Program 2 Our Star, the Sun

After viewing the video and participating in one or more of the Hands-On Activities, students will be able to:
• understand that the Sun is a dynamic and changeable star
• describe the key forces which make the Sun shine and drive its variability-nuclear fusion and magnetism
• discuss Sun-Earth connections such as the aurora, and describe their causes.

Program Description
Modern spacecraft and recent missions have revealed a new face of the Sun-a dynamic, variable star, powered by fusion, shaped by magnetism, with a profound and previously unrecognized impact on the Earth through so-called "space weather" and geomagnetic storms.
• "How does the Sun work: Fusion, Convection, Magnetism" (4:50) describes the Sun's composition (mostly hydrogen and helium) and the forces (fusion) and processes (convection and magnetism) that shape our star's visible surface and drive the approximately 11-year solar cycle. Also provides the size and scale of the Sun in relationship to Earth.
• "Sun (n)..." (5:01) looks at our day star as an astronomical object, a typical yellow dwarf star, and compares its size, color and temperature to those of other stars.
• "Sun-Earth Connection" (2:17) shows how magnetic fluctuations sometimes result in explosions on the Sun which blast off "CMEs" or coronal mass ejections. When these arrive at Earth and their magnetic field is aligned in a particular way, interactions between matter and energy from the Sun and Earth's radiation belts trigger the Northern and Southern lights or aurorae (Latin plural of aurora).

Astrophysicist Craig DeForest uses a blow-torch and an ordinary, black kitchen tile to demonstrate how throughout the Universe things glow in specific colors at specific temperatures, a principle which has enabled scientists to discover much about distant stars. Solar researcher Art Poland explains that CMEs are "a billion tons of matter hurtling through space at a million miles an hour." SOHO scientist Barbara Thompson, from NASA's Goddard Space Flight Center, notes that we are the first generation to have a network of spacecraft and giant telescopes able to track CMEs all the way from the Sun to Earth.