The Sun Chapter 14.2

Standard 8.2.g. Students know the role of gravity in forming and maintaining the shapes of planets, stars and the solar system 8.4.b. Students know that the sun is one of many stars in the Milky Way galaxy and that stars may differ in size, temperatures, and color.

Introduction The sun accounts of 99.8 percent of the solar system’s total mass. The sun exerts a powerful gravitation force throughout the entire solar system,

Energy from the Sun ¾ of the sun’s mass is hydrogen Nuclear Fusion The sun produces energy through nuclear fusion. Nuclear Fusion: two atomic nuclei combine forming a larger more massive nucleus and releasing energy

Energy from the Sun

Energy from the Sun Core: the central region of the sun The temperature within the core reaches about 15 million degrees Celcius This energy reaches Earth as light and heat Forces in Balance Astronomers estimate that the sun will be stable for another 5 billion years or so

The Sun’s Interior The sun’s interior consists of the core, the radiation zone, and the convection zone The Core: 400,000 km, more than 30 times the Earth’s Diameter

The Sun’s Interior The Radiation Zone: region of very tightly packed gas where energy is transferred mainly in the form of electromagnetic radiation The Convection Zone: The outermost layer of the sun’s interior.

The Sun’s Atmosphere The sun’s atmosphere includes the photosphere, the chromosphere, and the corona The Photosphere: part of the sun that gives off visible light Photos = light

The Sun’s Atmosphere The Chromosphere: The glow comes from this layer Chroma = color The Corona: Looks like a white halo around the sun In Latin = Crown Extends into space for millions of kilometers, and gradually thins into streams of electrically charges particles called the solar wind

The Corona

Features on the Sun Features on or just above the sun’s surface include sunspots, prominences and solar flares. Sunspots: areas of gas on the sun’s surface that are cooler than the gases around them Since the sunspots seems to change location, this means the sun rotates on its axis, like the Earth does.

Features on the Sun Prominences: huge, reddish loops of gas Solar Flares: eruptions that happen on the sun Solar Wind: can affect Earth’s magnetic field.