The Sun
Sun is the largest object in our solar system and contains approximately 98% of the total solar system mass.
It is 92.95 × 106 miles away from us (149.6 × 106 km) .
It has a diameter of 864,950 miles (1.392 million km.)
the amount of solar energy that reaches us is equal to 10,000 times the annual global energy consumption. On average, 1,700 kWh per square meter every year.
How does the sun work?
One of solar energy facts is that the sun is effectively a massive nuclear reactor. When you consider that we have such an incredibly huge nuclear reactor in the neighborhood already, it seems ridiculous that some folks want to build more!
The sun is constantly converting hydrogen to helium, minute by minute, second by second.
But what stops the sun from exploding in a massive thermonuclear explosion?—simple gravity! The sun is caught in a constant struggle between wanting to expand outwards as a result of the energy of all the complex reactions occurring inside it, and the massive amount of gravity as a result of its enormous amount of matter, which wants to pull everything together. All of the atoms inside the sun are attracted to each other, this produces a massive compression which is trying to “squeeze” the sun inwards.
Meanwhile, the energy generated by the nuclear reactions taking place is giving out heat and energy which wants to push everything outwards. Luckily for us, the two sets of forces balance out, so the sun stays constant!
Structure of the sun.
Figure below illustrates the structure of the sun—now let’s explain what some of those long words mean! Starting from the center of the sun we have the core, the radiative zone, the convective zone, the photosphere, the chromosphere, and the corona.
The core
The core of the sun possesses two properties which create the right climate for nuclear fusion to occur—the first is incredibly high temperature 15 million degrees Celsius (I don’t envy the poor chap who had to stand there with a thermometer to take the reading) and the second is incredibly high pressure. As a result of this nuclear fusion takes place. In nuclear fusion, you take a handful of hydrogen nuclei—four in fact, smash them together and end up with one helium nucleus. There are two products of this process—gamma rays which are high-energy photons and neutrinos, one of the least understood particles in the universe, which possess no charge and almost no mass.
The radiative zone
Next out from the core is the radiative zone. This zone is so named because it is the zone that emits radiation. A little bit cooler, the temperature in the radiative zone ranges from 15 million to 1 million degrees Celsius (even at that temperature though, I still wouldn’t have liked to have been the one holding the thermometer).
What is particularly interesting about the radiative zone, is that it can take millions of years for a photon to pass through this zone to get to the next zone, aptly named the convective zone!
The convective zone
This zone is different, in that the photons now travel via a process of convection—if you remember high school physics, you will recollect that convection is a process whereby a body makes its way to a region of lower temperature and lower pressure. The boundary of this zone with the radiative zone is of the order of a million degrees Celsius; however, toward the outside, the temperature is only a mere 6,000°C (you still wouldn’t want to hold the thermometer even with asbestos gloves)
The photosphereThe next region is called the photosphere. This is the bit that we see, because this is the bit that produces visible light. Its temperature is around 5,500°C which is still mighty hot. This layer, although relatively thin in sun terms is still around 300 miles thick.
The chromosphere.Sounding like a dodgy nightclub, the chromosphere is a few thousand miles thick, and the temperature rises in this region from 6,000°C to anywhere up to 50,000°C. This area is full of excited hydrogen atoms, which emit light toward the red wavelengths of the visible spectrum.
The coronaThe corona, which stretches for millions of miles out into space, is the outer layer of the sun’s atmosphere. The temperatures here get mighty hot, in fact up to a million degrees Celsius. Some of the features on the surface of the sun can be seen in Figure below.
Features of the sun
Now we might like to take a look at what goes on the surface of the sun, and also outside it in the immediate coronal region.( Take a look at the upper figure )
Coronal holes form where the sun’s magnetic field lies. Solar flares, also known as solar prominences, are large ejections of coronal material into space. Magnetic loops suspend the material from these prominences in space. Polar plumes are altogether smaller, thinner streamers that emanate from the sun’s surface.
After all of this don’t you think that we can depend on solar energy as a main source of our energy consumption and don’t you believe that Earth is a solar city !
