when all the stars are dead."
                - Rainer Maria Rilke

The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the star Rho Ophiuchi and nearby stars reflects more efficiently off this portion of the nebula than red light. The Earth's daytime sky appears blue for the same reason. The red and yellow regions shine primarily because of emission from the nebula's atomic and molecular gas. Light from nearby blue stars - more energetic than the bright star Antares - knocks electrons away from the gas, which then shines when the electrons recombine with the gas. The dark regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them. The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible above on far lower left, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray.