Hello again, and welcome back to – So, You’re Interested in Astronomy?
If you remember, so far we’ve looked at a number of brilliant facts about the Solar System itself, and one of its smallest members, Pluto. This time, we’re going to delve into 10 interesting things you might want to know about the biggest member of our Solar System…The Sun.
Have you got your sunglasses ready? Then let’s begin.
Do you know the Sun has an orbit? To appreciate this, you need to know where the sun is within the Galaxy. Look at this picture of the Milky Way…no, not the chocolate bar…we’re talking about our home. (Look Mom! Can you see me waving?)
Our Sun is positioned between 25,000 – 30,000 light years out from the center, near the edge of one of the spiral arms. Just as well, really, as lots of radiation exists around the hub and that would cause us to get very sick indeed. Because the Sun lives so far away from the middle, it takes her over 225 million years to complete just one orbit! (Even though she travels along at a speed of 220 kilometers/140 miles per second.
Like many of her satellites, the Sun is made up of a number of layers. Unlike the planets, however, the Sun is made up of incandescent gas. The core is where the energy is produced. It is also here where pressure is the greatest, and where temperatures may be as high as 15 million degrees Celsius! Next, comes the Radiative zone. After that, is the Convective layer. Then we come to the bright surface we actually see – the Photosphere. Temperatures here are only 5500 degrees Celsius, and it is within this zone that we see the familiar dark sunspots and bright faculae. Above the photosphere comes the Chromosphere, a layer of much more rarified gas. Finally, we come to the place regarded by many as the Sun’s outer atmosphere, the Corona.
The diameter of the Sun is just under 1 ½ million Kilometers, (865 thousand miles). But, because the Sun isn’t solid, it rotates at different speeds. For example, the equator completes one revolution in 25 ½ Earth days. But if you were at the poles, it would take 34 days! Yes…The Solar Day is a different length depending where on the Sun you are…weird!
So, think about that for a moment. If I was born on the equator of the Sun, and had a twin brother who was born on the North Pole, does that mean he’d be younger than me after a year or two?
Actually, it would help explain why some ladies I know keep saying they’re younger than they are. We all know where they must have been born now. J.
Our star lies at the center of the Solar system at a distance of just under 150 million kilometers, (just under 93 million miles), from Earth. Because of this, the sunshine we enjoy takes eight minutes to reach us.
The Sun makes up over 99% of the mass of the entire Solar System. In fact, if you wanted to fill the Sun with pebbles the size of planet Earth; you’d need over a million of them to get near to finishing the job. Not that you’d like living there if you managed it. Why? Because you’d be thirty – yes 30 – times heavier and always on a diet!
Even though she looks big to us, the Sun isn’t really all that impressive on an interstellar scale. Why? Well, look at the picture.
As you can see, some Stars are so small, even out own sun seems like a giant in comparison. But, look how tiny the Sun looks against the red giant, Antares.
And guess what? She isn’t the biggest star we know. Betelgeuse, another red giant, is more than twice as big as Antares!
Stars get a letter and number according to their spectral brilliance and surface temperature. Our little Sun is merely a G2 Dwarf Yellow baby. But thankfully, she looks after us quite well, yes?
Now this is a really good question. Just because it’s ‘the Sun’ doesn’t automatically mean every day is wonderful day. Why?
Well, don’t forget, the Sun’s energy comes from nuclear transformation in its core where temperatures and pressure are colossal. The Sun is made up of over 70% hydrogen. The Sun radiates energy by transforming hydrogen into helium (the next heaviest element). To do so, it has to burn 4 parts of hydrogen to get 1 part helium. It is the energy of this transformation that causes the sun to shine.
Just look at the process in this photo…
So, the next time you’re enjoying a sunny day, just remember, to do that, the Sun has to endure a never-ending mega storm of storms, each and every single second!
Well, what I should say is, the Sun generates a Solar Wind. The solar wind is made up of charged particles, (plasma), sent out by the sun, every second of every day. The average velocity of this phenomenon is 300 – 400 kilometers, (190 – 250 miles) per second, and they extend out as far as the edges of the Solar System
What do I mean?
Well, look at these pictures below.
Without the solar wind, we wouldn’t see the spectacular sight of a comet’s ion tail, (which makes the tail point away from the sun), nor would we be able to enjoy the awesome sights of the Aurora Borealis, (northern hemisphere)/Aurora Australis, (southern hemisphere).
Now, that might sound depressing. But it will happen so far ahead – perhaps trillions of years – that we needn’t worry about it for a long time.
So, there you go. 10 interesting things about our own Sun.
But a word of caution.
Remember, the greatest care must be taken when looking at the sun. Never look at it directly, either with your own eyes, through binoculars or a telescope. Instead, use your telescope as a projector, and focus the Sun’s image onto a piece of card. You’ll be delighted at just how clearly you will be able to see things.
Next time, how about we look at our closest neighbor, the Moon? She is an excellent source of wonder for all budding astronomers, and you’ll be amazed how much fun it can be.
See you soon J