Notes The Sun

The Sun The sun contains 99.9% of the mass of the entire solar system.

The Sun The Sun is mostly made of Hydrogen gas. The Sun produces energy when Hydrogen inside the Sun is fused into Helium.

The Sun The Sun is the source of light and warmth that make life on Earth possible.

The Sun’s Layers The Sun is made of gas, but it still has distinct layers.

The Sun’s Layers Energy produced in the center of the Sun flows out in different forms, one of which is visible light.

The Interior The inside of the Sun is made up of three layers that get cooler and less dense as you get farther from the center.

The Interior 1. Core Center of the Sun ~15 million˚C Fusion: Hydrogen particles combine to make Helium, which releases energy.

The Interior 2. Radiative Zone Hot, dense, and thick. No fusion happens here Energy from the core flows out through this layer.

The Interior 3. Convection Zone Convection: the transfer of energy by a heated gas or liquid.

The Atmosphere The outer layers of the Sun are called its atmosphere. Less dense than the interior. Get hotter and less dense as you move outward.

The Atmosphere 4. Photosphere The layer you see when you look at or take a picture of the Sun. Light leaves this layer and arrives at Earth 8 min later Convection currents make the photosphere look bumpy. The Atmosphere

The Atmosphere 5. Chromosphere The middle layer of the Sun’s atmosphere Gives off a pinkish light.

The Atmosphere 6. Corona Outermost layer Changes shape and extends outward for millions of kilometers. Chromosphere and corona are only visible during a total solar eclipse.

Features The Sun’s surface has regions of magnetism called magnetic fields. Magnetic fields get twisted into different shapes as the Sun rotates. Strong magnetic fields create various features on the Sun’s surface.

Features Sunspots: dark spots on the photosphere that are cooler than the surrounding areas.

Features Sunspots follows a pattern that lasts 11 years. At the solar maximum, there are many sunspots. At the solar minimum, there are few or no sunspots.

Features Astronomers first learned the Sun rotates when they saw sunspots moving across the surface.

Features Flare: eruption of hot gas from the Sun’s surface that usually occurs near sunspots. Prominence: huge loop of glowing gas on the surface of the Sun

Solar Wind Solar wind: electrically charged particles that flow out in all directions from the corona.

Solar Wind Most solar wind is guided around Earth by the planet’s magnetic field. When solar wind DOES enter Earth’s atmosphere, it create patterns of glowing light in the sky called auroras.

Solar Wind Auroras are called the Northern or Southern lights because they occur near the North and South poles.

Solar Wind Earth’s atmosphere usually prevents solar wind from reaching the surface. If it does, it can disrupt power lines and interfere with radio communication.

Solar Wind Solar wind is much more dangerous outside the atmosphere of Earth. It can cause problems with satellites and pose a risk to astronauts.