Tuesday, June 10, 2014

The History in the Night Sky

This is a speech I made for our speaking class at STBA LIA Yogyakarta. It is an example of an informative speech. We were free to choose whatever topic we liked. I chose to talk about one of my favorite subjects: the universe.

I hope it can be a satisfactory example for those who need to make a semi-formal informative speech in English.

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The History in the Night Sky

Imagine a typical date held outdoors at night. The boyfriend says, “Look at the sky”. The girlfriend looks at the black canvas decorated with millions of blinking lights. “It is beautiful,” she says. Romantic, right?

How many of you have ever been in this situation? If not, I believe all of you have seen what the sky looks like on a clear night, when the stars are scattered everywhere. However, as you were admiring their beauty, did you ever think about what the stars really are? Did the science behind their existence strike you at all?

In this opportunity, I would like to tell you about the amazing scientific and philosophical fact behind the beauty of the stars. Don’t get bored yet! Stay with me. I promise you it will be interesting (I hope).

I will deliver three major points: 1) What stars are, 2) Where they are in the universe 3) The light-year concept.

Firstly, what is a star? A human being on earth gazing at the night sky would see a tiny, blinking dot in the night sky. However, in the universe, that pretty speck is actually a gigantic ball of gas floating far, far away in our infinitely large universe. The closest star to earth is actually our sun. It is the center of our solar system. It is the miracle that gives the earth life.

Secondly, where are they in our universe? To get a brief glimpse of how far stars are, lets us start with our sun. Most of the time, we don’t think of our sun as a star because, to our eyes, it is this giant ball that we can see on the horizon at dawn or sunset. The other stars are tiny blinking lights. This is because, compared to other stars, our sun is very, very, very close to earth. The sun is 150,000,000km away from our earth. Meanwhile, the closest star to our solar system is Alpha Centauri, which is about 4 light-years away.

Thirdly, what is a light-year? Very literally, it is the distance light travels in a year. To grasp just how extraordinarily vast this is, let’s remind ourselves how fast light travels. The speed of light in a vacuum (c) is 299,792,458m/s. It is approximately 300,000km/s. Now, sunlight takes about 8 minutes and 17 seconds to travel the average distance from the surface of the earth. This value is achieved by dividing 150,000,000km by approximately 300,000km. The result is the value in seconds, so about 500 seconds. Since there are 60 seconds in a minute, divide 500 by 60. This is about 8 minutes and more. So, when you wake up at dawn and you see the first rays of sunlight, realize that the sun sent those rays to you 8 minutes ago and it had to wait 8 minutes for you to wake up and feel it.

So, can you get any idea how far is a light-year? There are 60 seconds in a minute, 3600 seconds in an hour, 86,400 seconds in a 24-hour day, and 31,536,000 seconds in 365 days or a year. Now, multiply that by the distance at which light travels in a second (300,000km/s). You get 9,460,800,000,000km. That is the distance light travels in a year. You can go round and round the earth at current humanely possible speeds for a hundred years and you will barely cover that distance.

Now, most stars are light-years away – light “years”. There is an “s” there which means more than one year. The closest star to us, Alpha Centauri, is about 4 light-years away. So, it is 9,460,800,000,000km times 4. The result? Very, very, very far away. Airplanes today travel at thousands of km per hour. Rockets cover probably tens to hundreds of thousands km per hour. It is like the speed of a very slow snail compared to the speed of light. But even if man managed to build a vehicle that could travel at the speed of light, it would take a human being 4 years just to reach Alpha Centauri.

Here on earth, Alpha Centari is a really bright star. However, that star sent you light four years ago for you to be able to see it tonight. It is like receiving a letter from your beautiful girlfriend or boyfriend who lives so far away that it takes 4 years for the mailman to give it to you. So the letter you get today was made 4 years ago. Talk about a long-distance relationship.

Again, most stars are light-years away. Some are even millions of light-years away. The average human lives for 60-80 years on earth. If a star is 1,000,000 light-years away, light had to travel 1,000,000 years to reach you. The view of the star you get today is the view of the star 1,000,000 years ago.

I’ll give you a moment for this to really sink in.

By looking at the night sky, we can see the past. We see what the sky was years ago. We travel back in time without moving. Meanwhile, the condition of the stars right now is something we cannot see yet. Actually, it is already happening, and we do not know it is. We can’t see it happening now, but we may see it in the future. The future is already happening somewhere in the universe.

More interestingly, a star can be born and another star can die. What if a star somewhere in the heavens just died? However, because it is 100 light-years away, we can’t see it die. In the view from earth, it hasn’t disappeared from the sky yet. As humans on earth, we can still admire its light which was sent 100 years ago. We can still see it twinkling in the sky until the day we die, and we will never see it fade away and disappear.

I want to quote my source, Fajri Matahati M., who used to study Physics at UGM: “What if life is not a four-dimensional stream, flowing from start to end? What if everything is one eternal timeless movement, where all time and space overlaps? Is the future already happening now? Is the past still happening?”

He calls the dead stars “real ghosts” because the start seen at night might have died already. “So what you see is a mere imprint. Imagine that”.

What we see in the night sky is actually history. We see stories of the stars from the past. We travel through time with one look, and we might have never realized it.

We may never grasp how extraordinary, how infinite, and how mysterious the universe is. However, we can prove that God is indeed the Divine for creating it. Think of how much love was put into it. The sun got up 8 minutes earlier than you so it could say hello to you each morning. Millions of stars were made and they had to be born so many years ago so they could wink merrily at you tonight, and some of them keep on twinkling, even years after they pass away. They wait patiently to reach you and they are there for you even when they are gone. To me, that is romantic. That’s true love.

I hope these facts can benefit you in some way. At least, you will look at the sky differently, and maybe send Him a compliment or two.

As an end to this speech I would like to quote my favorite scientist, Albert Einstein:

“Watch the stars, and from them learn. To the Master’s honor all must turn, each in its track, without a sound, forever tracing Newton’s ground.”

Thank you for your attention.