The Sun
Our Sun is the largest object in our Solar System. It makes up 98% of all its matter. Since the Sun is so large compared to everything else, it is easily able to hold on to the rest of the matter, causing everything else to orbit around it. It has a magnitude (intrinsic brightness) of 4.83. It also classes as a Stellar type G. This is a star that absorbs strong metallic lines in its spectrum. It is composed of 75% hydrogen, 25% helium and 0.1% metals. This ratio is very slowly changing over time as the nuclear reactions continue converting smaller atoms into more massive ones. Our Sun is a second or third generation star. Second generation stars do not just burn hydrogen, they also burn heavier elements, like helium and metals.
There are 6 layers of the Sun which are chromosphere, photosphere, corona, radiative zone, convection zone and core. The innermost layer of the sun is the core. The core is the source of the Sun’s energy. It is the site of thermonuclear fusion, the core’s temperature is about 15 million °K and the matter is a state known as plasma. Plasma is the fourth state of matter; this is where the atoms are different because they are made up of free electrons.
Atomic nuclei (mainly protons) and electrons are moving at very high speeds. Under these conditions, two protons can collide together; they overcome their electrical repulsion and become cemented together by a strong nuclear force. The energy released from the core is in a form of gamma ray. Gama rays are photons with high energy and high frequency. The energy output of the Sun’s core is so large that it would shine 1013 times brighter than the solar surface.
Chromosphere
In an eclipse, a red circle around the outside of the sun can sometimes be seen. This is the chromosphere which can only be seen easily in a total solar eclipse. It is seen to be reddish in colour caused by the great amount of hydrogen. This colour is the origin of its name (chromos meaning colour). The chromosphere is 2000-3000 km thick and its temperature is about 7000 °K. The faint flow of the chromosphere is due to a diffusion spectrum from hot, low density gases emitting at individual wavelengths. The chromosphere contains spikes of gas called spicules that rise through it. Spicules are short-lived and move upward of about 30km per second and last only about 10 minutes.
Corona
The corona is the Sun’s outer atmosphere. It is the widest of all three regions of the Sun’s atmosphere and it extends for several million miles from the photosphere and chromosphere. At an average of 2 million degrees Kelvin, the corona is by far the hottest of the sun’s layers. Scientists are still unable to explain why it’s so hot. The corona is best seen in X-ray images and it is visible during total eclipses of the Sun as a pearly white crown surrounding the Sun. The corona displays a variety of features including streamers, plumes and loops. The corona also emits energy of many different wavelengths, from long wavelength radio waves, to short wavelength X-rays.
Radiative Zone
The radiative zone is a very important aspect of the Sun. It extends outward from the outer edge of the core to the interface layer at the base of the convection zone. It is the main process through with the Sun transfers its energy out into space. In radiation, energy diffuses out from the core through the photons. They move very quickly (at the speed of light), but they also bounce off so many other particles that it takes hundreds of thousands of years for them to get through the radiative zone. All of the bouncing off of other particles sends the photons flying off in all directions, instead of taking a straight path outward. This is called a random walk.
Convection Zone
The convection zone is the area that we consider to form the outer shell of the Sun. It extends from a depth of 200,000 km up to the visible surface of the Sun. The atoms in this layer of the Sun have electrons because the temperature is not hot enough to strip them away like it is in the core (15.6X 106 K as opposed to 2 million K). Atoms with electrons are able to absorb and discharge radiation, making this region more opaque, like a thick fog. In the convective zone, the energy is transferred much faster than it is in the radiative zone. This is because it is transferred through the process of convection. Hotter gas coming from the radiative zone expands and rises through the convective zone. It can do this because the convective zone is cooler than the radiative zone and therefore less dense. As the gas rises, it cools and begins to sink again. As it falls down to the top of the radiative zone, it heats up and starts to rise. This process repeats, creating convection currents and the visual effect of boiling on the Sun's surface.
