THe sun
Despite being the largest object in our solar system, the sun is only classified as a medium star with a life span of approximately 10 billion years. Of this, about half our sun's life has already passed by (approx. almost 5 billion years). As time passes the sun gets brighter. This is caused from the 700 million tonnes of hydrogen that is converted to 700 million tonnes of helium every second. With this per second transfusion, 5 million tonnes of energy is released, creating the sun's light and heat. This nuclear reaction is called fusion. 7.8% of the number of atoms in the Sun are helium which equals out to about 25% of its mass. 92.1% of atoms in the Sun is hydrogen, making up around 75% of its mass, The other 0.1% of atoms are the heavier elements such as, carbon, nitrogen, iron, oxygen, neon, magnesium and silicon.
Although it is only a medium star, the sun makes up around 98% of our solar system's mass. It is able to fit 1.3 million Earths in its interior and 110 across. 109 Earths can fit across the Sun's disk, which adds up to about 1.4 million kilometres. The sun is neither a solid nor gas but a substance called plasma. Plasma is a tenuous and gaseous substance. It is thinner on the outer layers of the Sun but becomes more dense towards the core.
Layers:
Similar to the Earth, the Sun is divided into layers. However, the Sun's layers are just a few thousand or million degrees hotter. The first of the Sun's layers is the core, coming up to approximately 15 000 000°C. It is in this section of the sun that fusion of hydrogen to helium takes place, providing the Sun with its light, heat and energy. Second is the radiative or radiation zone which is used as an efficient means of transferring heat and energy (radiation) from the core to the outer regions, but first it must pass through the next layer called the convective zone. The convective zone is the next stage of transferring this energy, however, the convective zone is much cooler than the radiative zone so energy has to be transferred in a different way. The bottom of the convective zone is much hotter (200 000°C) than its upper part (only about 5 700°C). This is due to the radiation which causes an effect much like boiling water. The 'boiling' effect is the cells in the plasma being in a state of turbulence. Since hot substances are lighter that cool substances, radiation and energy is carried up to the upper layers inside individual bubbles of hot plasma. When it reaches the top, some of the radiation and heat is released and becomes part of the photosphere. The continuous bubbling from the convective zone can be seen on the photosphere, this is called granulation. The photosphere is the part of the Sun visible to the naked eye or the visible surface (although no person should look at the Sun without some sort of eye protection), it is the layer of the Sun where light is emitted. From the core to the photosphere the temperature drops to only about 6000°C from the initial 15 million°C. It is on this layer that sun spots are found. Just above the photosphere is the chromosphere. The chromosphere a region of the Sun that usually can not be seen due to the fact that the light from the photosphere overpowers it. However, during the total point of a solar eclipse, it appears to look like a red ring surrounding the Sun with an irregular outer edge. The red colour of the chromosphere can also be seen in prominences when they project from the Sun. It is approximately 2 500km deep and is the layer where prominences and solar flares take place. It is also the region where spicules occur and spread into the corona lasting about 15 minutes. Spicules are jets of plasma shooting up from super granule boundaries. The corona is the last layer of the Sun. It extends further than one million kilometres out from the Sun's surface and can be more than a million degrees. That is the puzzling fact about the corona, despite the fact that the Sun cools dramatically from the core to the photosphere, the corona, which in theory should be cooler than the photosphere is approximately over 1 million degrees. Scientists have hypothesised that the reason for the corona's heat is to do with the magnetic fields covering the Sun. The corona also emits strong electromagnetic X-rays.
Magnetic fields:
The magnetic fields of the Sun are generated from its interior out to the solar system through the solar wind. Since the Sun is rotating, it winds up this magnetic field to form a spiral named the Parker spiral (after the scientist who described it). However, since the Sun is made of plasma, the gaseous sphere rotates faster at the equator than at its poles. Therefore each hemisphere projects the Parker spiral in opposite directions, one moving outwards and one moving inwards. Every 11 years, the magnetic fields of the Sun flip (magnetic north pole becomes south pole and vice versa). The magnetic fields of the Sun can be described as 'ropes' with one end coming out making an arch and diving back into the photosphere. The contrasting rotations of the Sun, as mentioned, are believed to be the cause of the Sun's magnetic fields. Due to the faster and slower rotations at the poles and equator, the overall magnetic field becomes distorted and twisted and this eventually reaches the surface. These 'ropes' and the twisted field lines can be seen through sunspots.
