STAFF REPORT

On April 8, a unique opportunity to witness the sun’s Corona—the hottest object ever seen by human eyes—will present itself to those who are inside a constrained route via Mexico, the United States, and eastern Canada.

Corona, which means “crown,” is what is visible during an eclipse and appears like streaming plasma leaving the sun in fascinating patterns.

Once the sun’s dazzling surface is completely hidden, it is safe to stare into this outer atmosphere, which shines with an odd white light. However, without appropriate eye protection, like a shadow box or an authorized filter, it is unsafe to view partial phases of the eclipse.

Without realizing it, humanity has been in awe of this spectacle for a very long time. It is currently known to astronomers that the sun’s Corona may reach temperatures of up to 2 million degrees Kelvin, which is roughly equivalent to a temperature of 2 million degrees Celsius.

The reason behind the Corona’s extreme heat is still a mystery to astronomers.

DENSITY AND HEAT
Merely 5,800 kelvins, or 9,900 degrees Fahrenheit, or 5,500 degrees Celsius, make up the surface of the sun. Density is the reason we can safely stare at the Corona but must look away from the surface: The majority of the light that we perceive is reflected sunlight from the surface, and the Corona is extremely thin.

The surface of the sun is dense enough to emit roughly 65 megawatts per square meter at its temperature. This is sufficient, even diluted by 150 million kilometers away from the sun, to inflict eye injury.

Despite its tremendous temperature, the Corona does not emit or reflect much light since it is such a thin gas. Because of this, we can only see it when the moon totally obscures the sun’s body. If not, our atmosphere’s dispersed light totally overwhelms it.

Astronomers in the 19th century were perplexed by the heat riddle of the Corona. New tools had been created at the time to investigate the makeup of celestial bodies.

Sir Issac Newton reported his findings in Opticks in 1704, showing that “white” light could be divided into many colors. Sadly, his fundamental misconceptions about light probably caused optical research to regress by a century!

Instruments were not produced until the early 1800s, which laid the groundwork for the tremendously lucrative German optical sector. This made it possible for scientists to identify materials by the light that they released when heated.

A mainstay of these investigations was the Bunsen burner, which was created without color at first like other flames.

PHOTOGRAPHY AND ASTROPHYSICS

In the meantime of invention of the photographic equipment the study of the astronomy was going through the transformation turning into astrophysics, and the sun has been recognized the first aim of the early apparatus due to its immense brightness.

At that time, not only the spectra of all the elements that had been studied before were confirmed but also some new emissions, like the bright red that was known to be from hydrogen, were observed. And it was this, when a spectroscope was used to divide a person on Earth, that they also saw a yellow light that they had never seen as such.

Its being called to be the new element was due to the fact that it was named just because of its relation to the sun (Greek helios). Only in 1895 was helium found on Earth, and in the strangest of places: radioactive mines.

Nearly all the helium that is used on Earth presently was extracted in a similar way from natural gas fields, where it had supposedly been dissolved alongside uranium and other dying radioactive substances. In the case of the helium in sun, it later made strong data for the Big Bang. That is, the first nucleus (hydrogen) quickly became the basis for nuclear fusion, but, its detection in the sun presaged some new elements’ production there.

A NEW MYSTERY

In 1800, when spectroscopy was in the beginning, a new trouble was found out. Russian chemist Dmitri Mendeleev did a huge work by which he discovered the elements existing on the Earth and also the classification system to group them into the “periodic table.”

While the phenomenon was registered throughout the observations, the spectral lines content could only be established by means of measuring how much of radiation coming from different solar layers got absorbed by them, leaving only dark and deep absorption features of varying heights. Despite the fact that gravity is unusual and mysterious, it ranks as one of the most fundamental forces in the universe. The fact that sun is mostly made of hydrogen and helium does not mean that these elements will dominate its spectrum.

Besides, the Corona was where an unknown for the people phenomenon was discovered. The emergence of helium on the Earth as a result of leaking pressurised air balloon is intriguing for scientists who decide that most likely that Sun is a container of the hitherto unknown element to be crowned with the name of coronium. It wasn’t until the 1940s, that scientists finally knew that the emissions were released from the elements such as iron, which was the most notable of all. This was not initially common since the spectrum showed high levels of ionization, that is, to get the complete stripping of the nucleus one needed to carry out the action at quite extremely high temperatures.

They could be puzzling because even though the Corona is farther away from the sun, it is hotter there in the Corona.

SOLAR WINDS AND WEATHER

In the late 1950s, the physicist Eugene Parker found that such high temperatures for the solar Corona meant that it could not be static; thus, it was going into outer space rather than coming down to Earth. This assumption turned out to be true, when Soviet spacecraft traveled the route to space and returned data in 1959.

From then until now, we have been aware that the solar wind exists and that the magnetic field revealed as a part of corona material is carried off by sun wind. The solar wind can deliver energy to our planet, which is most noticeable when the Earth’s magnetic field is low and our magnetosphere is penetrated by the solar material. This bring radiant displays known as the Southern Lights.

Parker Solar Probe from NASA is now approaching abode of the inner Corona, the aim of which is the exact point where the solar wind begins. Parker, who passed away in 2022, got the first information from this spacecraft about some details of the mass of the exorbitantly hot Corona of the Sun which provides the solar wind.

On the other hand, the eclipse on April 8 should be considered as a very unique chance to gaze even closer at the Sun’s unbelievably hot Corona without risking our eyes to any hazard.