Photosphere
The surface of the sun is called the photosphere. Its density is from one-millionth, to one ten millionth, as dense as water. The photosphere is 340 miles thick and its temperatures range from 5,500°C to 6,000°C. A number of features can be observed in the photosphere with a simple telescope. These features include the dark sunspots, the bright facular and granules.
There are 6 layers of the Sun which are chromosphere, photosphere, corona, radiative zone, convection zone and core. The innermost layer of the sun is the core. The core is the source of the Sun’s energy. It is the site of thermonuclear fusion, the core’s temperature is about 15 million °K and the matter is a state known as plasma. Plasma is the fourth state of matter; this is where the atoms are different because they are made up of free electrons.
Atomic nuclei (mainly protons) and electrons are moving at very high speeds. Under these conditions, two protons can collide together; they overcome their electrical repulsion and become cemented together by a strong nuclear force. The energy released from the core is in a form of gamma ray. Gama rays are photons with high energy and high frequency. The energy output of the Sun’s core is so large that it would shine 1013 times brighter than the solar surface.
Chromosphere
In an eclipse, a red circle around the outside of the sun can sometimes be seen. This is the chromosphere which can only be seen easily in a total solar eclipse. It is seen to be reddish in colour caused by the great amount of hydrogen. This colour is the origin of its name (chromos meaning colour). The chromosphere is 2000-3000 km thick and its temperature is about 7000 °K. The faint flow of the chromosphere is due to a diffusion spectrum from hot, low density gases emitting at individual wavelengths. The chromosphere contains spikes of gas called spicules that rise through it. Spicules are short-lived and move upward of about 30km per second and last only about 10 minutes.
Corona
The corona is the Sun’s outer atmosphere. It is the widest of all three regions of the Sun’s atmosphere and it extends for several million miles from the photosphere and chromosphere. At an average of 2 million degrees Kelvin, the corona is by far the hottest of the sun’s layers. Scientists are still unable to explain why it’s so hot. The corona is best seen in X-ray images and it is visible during total eclipses of the Sun as a pearly white crown surrounding the Sun. The corona displays a variety of features including streamers, plumes and loops. The corona also emits energy of many different wavelengths, from long wavelength radio waves, to short wavelength X-rays.
Radiative Zone
The radiative zone is a very important aspect of the Sun. It extends outward from the outer edge of the core to the interface layer at the base of the convection zone. It is the main process through with the Sun transfers its energy out into space. In radiation, energy diffuses out from the core through the photons. They move very quickly (at the speed of light), but they also bounce off so many other particles that it takes hundreds of thousands of years for them to get through the radiative zone. All of the bouncing off of other particles sends the photons flying off in all directions, instead of taking a straight path outward. This is called a random walk.
Convection Zone
The convection zone is the area that we consider to form the outer shell of the Sun. It extends from a depth of 200,000 km up to the visible surface of the Sun. The atoms in this layer of the Sun have electrons because the temperature is not hot enough to strip them away like it is in the core (15.6X 106 K as opposed to 2 million K). Atoms with electrons are able to absorb and discharge radiation, making this region more opaque, like a thick fog. In the convective zone, the energy is transferred much faster than it is in the radiative zone. This is because it is transferred through the process of convection. Hotter gas coming from the radiative zone expands and rises through the convective zone. It can do this because the convective zone is cooler than the radiative zone and therefore less dense. As the gas rises, it cools and begins to sink again. As it falls down to the top of the radiative zone, it heats up and starts to rise. This process repeats, creating convection currents and the visual effect of boiling on the Sun's surface.
Photosphere
The surface of the sun is called the photosphere. Its density is from one-millionth, to one ten millionth, as dense as water. The photosphere is 340 miles thick and its temperatures range from 5,500°C to 6,000°C. A number of features can be observed in the photosphere with a simple telescope. These features include the dark sunspots, the bright facular and granules.
