Stars And Galaxies

The Sun

LET’S EXPLORE http:// evula.org/solarsystem/sun.html

THE CHARACTERISTICS OF THE SUN • The centre of the Solar System • The biggest object in the Solar

System • Formed of mainly hydrogen, helium and other substances • Rotates from the west to the east • The main source of energy for the Earth

THE SOLAR SYSTEM

THE COMPARISON BETWEEN THE SUN AND THE EARTH

• •

DIAMETER 1 392 000 km 109 x the diameter of Earth

• •

DENSITY 1485 kg/m³ 0.27 x the density of Earth

• •

MASS 1.989 x 1034 kg 333 420 x the mass of Earth

SURFACE EMPERATURE

• 5100 – 6000 °C • 227 – 273 x the

temperature of Earth

THE SUN’S STRUCTURE

SUN

CORE

PHOTOSPHERE

CHROMOSPHERE

CORONA

CORE  The centre of the

sun  Made up of gaseous  Nuclear reactions occur  Temperature : 15 000 000 °C

PHOTOSPHERE

• The layer of light

that can be seen from the Earth • Considered as a surface of the Sun • Temperature : < 6000 °C • The venue for sunspots, solar flares , prominences and solar winds

sunspot

solar flare

Sun Prominenc e

CHROMOSPHERE • A red-glowing region of gas • Part of the solar atmosphere • Temperature : ±15 000 °C

CORONA • The outermost

layer • Made up of a thin layer of gas • Temperature : 2 000 000 °C • Can only be seen during the full eclipse of the sun

ECLIPSE OF THE SUN

corona

Phenomena Occurring At The Surface of The Sun

SOLAR FLARES

PROMINENCE

SUNSPOTS

SOLAR FLARES • Explosion of solar • • •

material Several thousand to million kilometres long Release huge amount of energy Emit radiations such as X-rays and atomic particles

PROMINENCES • Visible only during • • •

total eclipses The masses of glowing gas Suspended above the surface by the loops of magnetic field Can remain quiet and stable for days and weeks

Total solar eclipse in 1973 showing the corona

SUNSPOTS

• Darker patches on the photosphere • Cooler regions • Appear in groups • Not permanent

The effects of the phenomena

on the surface of the Sun on the Earth

• A flow of gaseous (solar wind)

disturbs and shakes the Earth’s magnetic field • Current surges in power lines • Heat up the Earth’s upper atmosphere • Change the orbits of satellites

Generation of Energy by The Sun Light

+ Light + Hydrogen

Heat

Helium

• Nuclear fusion takes place at the core • Hydrogen atom bang into each other constantly and fuse •

into atoms of helium releasing huge amount of energy The energy generated is carried to The Sun’s surface as heat and light

The End