BLOGS

SCIFI SCHOOL by Odis Chenault

http://www.kelonproductions.com/category/scifi-school/

EP.2 the Size of the Universe

Hello and welcome to the second installment of SciFi School.

One of the things that make scifi so great is the scope of it all. Scifi authors have an infinite canvas on which to create their masterpieces. What scifi fans take for granted is that most people rarely think about how vast the universe truly is.

Let’s be clear. No one knows its exact size! It’s infinite. Geniuses keep trying to calculate the size of the universe. All I know is that every time our best telescopes look deeper into space, we just see more galaxies.

Let’s talk size. In scifi, size matters. When I break this down to people, I like to start small and build out. So you’re in a in a city. The city is on a continent of a planet. The planet is orbited by a moon. The planet and moon orbit a star (or sun) named Sol. Sol is also orbited by seven other planets (used to be 8), their respective moons, an asteroid belt and some comets. This star or solar system is part of a Galaxy. Besides star systems, galaxies have black holes and nebula (huge clouds of gas). There are an infinite number of galaxies. Now, add in quasars, dark matter and dark energy and there’s your known universe.

Now we have an idea of what’s in the universe, but how big is it? Again, let’s start small. The Earth is around 25,000 miles in diameter. The sun is one million times the size of the Earth. There is a Hyper Red Giant Star (VY Canis Majoris) that is 7 Billion times the size of our sun. Our galaxy (the Milky Way) has over 300 Billion stars.

 In between all this visible stuff is space and lots of it. We use light years (6 trillion miles) to describe distances in space because we need a huge unit of measure. The closest star to our sun is Proxima Centauri. Proxima Centauri is 4 light years away. When we look at it, the light reaching our eyes has been traveling 186,000 miles per second for 4 years to get here. There are stars in our galaxy that would take us over 10,000 years to reach at the speed of light. That’s one galaxy. The next closest galaxy is the Canis Major Dwarf Galaxy. This small galaxy is 25,000 light years away. Andromeda, the next closest spiral shaped (like ours) galaxy is 2.5 million light years away. There are galaxies over 13 billion light years away.

Here’s some fun with distance and light. When you look at a star that is a hundred light years away, you see it as it was then. If it exploded 50 years ago you wouldn’t see the explosion for 50 more years because the light from the explosion is only half the way here. If you look into the night sky and find a dark area, stare at it and you will soon see a star. Your eyes act like telescopes in an observatory. Sometimes the light is so faint; your eyes need time to collect enough light to register an image.

So let’s recap. The visible universe is endless. It’s mostly empty space (calm down dark matter and dark energy super geek nerds, we’ll talk later). Things are super far apart and getting farther every day. Now you see why it’s a big deal in scifi when aliens arrive from another star. The mere fact that they covered the distance alone speaks of their superior technology. You can only imagine what else they are capable of. Why have they come? You get the picture. Isn’t scifi wonderful?