The Sun is the star at the centre of the Solar System and is by far the most important source of energy for life on Earth.
Diameter
13,90,000
Mass
1.989e30 kg
Temperature
5800 K (surface) 15,600,000 K (core)
Planet
Distance (000 km)
Mercury
57,910
Venus
108,200
Earth
149,600
Mars
227,940
Jupiter
778,330
Saturn
14,26,940
Uranus
28,70,990
Neptune
44,97,070
The Sun is, at present, about 70% hydrogen and 28% helium by mass everything else ("metals") amounts to less than 2%.
This changes slowly over time as the Sun converts hydrogen to helium in its core.
It just happens that the Moon and the Sun appear the same size in the sky as viewed from the Earth.
And since the Moon orbits the Earth in approximately the same plane as the Earth's orbit around the Sun sometimes the Moon comes directly between the Earth and the Sun.
This is called a solar eclipse; if the alignment is slightly imperfect then the Moon covers only part of the Sun's disk and the event is called a partial eclipse.
When it lines up perfectly the entire solar disk is blocked and it is called a total eclipse of the Sun.
Partial eclipses are visible over a wide area of the Earth but the region from which a total eclipse is visible, called the path of totality, is very narrow,
just a few kilometres (though it is usually thousands of kilometres long). Eclipses of the Sun happen once or twice a year.
