The sun is a star which is
very closer to earth than any other star and appears very
large and bright. Without the Sun's light and heat, there
would be no life on Earth.
The Sun is a ball of plasma with a mass of about 2×1030
kg. The sun is mainly composed of hydrogen and helium; it
contains about 70% of hydrogen, 28% of helium and less than
2% of other metals. The outer atmosphere of sun has a temperature
of over 106 K when its visible surface (the photosphere) has
a temperature of just 6,000 K. Solar energy is transformed
by plants into chemical energy, which is the first step in
the food chain for all living things. The Sun has been around
for about 4.6 billion years and is expected to keep burning
bright for another 5 billion years.
| Observation
Data |
Mean
distance from
Earth
|
149.6×106
km
(92.95×106 mi)
(8.31 minutes at the Speed of Light) |
Visual brightness
(V) |
-26.8m |
Absolute magnitude |
4.8m |
| Orbital Characteristics |
Mean distance
from
Milky Way core |
2.5×1017
km
(26000 light-years) |
Galactic period |
2.26×108
a |
Velocity |
217 km/s |
| Physical Characteristics |
Diameter |
1.392×106
km
(109 Earths)
|
Oblateness |
9×10-6 |
Surface area |
6.09×1012
km²
(11 900 Earths)
|
Volume |
1.41×1018
km³
(1 300 000 Earths)
|
Mass |
1.9891×1030
kg
(332 950 Earths)
|
Density |
1.408 g/cm³ |
Surface gravity |
273.95 m s-2
(27.9 g)
|
Escape velocity
from the surface
|
617.54 km/s |
Surface temperature |
5780 K |
Temperature
of corona |
5 MK |
Core temperature |
~13.6 MK |
Luminosity (Lsol) |
3.827×1026
W
3.9×1028 lm
or 100 lm/W efficacy |
Mean Intensity
(Isol) |
2.009×107
W m-2 sr-1 |
| Rotation Characteristics |
Obliquity |
7.25°
(to the ecliptic)
67.23°
(to the galactic plane) |
Right ascension
of North pole 1 |
286.13°
(19 h 4 min 30 s) |
Declination
of North pole |
+63.87°
(63°52' North) |
Rotation period
at equator |
25.3800 days
(25 d 9 h 7 min 13 s) 1 |
Rotation velocity
at equator
|
7174 km/h |
Photospheric
Composition (by mass)
(All in the plasma state) |
Hydrogen |
73.46 % |
Helium |
24.85 % |
Oxygen |
0.77 % |
Carbon |
0.29 % |
Iron |
0.16 % |
Neon |
0.12 % |
Nitrogen |
0.09 % |
Silicon |
0.07 % |
Magnesium |
0.05 % |
Sulfur |
0.04 % |
