Sun corona eclipse

The solar corona is the Sun's outermost atmosphere, visible to the naked eye only during a total solar eclipse, revealing multimillion-degree plasma.

About this subject

The solar corona is one of the most intriguing regions of the Sun. It extends millions of kilometers into space, but its temperature puzzles scientists: while the solar surface (photosphere) is about 5,500 degrees Celsius, the corona reaches 1 to 3 million degrees. This paradox, known as the coronal heating problem, remains incompletely explained. It is believed that magnetic fields and plasma waves transport energy from the surface to the corona, heating it to extreme temperatures.

During a total solar eclipse, the Moon blocks the photosphere's light, making the corona visible. This phenomenon lasts only a few minutes, at most 7 minutes and 30 seconds. Historically, total eclipses have been crucial for science: in 1919, Arthur Eddington used an eclipse to confirm Einstein's general theory of relativity by observing the bending of starlight near the Sun.

Currently, studying the solar corona is vital for understanding the solar wind and geomagnetic storms. Probes such as Parker Solar Probe and Solar Orbiter gather in-situ data, but total eclipses remain unique opportunities for high-resolution observations. The corona also reveals structures like plumes, loops, and coronal mass ejections, which can affect satellites and power grids on Earth.

Culturally, the solar corona has always fascinated humanity. In various mythologies, the Sun was seen as a god, and its obscuration during an eclipse caused fear. Today, the vision of a white ethereal corona around the Moon's dark disk is a spectacle that unites science and wonder, reminding us of the complexity and beauty of the universe.

Frequently Asked Questions

Why is the solar corona so hot?

The corona reaches millions of degrees while the solar surface is about 5500°C. The exact mechanism is still under research, but plasma waves and magnetic reconnection are thought to transport energy from the photosphere to the corona, heating it.

How long is the corona visible during an eclipse?

Only a few minutes, at most 7 minutes and 30 seconds, during the totality of a total solar eclipse.

Why is studying the solar corona important?

The corona is the source of the solar wind, which affects space weather. Understanding it helps predict geomagnetic storms that can disrupt satellites and power grids on Earth.