Guiding Questions. What is the source of the Sun’s energy? What is the internal structure of the Sun? How can we measure the properties of the Sun’s interior? How can we be sure that thermonuclear reactions are happening in the Sun’s core? Does the Sun have a solid surface?
L = 3.9 x 1026 watts (or joules per second)
The Sun is powered by thermonuclear fusion reactions in the core, where hydrogen is converted into helium, releasing energy in a process called the proton-proton-chain.
Einstein’s equation, E = mc2 describes how much energy, E, can be created from an amount of mass, m.The Sun’s energy is generated by thermonuclear reactions in its core.
At extremely high temperatures and pressures,
4 Hydrogen atoms can combine to make 1 Helium atom
and release energy by E = mc2
4H He + energy
Thermonuclear fusion can only occur at very high temperatures and pressures.
Sections of the Sun’s surface quickly oscillate up on down.
Cl + n Ar + e-
n + n p + e-
Granulation caused by convection Sun’s atmosphere.
Most easily seen during an eclipse. Sun’s atmosphere.
Thin gas at millions of degrees
The outflow of mass from the Sun is called the solar wind.The corona ejects mass into space to form the solar wind.
Magnetic fields cause structure, heating, and energy outbursts from the Sun’s atmosphere.
Flares and mass ejections
Temperature changes on Earth
Sunspots are low-temperature regions in the photosphere. outbursts from the Sun’s atmosphere.
Maunder Minimum ~ 1650
Mideval Maximum ~ 1100
This X-ray image of the Sun shows bright regions where gas follows magnetic field lines.
The sunspot cycle is partly due to the Sun’s differential rotation. This helps solar magnetic fields twist up, intensify, emerge, cancel, then repeat the cycle.
The interior of the Sun rotates at slower than the equator and faster than the poles.
The radiative zone seems to rotate as a rigid sphere.
not just cell phone users.