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Top Ten Interesting and Fun Facts About the Sun
The Sun is the most important celestial body for the maintenance of life.
The Sun gives us light, heat and astrophysicists have now worked out that it provides very nearly 100% of all the energy at the Earth's surface.
In this article, we'll look at some of the facts not only about this astonishing star itself but the history of our relationship with it and its influence on life on Earth.
A Blazing Star in the Heavens
Sun Worship in Ancient Times
Not surprisingly, the Sun was worshipped by the primitive peoples of ancient times and is still revered as a god or goddess by many surviving indigenous cultures today.
The Sun God, Apollo.
In the earliest Chinese civilizations it was believed that a solar eclipse (when the Sun or part of it is blocked from view by the passage of a planet between it and the Earth) was caused by the 'dog of heaven' taking a bite out of it!
The Central American Aztecs offered bloody human sacrifices to their sun-god, Huitzilopochtli. They believed that without these sacrificial offerings the Sun would no longer be able to make its daily journey across the sky.
The ancient Egyptian culture endured for over three thousand years. During that time there were many versions of the sun god. One of the most popular was Khepre the Scarab Beetle. Just as the real beetle rolls balls of dung across the ground, so it was thought that the divine version rolled the Sun across the sky.
The ancient Romans and Greeks had very similar sun gods called Apollo and Helios. These guys had blazing sun-chariots that the rode across the sky.
Many of the sun gods were said to be sacrificed and die, to be reborn after a journey to the underworld. This symbolizes the setting and rising of the actual Sun.
The Christian myth of Easter, with the death and resurrection of Jesus, is based in the same solar tradition. And the symbol of the 'halo' which is placed behind the heads of saints in Christian art is a solar symbol from ancient times.
Secrets of the Sun
The Sun and the Seasons
In ancient times it seemed obvious that the Sun travelled across the sky.
The misunderstanding is easily forgiven. After all, from where we stand on the surface of the Earth, it does look as if the Sun rises in the east in the morning, moves across the sky during the day and sets in the west.
Antique Astronomical Map of the Seasons
But it doesn't. It's an illusion.
It certainly doesn't make the journey in a mystic barge or celestial chariot chased by heavenly dogs!
If you stand on a carousel, you will have the impression that the world is spinning around you. But you know better. You know that the world is relatively still and you are the one doing the spinning.
Earth's Orbit and the Astronomical Seasons
The reason why the Sun appears to make its journey across the sky is because the Earth itself is turning eastwards on its own axis. So the earth is spinning around the Sun and on its own axis. This explains not only the cycle of day and night but also the progression of the seasons.
So how is it that the Sun seems to shine brighter and longer in the summer than in the winter?
We've said that the Earth's spinning axis is tilted towards the Sun. In the northern hemisphere (where the USA and the UK are) the height of summer takes place in June. In June the northern hemisphere is tilted towards the Sun, and in the opposite month of December it is tilted away.
In the southern hemisphere (where you'll find China, India, most of Africa for example) the situation is the other way around.
Heading further to the north or the south, one way or the other, the area exposed to the Sun's light and heat is greater or lesser.
And if you go north of the Arctic Circle, then at midsummer the sun never sets at all!
Check out this great little video that explains everything in an easy to understand and fun way:
The Sun and the Seasons Explained
The Sun is a Star
Because of the Sun's importance to all our lives here on Earth, we tend to think of it as being unique.
The truth is, however, that the Sun is just one of literally billions of other stars very much like it.
The Milky Way - Home to 100 Billion Other Suns.
- How old is the Sun? About 4.5 billion years old
- What kind if star is the Sun? It's a Yellow Dwarf
- What is the Sun's diameter? Approximately 865, 373 miles
- What's the surface temperature of the Sun? 6000 °C
In our own galaxy, known as The Milky Way, there are about 100 billion other suns. Add to that the fact that there are many billions of other galaxies out there and you'll begin to see that in the larger scheme of things, our Sun is not so unique after all!
Not only are there many other Sun-like stars out there but many of them support their own planetary solar systems, too.
Most modern astrophysicists now accept that it is more likely than not that some form of biological life exists on many of those planets circling those distant stars.
So if the Sun isn't unique, the chances are that we aren't, either.
The Birth of The Sun
How Was the Sun Formed?
Our Sun was formed about 4.6 billion years ago, making it almost one third as old as the entire known Universe.
The Sun started out as a vast cloud of particle debris left over from the explosive death of an even older star somewhere else in the Universe.