Sun Spots, Flares, Prominences and Solar Winds
Sun spots, flares, prominences and solar winds are all features of the Sun.
Solar flare
A solar flare is an intense burst of radiation coming from the release of magnetic energy combined with sunspots. They are the bright areas on the sun and they can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, at most every wavelength of the spectrum. The primary ways we monitor flares are in X-rays and optical light. Flares are also sites where particles (electrons, protons, and heavier particles) are accelerated.
Solar flares can affect shortwave radio communication on earth. The orbit of earth satellites can also be altered by solar flares. People can be negatively be affected by them too, they may experience lots of tossing and turning in the night and some have unusual dreams.
Prominences
A solar prominence is a large, bright feature extending outward from the Sun's surface. Prominences are held to the Sun's surface in the photosphere, and extend outwards into the Sun's corona. A prominence forms over timescales of about a day, and balanced prominences may carry on in the corona for several months, looping hundreds of thousands of miles into space. Scientists are still researching how and why prominences are formed. An effect of prominences towards Earth is if a prominence breaks apart, it will produce a coronal mass ejection which is an ejection of hot plasma that may accelerate charged particles and travel as far as the Earth’s orbit and may create a magnetic storm on Earth.
Sun Spots
Sunspots are dark areas on the solar surface containing strong magnetic fields that are constantly shifting. A moderate-sized sunspot is about as large as the Earth. Sunspots form and expand over periods of days or weeks. They occur when strong magnetic fields arise through the solar surface and allow the area to cool slightly, from a background value of 6000 ° C down to about 4200 ° C; this area appears as a dark spot in difference with the very bright photosphere of the sun. The primary effect on the Earth of sun spots is on our ionosphere. This is the very upper part of the atmosphere; sunspot activity frequently accompanies an increase in the outflow of matter from the Sun in the form of a "solar wind". Charged particles in this wind can interact with atoms in the upper atmosphere and sometimes wreak havoc with our communications systems. It can interfere with the operation of satellites introducing background static. During periods of heightened solar activity, the Earth's upper atmosphere swells up slightly in response to the extra heating, which in turn increases the rate of decay of satellites in low Earth orbit.
Solar winds
Solar wind is the plasma of charged particles (protons, electrons, and heavier ionized atoms) coming out of the Sun in all directions at very high speeds -an average of about 400 km per second. Solar wind can affect the flight paths of spacecrafts. The solar wind varies usually through the 27-day rotation of the Sun, as well as infrequently, in response to violent eruptions in the corona. These eruptions can result in geomagnetic storms on Earth. These storms may affect Earths electronics.
Solar flare
A solar flare is an intense burst of radiation coming from the release of magnetic energy combined with sunspots. They are the bright areas on the sun and they can last from minutes to hours. We typically see a solar flare by the photons (or light) it releases, at most every wavelength of the spectrum. The primary ways we monitor flares are in X-rays and optical light. Flares are also sites where particles (electrons, protons, and heavier particles) are accelerated.
Solar flares can affect shortwave radio communication on earth. The orbit of earth satellites can also be altered by solar flares. People can be negatively be affected by them too, they may experience lots of tossing and turning in the night and some have unusual dreams.
Prominences
A solar prominence is a large, bright feature extending outward from the Sun's surface. Prominences are held to the Sun's surface in the photosphere, and extend outwards into the Sun's corona. A prominence forms over timescales of about a day, and balanced prominences may carry on in the corona for several months, looping hundreds of thousands of miles into space. Scientists are still researching how and why prominences are formed. An effect of prominences towards Earth is if a prominence breaks apart, it will produce a coronal mass ejection which is an ejection of hot plasma that may accelerate charged particles and travel as far as the Earth’s orbit and may create a magnetic storm on Earth.
