What is it about that star that is different every night? It’s just part of the universe, isn’t it? Even though it sounds strange, it really is a phenomenon that should be easy to understand. It would be really easy for someone like me to say, “look at this star, it’s different every night” and not bother to go look at it.
That’s what I was saying, but I don’t think I said it exactly right. I do think I said it more like, “I can’t get my head around this, but I know something is going on, and I know what it is, but I just don’t know what it is.” I mean, I’m not saying its a miracle.
In astronomy, stars are actually made of atoms. This means that they are actually all made up of the same stuff, just in different proportions. This makes them, to all intents and purposes, identical. As a result, when we see the same star, we see the same star. This is called an isochron, and it is a result of the fact stars are all made of the same stuff (albeit in very different proportions).
The phenomenon known as isochronism is even more striking in astrophotography. In this case, the stars we see every night appear to have been chosen to be the same one over and over again. This is called an isochron, and it is a result of the fact that stars are all made of the same stuff but in very different proportions.
And if we’ve noticed that the stars we see every night seem to repeat the same pattern over and over, then we know that the same isochron is happening here too. Our galaxy is the result of billions of stars, each of which is made of a different mixture of hydrogen and helium. And since each of these isochrones has very different proportions of hydrogen and helium, each isochrone is going to be slightly different because each has been drawn randomly and independently.
But that’s not all that is happening here. Because we’re all part of the same galaxy, at the same time, our very own stars are being drawn randomly and independently. Because we’re all part of the same galaxy, we are all drawn from the same isochrone.
This is called redshift.
Redshift is the process by which stars in the same galaxy are being drawn from the same isochrone. It’s a phenomenon that happens naturally as you go towards the center of the galaxy. The farther away from the galaxy’s center you get, the slower you are going to be drawn from the isochrone because more stars are going to have random positions.So each time you make a trip to the center of the galaxy you get more stars randomly drawn from the same isochrone.
For example, we see a few thousand stars in the night sky every night across the southern hemisphere. But then we also see the stars in the northern hemisphere which are all in the same galaxy. In both cases the stars are all drawn from the same isochrone. This natural phenomenon of the same isochrone has been observed in the past and has led astronomers to speculate that it may be a basic property of the universe.
One theory for how the same universe can give us exactly the same stars every night despite the fact that the universe may be billions of years old is that the universe is actually a large collection of galaxies. In other words, these galaxies are all the same size and shape and are all located in the same part of the universe. So when you go to a star in one galaxy, you are actually going to get the same star in the same position in the galaxy.