The Sun

I thought it might be fun to warm ourselves up in this chilly month and learn a few facts about the Sun. For instance, did you know…

The Sun accounts for 99.86% of the mass in the solar system.

It has a mass of around 330,000 times that of Earth. It is three quarters hydrogen and most of its remaining mass is helium.

One day the Sun will consume the Earth.

The Sun will continue to burn for about 130 million years after it burns through all of its hydrogen, instead burning helium. During this time it will expand to such a size that it will engulf Mercury, Venus, and Earth. When it reaches this point, it will have become a red giant star.

The Sun is almost a perfect sphere.

Considering the sheer size of the Sun, there is only a 10 km difference in its polar and equatorial diameters – this makes it the closest thing to a perfect sphere observed in nature.

The Sun is travelling at 220 km per second.

It is around 24,000-26,000 light-years from the galactic centre and it takes the Sun approximately 225-250 million years to complete one orbit of the centre of the Milky Way.

The Sun will eventually be about the size of Earth.

Once the Sun has completed its red giant phase, it will collapse. It’s huge mass will be retained, but it will have a volume similar to that of Earth. When that happens, it will be known as a white dwarf.

It takes eight minutes for light reach Earth from the Sun.

The average distance from the Sun to the Earth is about 150 million km. Light travels at 300,000 km per second so dividing one by the other gives you 500 seconds – eight minutes and twenty seconds. This energy can reach Earth in mere minutes, but it takes millions of years to travel from the Sun’s core to its surface.

The Sun is halfway through its life.

At 4.5 billion years old, the Sun has burned off around half of its hydrogen stores and has enough left to continue burning hydrogen for another 5 billion years. Currently the Sun is a yellow dwarf star.

The distance between Earth and Sun changes.

This is because the Earth travels on a elliptical orbit path around the Sun. The distance between the two ranges from 147 to 152 million km. This distance between them is one Astronomical Unit (AU). Deep in the sun’s core, nuclear fusion converts hydrogen to helium, which generates energy. Particles of light called photons carry this energy through a spherical shell called the radiative zone to the top layer of the solar interior, the convection zone. There, hot plasmas rise and fall like the ooze in a lava lamp, which transfers energy to the sun’s surface, called the photosphere.

The Sun rotates in the opposite direction to Earth

with the Sun rotating from west to east instead of east to west like Earth.

The Sun rotates more quickly at its equator

than it does close to its poles. This is known as differential rotation.

The Sun has a powerful magnetic field.

When magnetic energy is released by the Sun during magnetic storms, solar flares occur which we see on Earth as sunspots. Sunspots are dark areas on the Sun’s surface caused by magnetic variations. The reason they appear dark is due to their temperature being much lower than surrounding areas.

Temperatures inside the Sun can reach 15 million degrees Celsius.

Energy is generated through nuclear fusion in the Sun’s core – this is when hydrogen converts to helium – and because objects generally expand, the Sun would explode like an enormous bomb if it wasn’t for it’s tremendous gravitational pull.

The Sun generates solar winds.

These are ejections of plasma (extremely hot charged particles) that originate in the layer of the Sun know as the corona and they can travel through the solar system at up to 450 km per second. In addition to light, the sun radiates heat and a steady stream of charged particles known as the solar wind. The wind blows about 280 miles (450 kilometers) a second throughout the solar system, extending the sun’s magnetic field out more than 10 billion miles. Every so often, a patch of particles will burst from the sun in a solar flare, which can disrupt satellite communications and knock out power on Earth.

The atmosphere of the Sun is composed of three layers:

the photosphere, the chromosphere, and the corona.

The Sun is classified as a yellow dwarf star.

It is a main sequence star with surface temperatures between 5,000 and 5,700 degrees celsius (9,000 and 10,300 degrees fahrenheit).  The label “yellow” is misleading, though, since our sun burns a bright white. On Earth, the sun can take on warmer hues, especially at sunrise or sunset, because our planet’s atmosphere scatters blue and green light the most.

Here’s a few I made earlier.

And one more retro sun to keep this little chap warm. The Sun… we simply wouldn’t be here without it !

Many thanks to the many illustrative contributors today and the fabulous sun facts from The Planets.org and National Georgraphic.com.

Did you learn anything here today that surprised you ?