It is 92.95 × 106 miles away from us (149.6 × 106 km) .
It has a diameter of 864,950 miles (1.392 million km.)
the amount of solar energy that reaches us is equal to 10,000 times the annual global energy consumption. On average, 1,700 kWh per square meter every year.
How does the sun work?
One of solar energy facts is that the sun is effectively a massive nuclear reactor. When you consider that we have such an incredibly huge nuclear reactor in the neighborhood already, it seems ridiculous that some folks want to build more!
The sun is constantly converting hydrogen to helium, minute by minute, second by second.
But what stops the sun from exploding in a massive thermonuclear explosion?—simple gravity! The sun is caught in a constant struggle between wanting to expand outwards as a result of the energy of all the complex reactions occurring inside it, and the massive amount of gravity as a result of its enormous amount of matter, which wants to pull everything together. All of the atoms inside the sun are attracted to each other, this produces a massive compression which is trying to “squeeze” the sun inwards.
Meanwhile, the energy generated by the nuclear reactions taking place is giving out heat and energy which wants to push everything outwards. Luckily for us, the two sets of forces balance out, so the sun stays constant!
Structure of the sun.
Figure below illustrates the structure of the sun—now let’s explain what some of those long words mean! Starting from the center of the sun we have the core, the radiative zone, the convective zone, the photosphere, the chromosphere, and the corona.
The core
The core of the sun possesses two properties which create the right climate for nuclear fusion to occur—the first is incredibly high temperature 15 million degrees Celsius (I don’t envy the poor chap who had to stand there with a thermometer to take the reading) and the second is incredibly high pressure. As a result of this nuclear fusion takes place. In nuclear fusion, you take a handful of hydrogen nuclei—four in fact, smash them together and end up with one helium nucleus. There are two products of this process—gamma rays which are high-energy photons and neutrinos, one of the least understood particles in the universe, which possess no charge and almost no mass.
The radiative zone
Next out from the core is the radiative zone. This zone is so named because it is the zone that emits radiation. A little bit cooler, the temperature in the radiative zone ranges from 15 million to 1 million degrees Celsius (even at that temperature though, I still wouldn’t have liked to have been the one holding the thermometer).
What is particularly interesting about the radiative zone, is that it can take millions of years for a photon to pass through this zone to get to the next zone, aptly named the convective zone!
The convective zone
This zone is different, in that the photons now travel via a process of convection—if you remember high school physics, you will recollect that convection is a process whereby a body makes its way to a region of lower temperature and lower pressure. The boundary of this zone with the radiative zone is of the order of a million degrees Celsius; however, toward the outside, the temperature is only a mere 6,000°C (you still wouldn’t want to hold the thermometer even with asbestos gloves)
The photosphereThe next region is called the photosphere. This is the bit that we see, because this is the bit that produces visible light. Its temperature is around 5,500°C which is still mighty hot. This layer, although relatively thin in sun terms is still around 300 miles thick.
The chromosphere.Sounding like a dodgy nightclub, the chromosphere is a few thousand miles thick, and the temperature rises in this region from 6,000°C to anywhere up to 50,000°C. This area is full of excited hydrogen atoms, which emit light toward the red wavelengths of the visible spectrum.
The coronaThe corona, which stretches for millions of miles out into space, is the outer layer of the sun’s atmosphere. The temperatures here get mighty hot, in fact up to a million degrees Celsius. Some of the features on the surface of the sun can be seen in Figure below.
Features of the sun
Now we might like to take a look at what goes on the surface of the sun, and also outside it in the immediate coronal region.( Take a look at the upper figure )
Coronal holes form where the sun’s magnetic field lies. Solar flares, also known as solar prominences, are large ejections of coronal material into space. Magnetic loops suspend the material from these prominences in space. Polar plumes are altogether smaller, thinner streamers that emanate from the sun’s surface.
After all of this don’t you think that we can depend on solar energy as a main source of our energy consumption and don’t you believe that Earth is a solar city !
ReplyDeleteGreat job! Very informative blog.Hope that you will continue to do posting...properties