1. Good Day Sunshine
Observing the Sun from space
Radio telescopes do not provide our only window on the invisible Sun. There are the invisible gamma-rays, X-rays, and ultraviolet radiation. They are all absorbed in our atmosphere and must be collected by telescopes in satellites that orbit the Earth above its atmosphere These space telescopes measure the intensity of the incoming signal and convert these measurements into radio transmissions that are sent to radio telescopes on the ground. Spacecraft can also directly sample the particles and magnetic fields flowing from the Sun.
Solar astronomy from space has several advantages over ground-based observations. The weather in space is always perfectly clear, and the images are not blurred by the atmosphere. Moreover, if the space telescope is placed in the right location, it can view the Sun 24 hours a day, every day, for years.
Seven modern spacecraft, Yohkoh, Ulysses, Wind, the Solar and Heliospheric Observatory, abbreviated SOHO, ACE, TRACE, RHESSI, Hinode, and STEREO, have recently made revolutionary discoveries about the Sun, (Fig 1.23, 1.24, 1.20). Major new instruments aboard these spacecraft have traced the flow of energy and matter from down inside our star to the Earth and beyond, providing insights that are vastly more focused and detailed than those of previous solar missions. Indeed, we may have obtained more essential new information about the Sun from these spacecraft than the entire previous century of investigations.
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Copyright 2010, Professor Kenneth R. Lang, Tufts University