Malina (the sun-goddess of the Eskimo people) and her brother Anningan (the moon-god of the Eskimo people) got into a fight one day; Malina spread black grease all over Anningan’s face. Malina ran away as far as she could into the sky, and Anningan chased after her; to this day he is still chasing his sister thus conceived day and night. This is how the Eskimo’s believe that the sun was created; since the beginning of time, human beings have pondered the existence of the sun, and each ancient society had its own stories of sun gods. In the twenty-first century we have determined that the sun is a great fiery mass that was created approximately 5 billion years ago. From the sun’s inner core to its outer corona rays, the sun is a magnificent ball of gas that radiates across our vast solar system; whether it be the suns soaring prominences or its immense size, the sun has awed astronomers and fueled their studies and exploration.
For astronomers, studying the sun was always difficult because looking directly into the sun would damage one’s eyes. In 384 BC, Greek philosopher Aristotle created the first known obscura, he placed a hole in a screen that allowed the image of the sun on the ground; we use this device today to observe solar eclipses. In 1610 Italian scientist Galileo observed the sun through a telescope that he had created with a screen behind the eye piece, this protected his eyes; he observed sunspots move and change shape and proved that the sun was an active body. More recently in the nineteenth century, after nuclear fusion had been discovered scientists determined the source of the suns energy. Finally scientists began studying the sun from space which led too a jump in solar astronomy some missions include: Sputnik 2 in 1957 from the Soviet Union and the Pioneer of the United States in 1950.
The sun is comprised of six layers: the core, the radiation zone, the convection zone, the photosphere, the chromosphere, and the corona. The core is where all of the energy from the sun is produced; the core of the sun is measured to be approximately 15 million Kelvin. To create this kind of energy, many stars use nuclear fusion; in this process two light hydrogen protons fuse together to create a heavy helium nucleus. Our sun, like other small stars its size use the proton-proton chain in which four hydrogen nuclei fuse into one helium nucleus. The next layer is the radiation zone; here gamma rays from the core scatter, particles in the radiation zone continuously radiate and deflect photons of energy. A photon transferring energy from the core to the convective zone stays in the radiative zone sometimes an average of 170,000 years due to its repeated bouncing in the radiative zone. In the convective zone, the temperature has significantly dropped to about 2.2 million Kelvin; the gases in the convective zone circulate hot gases to the top of the convection zone and push cooler gases down to the bottom, it takes particles about ten days to go through the convective zone. Next is the photosphere, this is the sun’s visible surface; it is approximately 5800 Kelvin and less than 500 kilometers deep and is where Earth gets most of its sun light from; here also are sunspots visible from Earth, these are cool spots in the photosphere that are directly linked to the sun’s magnetic fields. The final two layers are the chromosphere and the corona, these layers are about 1000 times fainter than the photosphere and can be seen with the unaided eye during a solar eclipse; they give off a pink glow on the outline of the moon. The gas of the chromoshpere and the corona create huge bursts of energy that loop around from inside the photosphere out through to the surface of the corona called prominences; prominences make the corona the hottest layer of the sun’s atmospheres.
A unique feat of the sun, prominences are produced by the suns magnetic fields. Like the Earth the sun rotates around an axis, but being a ball of gas it doesn’t rotate as a solid body of mass; the equator of the sun makes one rotation of the sun, whereas at 45 degrees latitude is about twenty eight days; this phenomenon is called differential rotation; it is the key factor in the suns magnetic cycle. With the magnetic pull of the sun when ionized gas shoots up out of the corona; it creates an arch sometimes larger in diameter than the Earth. Another awesome occurrence of the sun is solar winds, when ionized gases from inside the sun escape from coronal holes without looping back into a prominence it blows toward the Earth, sometimes creating beautiful solar auroras in the Earth’s upper atmosphere.
What does the future hold for the sun? Astronomers approximate the sun has about eight billion more years till it becomes nothing more than a white dwarf; it will continue using up its hydrogen until it is exhausted. The timeline says that in three billion years the suns temperature will continue rising so that it doesn’t collapse on itself and it will be hot enough to evaporate all of the Earth’s oceans away; then in four billion years the sun will have drained all of its hydrogen and will turn into a giant star and absorb the planet Mercury; after this the sun will become a red giant star and 2,000 times brighter than it is currently. It will be so large and close that it will melt the rocks on Earth, and planets that were farther from the sun will now have the heat of the sun to sustain life; the giant planets that were once ice would now be planets covered by water. Eventually the red giant sun will run out of helium and no longer be able to support the layers of the sun causing it to become a white dwarf; in the final billion years, the sun will gradually cool down until it is no longer able to produce light.
I feel that the sun is a magnificent star, my favorite star; it gives the Earth light, it is the force behind spring, summer, fall, and winter. Surely astronomers still have not found everything there is to know about the sun, and I hope I am alive when these discoveries are made. All in all, I feel that the theory of the sun slowly running out of helium and scorching the Earth’s surface is a scary thought, but I am also intrigued at the thought that in seven billion years other planets in our solar system could sustain life.
- Seeds, Michael A. Foundations of Astronomy Ninth Edition. California: Brooks/Cole, 2005.
- “Sun.” Microsoft® Encarta® Online Encyclopedia 2008. 11 Nov. 2008 .
- Golub, Leon L. Nearest Star: the suprising science of our sun. Cambridge, MA: Harvard UP, 2001.