LAYERS
OF THE SUN – SCI & TECH
News:
Aditya-L1: Sun mission
enters final orbit, PM Modi congratulates ISRO
What's
in the news?
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Aditya-L1 spacecraft carries seven
payloads to observe the photosphere, chromosphere and the outermost layers of
the Sun (the corona) using electromagnetic particle and magnetic field
detectors.
Layers
of the Sun:
There are six layers of
layers of the Sun under two major headings.
Core:
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The core is the deepest layer of the sun, where nuclear fusion events take place.
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It is the hottest region of the sun having
a temperature of more than 15 million
degrees Celsius.
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The pressure at the core is roughly 250
billion times that of the Earth's atmosphere.
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Because of the extreme pressure and
temperature, hydrogen atoms fuse together, producing helium atoms and
unleashing a massive quantity of energy in the form of light and heat.
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The energy created in the core is
distributed across the other layers of the sun.
Radiative
Zone:
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The radiative zone surrounds the core.
This layer stretches from the core to around 70% of the radius of the Sun.
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Radiation transfers energy across the Sun
in the radiative zone.
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Light
photons are created in the core by fusion processes and
travel outward through the thick gas of the radiative zone.
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When they exit the Sun, photons are
absorbed and re-emitted multiple times by the gas particles in the zone.
Convection
Zone:
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The convection zone is the outermost layer of the interior of the sun.
This layer stretches from approximately 70% of the radius of the Sun to the
visible surface, or photosphere.
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Convection transports energy across the
Sun in the convection zone.
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Hot
gas rises to the top, while colder gas sinks back to the core, resulting in a
continually churning action.
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The core structure of the Sun influences
its magnetic activity as well. The migration of electrically charged particles
in the convection zone produces the Sun's magnetic field.
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The rising and falling of the gas in the
convection zone produce large-scale movements that generate the Sun's magnetic
field.
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Many of the Sun's dynamic phenomena,
including sunspots, solar flares, and
coronal mass ejections, are influenced by its magnetic field.
Photosphere:
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All
the visible light from the Sun comes from the Photosphere.
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It has a thickness of about 500 km.
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It is the coolest part of the sun with temperature coming down to 5500°C.
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The temperature drops with an increase in
height.
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Phenomena such as Sunspots occur in the
photosphere.
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Sunspots
are the dark spots on the Sun’s surface.
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They
are formed due to magnetic fields and the region becomes
cooler (about 500° – 1500°C) and darker than the surrounding.
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Lifetime of sunspots varies from a few
days to a few months.
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It believes that the Sun is 1% cooler in
the absence of Sunspots. The absence of Sunspots might affect the Earth’s
climate.
Chromosphere:
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The Chromosphere lies just above the
Photosphere.
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The
visible light from the chromosphere is seen only during Solar Eclipses when the
Photosphere is hidden.
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It is visible as a red dim ring.
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The temperature increases with the
increase in height.
Transition
Region:
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A small layer of the Sun's atmosphere
between the chromosphere and the corona is known as the transition area.
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The temperature rapidly rises from roughly
10,000 degrees Celsius in the chromosphere to several hundred thousand degrees
Celsius in the corona.
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The precise mechanisms causing this
temperature increase are unknown, although they are considered to be connected
to the Sun's magnetic field.
Corona:
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The Corona layer lies above the
Chromosphere.
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It is the outermost layer of the Sun’s atmosphere.
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It is visible during a total Solar Eclipse
as a glowing white corona.
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The temperature
on the Corona reaches up to
2-million-degree Celsius, the reason of which is still unknown.
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The phenomena associated with Corona are
Coronal Mass Ejection, Solar Flares, and Solar Winds.
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Coronal
Mass Ejection (CME) is the release of plasma and magnetic field in a large
amount.
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Solar
Flares are the instantaneous flash of increased brightness
which occurs when magnetic energy is suddenly released
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Solar
Wind is the flow of energized, charged particles at a very high speed. It
is made up of plasma and mostly contains electrons, protons, and alpha
particles.