The Sun

1. The Sun
By Hafsah, Khyati, Amber, Abigail

2. Contents
• Introduction
• The Three Layers of The Sun
o The core
o The Radiative layer
o The Convective layer
• The Three Atmospheric Layers
o The Photosphere
o The Chromosphere
o The Corona
• Sun Spots
• Solar Prominences
• Solar Flare
• Spicules
• Fun Facts

3. Introduction
Our star, the Sun, makes up 99% of all the mass in
the Solar System. Its core is so dense and hot that
normally repellent nuclei fuse together in nuclear
reactions that produce vast amounts of energy. The
Sun is mostly hydrogen and helium, and radiates
charged particles called solar wind across the Solar
System.

4. The Three Layers of The Sun:
The Core
The core starts from the center and extends
outward to encompass 25 percent of the sun's radius.
Its temperature is greater than 15 million degrees
Kelvin. At the core, gravity pulls all of the mass
inward and creates an intense pressure. The pressure
is high enough to force atoms of hydrogen to come
together in nuclear fusion reactions

5. The Three Layers of the Sun :
The Radiative Layer
The radiative zone extends outward from the core,
accounting for 45 percent of the sun's radius. In this
zone, the energy from the core is carried outward by
photons, or light units. As one photon is made, it
travels about 1 millionth of a meter (1 micron) before
being absorbed by a gas molecule. Upon absorption,
the gas molecule is heated and diffuses another
photon of the same wavelength.

6. The Three Layers of The Sun:
The Convective Layer
The convective zone, which is the final 30 percent of
the sun's radius. 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.

7. The Three Atmospheric Layers:
The Photosphere
The photosphere is the innermost region of the sun's
atmosphere and is the region that we can see. "The
surface of the sun" typically refers to the
photosphere. It is 300-400 kilometers wide and has
an average temperature of 5,800 degrees Kelvin. It
appears granulated or bubbly, much like the surface
of a simmering pot of water. As we pass up through
the photosphere, the temperature drops and the
gases, because they are cooler, do not emit as much
light energy.

8. The Three Atmospheric Layers:
The Chromosphere
The chromosphere extends above the photosphere to
about 1,200 miles (2,000 kilometers). The
temperature rises across the chromosphere from
4,500 degrees Kelvin to about 10,000 degrees Kelvin.
The chromosphere is thought to be heated by
convection within the underlying photosphere.

9. The Three Atmospheric Layers:
The Corona
The corona is the final layer of the sun and extends
several million miles or kilometers outward from the
other spheres. It can be seen best during a solar
eclipse and in X-ray images of the sun. Although no
one is sure why the corona is so hot, it is thought to
be caused by the sun's magnetism. The corona has
bright areas (hot) and dark areas called coronal holes.
Coronal holes are relatively cool and are thought to be
areas where particles of the solar wind escape.

10. Sun Spots
Dark, cool areas called sunspots appear on the
photosphere. Sunspots always appear in pairs and are
intense magnetic fields that break through the
surface. Field lines leave through one sunspot and re-
enter through the other one. The magnetic field is
caused by movements of gases in the sun's interior.

11. Solar Prominences
Occasionally, clouds of gases from the chromosphere
rise and orient themselves along the magnetic lines
from sunspot pairs. These arches of gas are
called solar prominences. Prominences can last two to
three months and can extend up to 50,000 kilometers
or more above the sun's surface. Upon reaching this
height, they can erupt for a few minutes to hours and
send large amounts of material racing through the
corona and outward into space at 600 miles per
second which are called the coronal mass ejections

12. Solar Flares
Sometimes in complex sunspot groups, abrupt, violent
explosions from the sun occur. These are called solar
flares. Solar flares are thought to be caused by
sudden magnetic field changes in areas where the
sun's magnetic field is concentrated.

13. Spicules
As gases churn in the photosphere, they produce
shock waves that heat the surrounding gas and send it
piercing through the chromosphere in millions of tiny
spikes of hot gas called spicules. Each spicule rises to
approximately 3,000 miles above the photosphere and
lasts only a few minutes.

14. Fun Facts !!
• The sun rotates on its axis once every 25.38 Earth
days or 609.12 hours.
• A person weighing 150 pounds on Earth would weigh
4,200 pounds on the sun because the sun’s gravity is
28 times that of Earth.
• Existing for about 4 and a half billion years, it has
burnt up about half of the hydrogen in its core. This
leaves the Sun's life expectancy to 5 billion more
years.
• Only 55% of all Americans know that the sun is a star.

15. How is the sun measured??
Solar tsunami used to measure Sun’s magnetic field
A solar tsunami observed by NASA's Solar Dynamics Observatory (SDO) and
the Japanese Hinode spacecraft has been used to provide the first
accurate estimates of the Sun's magnetic field.
Solar tsunamis are produced by enormous explosions in the Sun's
atmosphere called coronal mass ejections (CMEs). As the CME travels
out into space, the tsunami travels across the Sun at speeds of up to
1000 kilometres per second.
Similar to tsunamis on Earth, the shape of solar tsunamis is changed by the
environment through which they move. Just as sound travels faster in
water than in air, solar tsunamis have a higher speed in regions of
stronger magnetic field. This unique feature allowed the team, led by
researchers from UCL's Mullard Space Science Laboratory, to measure
the Sun's magnetic field.