Sun corona temperature photosphere heating mechanisms

The Sun’s corona is far hotter than its surface

1–2 million K

The corona, the Sun’s outer atmosphere, reaches 1,000,000–2,000,000 K, while the photosphere beneath it is about 6,000 K. Proposed ways to heat the corona include waves and magnetic reconnection, but the explanation remains unresolved.

Japan had widespread schooling before modernization

Before Japan's Meiji modernization, commoner education was already widespread. By the end of Tokugawa rule, more than 11,000 terakoya schools had 750,000 students. In the 1860s, an estimated 40–50% of boys and 15% of girls had some schooling outside the home—rates comparable to major European nations apart from Germany.

Europeans became shorter after cereal farming spread

After Europeans shifted toward cereal farming, average height fell from about 178 to 165 cm for men and from 168 to 155 cm for women. Average height did not return to earlier levels until the 20th century.

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Sun corona temperature photosphere heating mechanisms

The Sun’s corona is far hotter than its surface

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