Thumb sun
The Sun photographed in Hydrogen Alpha
The Sun is the reason why our Solar System has formed, the planets have stable orbits and we have pleasant temperatures here on Earth. So, there are many reasons to thank the Sun for being with us. The Sun was formed 4.57 billion years ago out of a huge cloud of gas and dust together with many other sister stars in a beautiful star cluster. The former star cluster has disintegrated over time so that the Sun now orbits the centre of the Milky Way unbound to any other star. The dimensions of the Sun are truly amazing: it has a radius of 1.4 million km (109 times that of Earth), 12000 times the surface area of Earth, 333 000 times Earth's mass and 1.3 million times its volume... quite impressive if you consider the size of Earth itself.

The Sun is basically a very big ball of gas and plasma with a temperature of 15 million °C and a pressure of 200 billion bar in its core; perfect conditions to fuse hydrogen into helium. This process converts mass into energy very efficiently: every square metre of the Sun’s surface emits more than 63 megawatts of energy! Our article about stars explains the birth, life and death of a star in more detail.

Name Sun
Mean radius 696 342 km
109 Earths
Surface area 11990 Earths
Volume 1 300 000 Earths
Mass 1.9891 x 1030 kg
333 000 Earths
Mean density 1.408 g/cm2
Equatorial surface gravity 274 m/s2 (27.94 g)
Min. surface temperature 3000 K
(on sunspots)
Mean surface temperature 5777 K
Max. surface temperature 15 000 000 K
(in the core)
Oribital period 25.05 days
Click on an image below to see it full size
Sun in Hydrogen Alpha Sun in Hydrogen Alpha
Solar system to scale Solar system to scale
The Solar Surface The Solar Surface
Granules on the Sun's Photosphere Granules on the Sun's Photosphere
Solar flare Solar flare
Solar flare on the 31st of August 2012 Solar flare on the 31st of August ...
Plasma Rain - A Special Solar Flare Plasma Rain - A Special Solar Flare
Sizes of stars Sizes of stars

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Published by Published or last modified on 2015-02-18