Notes 16-2

The Sun

Stars

an object that produces it own energy, including heat and light.

The Sun is a Star

• Star made of hydrogen and helium

• located at the center of the solar system and is also the largest object

• Has a strong gravitational pull which holds planets in orbit

• 4.6 billion years old

The size of the Sun

• If the Sun were a hollow ball more then a million Earths could fit inside it!

• The Sun is an average size star and the largest object in the solar system.

• The Sun looks larger than the other stars that can be seen in the night sky because it is much closer to Earth.

The sun is gas!

• The Sun is a huge sphere made up of mostly of two gases.– 71% of the Sun’s mass is Hydrogen– 27% of the Sun’s mass is Helium– The remaining 2% is Oxygen and Carbon

What happens inside the Sun?

• Hydrogen particles smash together to make helium.

• This smashing is called Nuclear Fusion.• A little bit of mass is a lost when

hydrogen particles combine to make helium.

• The mass in turned into energy• We see this energy as light and heat!

Interior Layers:

• The sun has 3 interior layers:

1) the core

2) the radiation zone

3) the convection zone

The Core

• Most of the energy that the Sun produces is formed in it’s core.

• The Core’s temperature is 10 million to 20 million degrees Celsius.

• The pressure is more than 1 billion times greater then the air pressure of Earth.

Radiation Zone

• Next to the core

• Moves the energy produced in the core in every direction.

• It can take >100,000 years for energy to move out of this layer.

Convection Zone

• Layer next to the radiation layer

• Gasses with different energies move in circles in a way similar to air with different densities.

• Energy moves out of this layer in about a week.

The sun’s atmosphere:

• Has 3 layers:

1) photosphere

2) chromosphere

3) corona

Photosphere

• Is the visible surface of the Sun.

• It is not a solid surface, but rather a layer of thick gasses.

• Gives off visible light

Chromosphere

• Is the inner layer of the Sun’s atmosphere.

• When it can be seen it looks like a red circle around the Sun.

The Corona

• The outermost layer of the Sun’s atmosphere which creates solar winds.

• The corona takes on different shapes around the Sun depending on changes in the temperature of the photosphere.

Solar Flares

• Are bursts (eruptions) of heat and energy that stretch out from the corona and chromospheres into space.

• Sometimes the energy disrupts satellites, interfering with TV, radio, and cell phone communication systems.

Aurora Borealis

• Also called the Northern Lights

• Energy from the solar flares increases solar winds, causing displays of different-colored lights in the upper atmosphere.

• Most often seen in Alaska, Canada, and the Northern United States

Sun Spots

• Solar Flares are also sometimes associated with sunspots

• They are dark spots on the Sun.

• They are regions of the photosphere that have a lower temperature then the surrounding regions therefore they give off less light.