Space Science 4.1

The Sun produces energy from hydrogen.The Sunonly star in our solar system
far larger than any of the planets
(contains 99.9% of the mass of the entire solar system)
consists mostly of hydrogen gas -> produces ENERGY
How? hydrogen in the Sun’s interior turns into helium
source of light and warmth making life possible on Earth
Energy flows through the Sun’s layers.
The Sun’s Interior
-cooler, less dense as you move away from the center

Core - Sun’s center : very dense + very hot (15 mill °C) -> extreme condition
- hydrogen particles collide and combine to form helium
in a process called : fusion
- fusion releases energy through radiation

Radiative Zone – energy moves from core by radiation through this thick layer
(fusion does not occur, conditions are not as extreme)

Convection Zone – energy moves mainly by convection: transfer of energy from
place to place by the motion of heated gas or liquid

**Energy moves by radiation + convection**
The Sun’s Atmosphere-less dense, hotter as you move outward
Photosphere
- visible layer of the Sun = Sun’s surface
- convection currents beneath causes bumpy texture
Chromosphere- thin middle layer, pinkish light
Corona- Sun’s outermost layer
- varies in shape, extends outward several million km
-chromosphere/corona (hotter) > photosphere
->low densities -> only visible during total eclipse of Sun
(when the Moon blocks the much brighter photosphere)
Features on the Sun
Near the Sun’s surface there are regions of magnetic force called magnetic fields. These magnetic fields get twisted into different positions as the Sun rotates. Features on the Sun appear in areas where a magnetic field is strong creating…….

Sunspots Flares Prominences

Features on the SunSunspots-spots on the photosphere, cooler, seems dim because the
rest of the photosphere is so much brighter
-realized that the Sun rotates
(some parts rotate faster because the Sun is not solid)
Flares-eruption of hot gas from Sun’s surface
-occur near sunspots
Prominences-huge loops of glowing gas that extend the corona connecting two sunspots


Solar Winddef: electrically charged particles that flow out in all directions from the corona

Most solar winds flowing toward Earth is protected by Earth’s magnetic field.
However……
When solar-wind particles enter the upper atmosphere, they release energy,
and produce beautiful patterns of glowing light in the sky called auroras.



Magnetic StormsDuring peaks of sunspot cycle, flares, and other solar activity,
strong bursts of charged particles are released into the solar wind
called magnetic storms.
-can cause power surges
-interfere with radio communication
-destroy orbiting satellite
-poses danger to astronauts
during space flights