Cosmic mystery: how will the total eclipse of the Sun reveal the enigma of the corona?


An article recently published on The Conversation platform presents an important research activity that will be carried out during the total solar eclipse, which will occur in North American countries on April 8th. Taking advantage of the darkness provided by the Moon’s passage between the Sun and Earth, an international team of scientists will investigate the solar corona.

According to the article’s author, Huu Morgan, reader of physical sciences (specialist in solar physics) at Aberystwyth University in Wales, the idea is to take advantage of the momentary darkness produced by the Moon to “shed light on a long-standing enigma over the outermost part of the Sun’s atmosphere — its corona.”

The enigma concerns the brutal temperature difference between the solar corona, heated to up to 2 million degrees Celsius, and the visible surface of the Sun (photosphere) which is 5,500 degrees Celsius. If it is true that as we move away from a heat source, the temperature drops, then why is the solar corona so much more absurdly hot? Follow along!

Surfing through the solar eclipse

The path of visual totality of the solar eclipse, through Mexico, USA and Canada.Source: Image Source: NASA Scientific Visualization Studio

The great difficulty in researching the Earth’s solar corona is that, although we can observe it safely – because it is very thin – it is very dangerous to look directly at the surface of the Sun.

This is because, despite the distance of 150 million kilometers, the density of the photosphere allows its temperature to emit around 65 megawatts per square meter, enough to cause irreparable damage to human vision.

That’s why, Observing the solar corona during a solar eclipse is a much cheaper way than space probes or telescopes with coronagraphs. Therefore, the team that will conduct the experiments near Dallas, USA, will use two main scientific instruments:

  • Cip (coronal imaging polarimeter);
  • Chils (high resolution coronal line spectrometer).

How do scientific instruments work during the eclipse?

It is not safe to observe partial phases of the eclipse without adequate sun protection!Source: Image Source: Getty Images

The Cip works as a filter for the corona light, composed of waves that vibrate in a single geometric plane, for an “aligned” shape. allowing only one specific polarization type to pass. This will allow the measurement of fundamental properties of the corona, such as its density.

The instrument will also help identify sources of solar wind currents, a stream of superheated particles in the form of plasma continually expelled from the Sun, in addition to the fearsome coronal mass ejections into space.

Chils collects high-resolution spectra, where the component colors of light can reveal a spectral signature of iron emitted by the corona, to map its surface. The resulting models could explain how coronal plasma manages to reach such high temperatures,

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The article is in Portuguese

Tags: Cosmic mystery total eclipse Sun reveal enigma corona



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