Most of the particles were hydrogen, which is the most common element in existence.
Nuclear Fusion is the Source of the Sun's Energy
The forces of gravity caused all these particles to be drawn towards one another. So the swirling mass of particles became denser and denser, slowly collapsing in on itself.
This process generated a huge amount of heat energy as a consequence of friction between the particles.
When a certain temperature and speed was achieved, the nuclei of the atoms fused together to form helium.
This process is called nuclear fusion, and it generates massive bursts of radiation in the form of gamma-rays. It takes the gamma-rays formed in the Sun's core about one million years to reach the Sun's surface. Yes, the Sun is very, very big!
As the gamma-rays travel, they change their frequency until they emerge from the Sun's surface and out into space as visible light.
The Electromagnetic Spectrum and Visible Light
Light is one frequency range of a universal force called electromagnetic energy.
There is enough heat and hydrogen left in the Sun for it to live another 4 billion years before it explodes just as the parent star that provided the original material for its own formation did.
And who knows? Maybe our Sun will start the whole process off all over again. But life on Earth will have become extinct in the cold and the dark long, long before then.
A New Star Forming
How Hot is the Sun?
The Sun is very, very, very hot!
The Sun's core - the site of all that nuclear fusion we've just been discussing - is the hottest part and is a scorching 15 million degrees Celsius. That's 2.7000 x 107degrees Fahrenheit.
As I said, pretty hot.
The surface of the Sun is relatively cool being a mere 6 thousand degrees Celsius.
However, the Sun's surface isn't the same temperature all over. If it is observed through special filters, areas known as sunspots can be observed.
Sunspots and Solar Flares
Sunspots are areas where irregular fluctuations in the Sun's magnetic field cause solar protrusions. Theses sunspots in themselves are cooler than the rest of the star's surface.
However, while they are cooler in themselves, the electromagnetic activity they cause can often result in a phenomenon known as a solar flare.
Solar Flares and CMEs
Solar flares are projectile bursts of high energy X-rays.
They cause CMEs - coronal mass ejections - which is the most explosive event in our whole solar system. When this occurs, huge quantities of hyper-electrically charged gas particles known as plasma are projected out from the surface.
In March 2012 there was quite a scare which gathered a lot of media attention when a vast CME was seen to be heading earthward.
The anxiety was that the electromagnetic influence of such an event could have caused a 'radio blackout' leaving the entire planet without electricity or communications!
However, in the end the impact was not as great as had been feared. In fact, the most noticeable effect was an increase in the number and size of auroras in the Northern Hemisphere which produced some of the most beautiful ever seen.
How Long Before the Sun Dies?
The Sun will not go on forever.
Eventually it will burn up all its fuel and eventually die.
Once the hydrogen element has been completely consumed, the Sun will then begin to burn up its helium. This process will go on for about one hundred thirty million years.
The Sun as a Red Giant
How Far Away is the Sun?
The distance from the Earth to the Sun varies with the time of year as our planet undergoes an elliptical solar orbit.
At its nearest point, the Sun lies some 86, 991, 966 miles from the Earth. At its furthest away, it is about 94, 448, 420 miles off.
The average distance between the Earth and the Sun is used as a standard of measurement in astronomy and is known as an Astronomical Unit or AU.
Average walking speed is three miles an hour. How long would it take to walk to the Sun?
During that time the area of the Sun will begin to expand and it will become much brighter and hotter to the point where it will destroy life on Earth, evaporate the oceans and eventually consume the entire planet along with our nearby planets, Mercury and Venus.
The Sun is a kind of star known as a Yellow Dwarf but at that stage it will have become a Red Giant.
There is another phase following that as, once the expansive energy is all burned up, the Sun will contract again until it is a dense nugget about the size of the Earth that it will have destroyed. Stars at this stage are called White Dwarfs.
Stunning Images from the NASA Solar Observatory
Sun Quiz: Time to test Your Solar Knowledge!
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Bye bye, Sun!
And so our journey to the Sun comes to an end. Pretty hot stuff, right?
There's a lot more to learn about our nearest star and you can find out more by visiting the NASA website and searching the solar observatory.
If you have something to say or a question you'd like to ask, please go right ahead and do so in the comments box below. It would be great to hear from you!
Have you tried the Sun Quiz?
Give it a go and see how you do!
NB: Never look directly at the Sun with naked eyes, binoculars or a telescope. You could permanently damage your eyesight.
© 2014 Amanda Littlejohn