Sun Spots:
Sunspots are the darker regions visible on the surface of the Sun. They are believed to be cooler 'spots' on the Sun than the rest of the photosphere. In fact, sun spots only appear to be dark since the other parts of the Sun are so bright. If you took a sun spot and placed it in space, it would be as bright as a full moon during the night. Some of these sunspots can even be planet sized. Sunspots, as mentioned in the previous paragraph, are formed through the movement of magnetic fields. The points where the magnetic north and south poles of the 'ropes' meet the photosphere are where sunspots are located. Due to there being two poles for each 'rope', sunspots usually come in pairs meaning that one sunspot has north polarity and the other has south polarity. Sunspots move across the surface of the Sun and change their whereabouts yearly. However, scientists have been able to determine that there is a type of cycle which the sunspots appear. This is called the sunspot cycle and occurs approximately every 11 years. This happens at the same time that the magnetic poles switch (see previous paragraph).
Solar Flares:
When the magnetic field lines on the Sun become too tangled, it causes a solar flare. Solar Flares are huge explosions and bursts of light that occur when the magnetic field lines have been stretched to breaking point, much like a rubber band that snaps when it has been stretched too far. When the magnetic field 'snaps' it releases a huge burst of electromagnetic radiation, including X-rays, ultraviolet radiation, visible light and radio waves. This explosion is more than a million times more enormous than a volcanic eruption. At the time of a solar flare eruption it can be accompanied by a coronal mass ejection. These ejections can be damaging even on Earth, and nowadays, with our reliance on electronics and the Internet, it could cause major disruption in our everyday lives with its ability to harm satellites. Solar flares are visible in white light and via their X-ray and ultraviolet emissions, and are most common during the solar maximum of the sunspot cycle.
Prominences:
Prominences are loop like structures that come out from the surface of the Sun into the solar disk (chromosphere and corona). Although they look to be very ablaze and high in temperature, they are in fact hundreds of times cooler and denser than that of the surrounding atmosphere from the corona. They are dense clouds of incandescent ionized solar gas that are held in their place by the magnetic fields. They last much longer than solar flares, from a few days to a few weeks. They can extend over many thousands of kilometres across the Sun's disk. The largest in record was approximately 800 000km in length (roughly the radius of the Sun).
Solar eclipse:
On the 14th of November 2012, Mackay experienced a phenomenon that occurs only once every 200 years in the same place (approx.). This occurrence was a solar eclipse (see below). A solar eclipse is where the Sun is blocked out almost entirely by the moon for a short period of time. This is because the Sun is much larger than the moon, however it is much farther away, so therefore both objects appear the same size in our sky. When the moon passes over the Sun it casts a shadow over the part of the Earth that it is appearing on that spreads in a narrow path reaching from east to west. Due to this narrow path, only a few places across the Earth experienced the totality of the solar eclipse. Meaning that the Sun's light was dimmed by a factor of about a million. At this point, only the corona and chromosphere was able to be seen. Just before the point of totality comes the last light of the Sun shining over the moon. This is called Bailey's beads.
Although it is only a medium star, the sun makes up around 98% of our solar system's mass. It is able to fit 1.3 million Earths in its interior and 110 across. 109 Earths can fit across the Sun's disk, which adds up to about 1.4 million kilometres. The sun is neither a solid nor gas but a substance called plasma. Plasma is a tenuous and gaseous substance. It is thinner on the outer layers of the Sun but becomes more dense towards the core.
Layers:
Similar to the Earth, the Sun is divided into layers. However, the Sun's layers are just a few thousand or million degrees hotter. The first of the Sun's layers is the core, coming up to approximately 15 000 000°C. It is in this section of the sun that fusion of hydrogen to helium takes place, providing the Sun with its light, heat and energy. Second is the radiative or radiation zone which is used as an efficient means of transferring heat and energy (radiation) from the core to the outer regions, but first it must pass through the next layer called the convective zone. The convective zone is the next stage of transferring this energy, however, the convective zone is much cooler than the radiative zone so energy has to be transferred in a different way. The bottom of the convective zone is much hotter (200 000°C) than its upper part (only about 5 700°C). This is due to the radiation which causes an effect much like boiling water. The 'boiling' effect is the cells in the plasma being in a state of turbulence. Since hot substances are lighter that cool substances, radiation and energy is carried up to the upper layers inside individual bubbles of hot plasma. When it reaches the top, some of the radiation and heat is released and becomes part of the photosphere. The continuous bubbling from the convective zone can be seen on the photosphere, this is called granulation. The photosphere is the part of the Sun visible to the naked eye or the visible surface (although no person should look at the Sun without some sort of eye protection), it is the layer of the Sun where light is emitted. From the core to the photosphere the temperature drops to only about 6000°C from the initial 15 million°C. It is on this layer that sun spots are found. Just above the photosphere is the chromosphere. The chromosphere a region of the Sun that usually can not be seen due to the fact that the light from the photosphere overpowers it. However, during the total point of a solar eclipse, it appears to look like a red ring surrounding the Sun with an irregular outer edge. The red colour of the chromosphere can also be seen in prominences when they project from the Sun. It is approximately 2 500km deep and is the layer where prominences and solar flares take place. It is also the region where spicules occur and spread into the corona lasting about 15 minutes. Spicules are jets of plasma shooting up from super granule boundaries. The corona is the last layer of the Sun. It extends further than one million kilometres out from the Sun's surface and can be more than a million degrees. That is the puzzling fact about the corona, despite the fact that the Sun cools dramatically from the core to the photosphere, the corona, which in theory should be cooler than the photosphere is approximately over 1 million degrees. Scientists have hypothesised that the reason for the corona's heat is to do with the magnetic fields covering the Sun. The corona also emits strong electromagnetic X-rays.
