Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. A wind from the Sun blows through our Solar System . The behaviour of comet tails as they flapped and waved in this interplanetary breeze gave astronomers the first hint of its existence. Rooted in the Solar Magnetic Field , the structure of the corona is visible extending a million miles above the Sun's surface in this composite image from the EIT and UVCS instruments onboard the SOHO spacecraft . The dark areas, known as coronal holes, represent the regions where the highest speed Solar Wind originates.
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