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Solar Dynamics Observatory

The Solar Dynamics Observatory (SDO) is a NASA mission launched in 2010 to observe the Sun. It provides high-resolution images of the Sun's atmosphere, helping scientists understand solar variability and its impact on Earth.

Source: nasa.gov

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Equinox and the Iron Sun

23/09/2010

Equinox and the Iron Sun
Image Credit: NASA Astronomy Picture of the Day

Today, the Sun crosses the celestial equator heading south at 03:09 Universal Time. Known as an equinox, this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. Equinox means equal night. With the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. Of course, in the north the days continue to grow shorter, the Sun marching lower in the sky as winter approaches. To celebrate the equinox, consider this view of the Sun in extreme ultraviolet light from the Sun staring Solar Dynamics Observatory. Recorded yesterday, the false-color image shows emission from highly ionized iron atoms. Loops and arcs trace the glowing plasma suspended in magnetic fields above solar active regions.