Magnetic fields:
The magnetic fields of the Sun are generated from its interior out to the solar system through the solar wind. Since the Sun is rotating, it winds up this magnetic field to form a spiral named the Parker spiral (after the scientist who described it). However, since the Sun is made of plasma, the gaseous sphere rotates faster at the equator than at its poles. Therefore each hemisphere projects the Parker spiral in opposite directions, one moving outwards and one moving inwards. Every 11 years, the magnetic fields of the Sun flip (magnetic north pole becomes south pole and vice versa). The magnetic fields of the Sun can be described as 'ropes' with one end coming out making an arch and diving back into the photosphere. The contrasting rotations of the Sun, as mentioned, are believed to be the cause of the Sun's magnetic fields. Due to the faster and slower rotations at the poles and equator, the overall magnetic field becomes distorted and twisted and this eventually reaches the surface. These 'ropes' and the twisted field lines can be seen through sunspots.
Sun Spots:
Sunspots are the darker regions visible on the surface of the Sun. They are believed to be cooler 'spots' on the Sun than the rest of the photosphere. In fact, sun spots only appear to be dark since the other parts of the Sun are so bright. If you took a sun spot and placed it in space, it would be as bright as a full moon during the night. Some of these sunspots can even be planet sized. Sunspots, as mentioned in the previous paragraph, are formed through the movement of magnetic fields. The points where the magnetic north and south poles of the 'ropes' meet the photosphere are where sunspots are located. Due to there being two poles for each 'rope', sunspots usually come in pairs meaning that one sunspot has north polarity and the other has south polarity. Sunspots move across the surface of the Sun and change their whereabouts yearly. However, scientists have been able to determine that there is a type of cycle which the sunspots appear. This is called the sunspot cycle and occurs approximately every 11 years. This happens at the same time that the magnetic poles switch (see previous paragraph).
Solar Flares:
When the magnetic field lines on the Sun become too tangled, it causes a solar flare. Solar Flares are huge explosions and bursts of light that occur when the magnetic field lines have been stretched to breaking point, much like a rubber band that snaps when it has been stretched too far. When the magnetic field 'snaps' it releases a huge burst of electromagnetic radiation, including X-rays, ultraviolet radiation, visible light and radio waves. This explosion is more than a million times more enormous than a volcanic eruption. At the time of a solar flare eruption it can be accompanied by a coronal mass ejection. These ejections can be damaging even on Earth, and nowadays, with our reliance on electronics and the Internet, it could cause major disruption in our everyday lives with its ability to harm satellites. Solar flares are visible in white light and via their X-ray and ultraviolet emissions, and are most common during the solar maximum of the sunspot cycle.
Prominences:
Prominences are loop like structures that come out from the surface of the Sun into the solar disk (chromosphere and corona). Although they look to be very ablaze and high in temperature, they are in fact hundreds of times cooler and denser than that of the surrounding atmosphere from the corona. They are dense clouds of incandescent ionized solar gas that are held in their place by the magnetic fields. They last much longer than solar flares, from a few days to a few weeks. They can extend over many thousands of kilometres across the Sun's disk. The largest in record was approximately 800 000km in length (roughly the radius of the Sun).
Solar eclipse:
On the 14th of November 2012, Mackay experienced a phenomenon that occurs only once every 200 years in the same place (approx.). This occurrence was a solar eclipse (see below). A solar eclipse is where the Sun is blocked out almost entirely by the moon for a short period of time. This is because the Sun is much larger than the moon, however it is much farther away, so therefore both objects appear the same size in our sky. When the moon passes over the Sun it casts a shadow over the part of the Earth that it is appearing on that spreads in a narrow path reaching from east to west. Due to this narrow path, only a few places across the Earth experienced the totality of the solar eclipse. Meaning that the Sun's light was dimmed by a factor of about a million. At this point, only the corona and chromosphere was able to be seen. Just before the point of totality comes the last light of the Sun shining over the moon. This is called Bailey's beads.