Andromeda Galaxy
Photo Source: Hubble Space Telescope

We just keep finding out more and more about the universe. As we find out more, more mysteries are found, it is like a double edged sword. I don't know how many of you have been following the recent news about our neighboring galaxies, but we are finding out things that completely change our perception of what space and the objects in it are really like. For example, when we look up into the heavens we perceive a never changing sky. If we look up at the night sky now and ten years from now, we see the same thing. All the stars are in the same places as are the galaxies. The only thing that changes is the position of the planets, but these are very close to us, relatively speaking. What we are perceiving could not be further from the truth. The universe is an ever changing thing full of bodies and masses that are constantly in motion. The problem is that we perceive time in such short slices that we can not see this motion. After all, how can we see a few light years of travel against the background of billions of light years and billions upon billions of stars and galaxies?

Maybe there are beings somewhere whose concept of time is completely different from ours and who will be able to look up in the sky and actually see galaxies moving across the great void? They themselves would probably move so slowly that we couldn't see them move either. This is a very strange thought indeed. So what is the universe really like? It turns out that if you would take a pane of glass and put water droplets on it and tilt it down so that the droplets would move, some would collide with other droplets making bigger droplets while others would just keep going until they slip off. This is about how close I can come to describing our universe. The galaxies are like the water droplets, they slide through the universe. Sometimes they crash into other galaxies and the two galaxies form a bigger galaxy and that one goes hurtling through space, other times there is nothing in their way and they just keep traveling.

Red Indicates Dust And Gas Ripples In Andromeda Galaxy
Photo Source: NASA, JPL, Spritzer Space Telescope

Our nearest large neighbor galaxy is the Andromeda galaxy. Well guess what, this giant is heading this way and it is traveling fast. How fast? About six times the speed of a rifle bullet. There is nothing for us to worry about though, or even our children or their great, great, great, grandchildren. This is because of the great distances that separate galaxies. The galaxy is calculated to hit us in five to 10 billion years and is currently calculated to be two million light years away. Gee, you would think that the calculations would be a little more accurate than that? Well anyway, when galaxies hit, they don't always destroy everything. Everything in a galaxy is far apart, so far that many solar systems will just pass through the colliding galaxy unharmed. Can you imagine that? The sky would look very unusual as object from the colliding galaxy would fill it and there would be some collisions, but not as many as one would imagine.

The Andromeda Galaxy has collided with other galaxies before. Astronomers believe that it collided with the dwarf galaxy Messier 32, also known as M32. How could scientists ever figure this out? It seems that scientists have discovered that when a small galaxy collides head on with a bigger one, ripples are created. These are like ripples in a pond, only in this case they are not water, but gas and dust rings. The waves of rings and dust can be seen projecting outward from Andromeda if you know how to find them. Actually this collision wasn't that long ago in geological terms. It was during the time of the dinosaurs on earth. M32 paid the price, according to astronomers. It is believed that it is only half the size that it was before the crash. Andromeda must have gained mass in the same collision

A Spiral Galaxy Similar To Our Own Milky Way
Photo Source: NASA

We think that we know a lot about our universe, but do we really? Here is a fact that is puzzling scientists all over the world. Why are so many galaxies aligning along the the plane at the center of Andromeda? Our galaxy and Andromeda both have numerous, small, satellite galaxies that we drag along. Andromeda has fourteen known galaxies that it is taking along for the ride and nine of these are now lined up perfectly with it's central plane. So what does this mean? It means that over 80% of the total mass of Andromeda's satellite galaxies are lined up. Why is this happening? I can't answer this question, but I don't feel too bad because neither can anyone else. It is very strange and there is no theory to account for it. It has turned out that Andromeda is a lot larger than first suspected. Tests have shown that instead of the 80,000 light years across size that it was thought to be, it is likely to be 220,000 light years across. This was realized when many other stars were found to be rotating with it.

The Milky Way, our galaxy, has at least two planes that our satellite galaxies are on. This is a preliminary finding and could change in the future. Some scientists think that somehow, dark matter is playing a role in all this, but there is no proof. Dark matter is the stuff that many scientists believe the universe is mostly made up of. What we see is the visible universe, but the thought is that over 85-90% of the universe is invisible and is made of dark matter. Many theories seem to indicate that there is missing matter in the universe. This theory could be entirely wrong when we apply it to satellite galaxies following planes, or it could be partially right or completely right, we just don't have anyway of knowing yet. All we can do for now is look at our closest large neighbor galaxy, Andromeda and try and guess the process that makes it what it is.