Sun Spots
Sunspots are dark areas on the solar surface containing strong magnetic fields that are constantly shifting. A moderate-sized sunspot is about as large as the Earth. Sunspots form and expand over periods of days or weeks. They occur when strong magnetic fields arise through the solar surface and allow the area to cool slightly, from a background value of 6000 ° C down to about 4200 ° C; this area appears as a dark spot in difference with the very bright photosphere of the sun. The primary effect on the Earth of sun spots is on our ionosphere. This is the very upper part of the atmosphere; sunspot activity frequently accompanies an increase in the outflow of matter from the Sun in the form of a "solar wind". Charged particles in this wind can interact with atoms in the upper atmosphere and sometimes wreak havoc with our communications systems. It can interfere with the operation of satellites introducing background static. During periods of heightened solar activity, the Earth's upper atmosphere swells up slightly in response to the extra heating, which in turn increases the rate of decay of satellites in low Earth orbit.
Solar winds
Solar wind is the plasma of charged particles (protons, electrons, and heavier ionized atoms) coming out of the Sun in all directions at very high speeds -an average of about 400 km per second. Solar wind can affect the flight paths of spacecrafts. The solar wind varies usually through the 27-day rotation of the Sun, as well as infrequently, in response to violent eruptions in the corona. These eruptions can result in geomagnetic storms on Earth. These storms may affect Earths electronics.
Solar Cycle - Diagram
Here is a diagram the number of sunspots found each year from 1957 - 2011.
UV Radiation
UV radiation is part of the electromagnetic (light) spectrum and reaches the earth from the sun. It has wavelengths shorter than visible light, making it invisible to the naked eye. These wavelengths are classified as UVA, UVB or UVC. UVA is the longest of the three at 320-400 nanometers (nanometers meaning billionths of a meter). UVA is divided into two wave ranges, UVA l which measures 340-400 nanometers and UV ll which extends from 320-400 nanometers. UVB ranges from 290 to 320 nanometers and with even shorter rays most UVC is absorbed by the ozone layer and doesn’t reach the Earth.
UVA
Most of us are exposed to large amounts of UVA throughout our lifetime. UVA rays are present with relatively equal intensity during all daylight hours throughout the year, and can go through clouds and glass. UVA, which enters the skin more deeply then UVB, has always been known to play a major part in skin aging and wrinkling.
UVB
UVB, the cause of skin reddening and sunburn, tends to damage the skin’s more surface epidermal layers. It plays a key role in the development of skin cancer. Its intensity varies by season, location and time of day but it can burn and damage your skin all year round.
UVC
UVC rays cover the biggest part of UV radiations. They are the most dangerous of all the rays. UVC rays have the shortest wavelength, the most energy and fortunately do not come through the atmosphere as they are absorbed by the ozone layer.
UVA
Most of us are exposed to large amounts of UVA throughout our lifetime. UVA rays are present with relatively equal intensity during all daylight hours throughout the year, and can go through clouds and glass. UVA, which enters the skin more deeply then UVB, has always been known to play a major part in skin aging and wrinkling.
UVB
UVB, the cause of skin reddening and sunburn, tends to damage the skin’s more surface epidermal layers. It plays a key role in the development of skin cancer. Its intensity varies by season, location and time of day but it can burn and damage your skin all year round.
UVC
UVC rays cover the biggest part of UV radiations. They are the most dangerous of all the rays. UVC rays have the shortest wavelength, the most energy and fortunately do not come through the atmosphere as they are absorbed by the ozone layer.
Sunscreen Debate
Sunscreens come in two different categories:
However, most medial companies have concluded that sunscreen use is still beneficial.
- Chemical which work by absorbing the Sun’s rays and contain ingredients like Paba.
- Physical which work by reflecting the Sun’s rays and contain the minerals, zinc oxide and titanium dioxide.
- Some sunscreens only protect against UVB radiation and not against the more dangerous UVA radiation.
- Some sunscreen ingredients may be possibly deadly or have other health risks.
- Reduced exposure to UV light in sunlight can contribute to a lack of Vitamin D.
However, most medial companies have concluded that sunscreen use is still beneficial.