The Solar Corona is a plasma from which solar wind originates and X-rays are emitted. Appearing as a halo around the sun, it extends over a million km from the surface of the Sun and is visible to us only during a solar eclipse when the moon blocks the main radiation from the Sun’s surface. The “Solar Corona Problem” comes about because, while the temperature of Sun’s core measures 15 million degrees, the Sun’s surface registers at only 5000 degrees and the temperature would be expected to far lower farther away from the surface. Instead, the mechanism of heating the Solar Corona to an incredible 1 million degrees has puzzled scientists for over 50 years. Many scientists believe it has to do with a magnetic field patches on the Sun but proof and refinement of this theory await further evidence.
The Hinode Mission carries with it three main scientific instruments to explore the Sun: a 0.5 m Solar Optical Telescope (SOT) in the visible range, an X-ray Telescope (XRT), which captured the image above and is used to study the corona’s hottest regions, and the Extreme-Ultraviolet Imaging Spectrograph (EIS) to identify the processes involved in coronal heating.
The Hinode, launched from the Uchinoura Space Center (USC) in Japan in September 2006, is the successor of Yohkoh (meaning sunbeam; a.k.a. Solar-A), which was launched in 1991 and operated until 2005 when it burned up during reentry over South Asia. Also known as Solar-B, the Hinode (Japanese for sunrise) is a joint program of Japan’s Aerospace Exploration Agency (JAXA), the US, and the UK.