Page:A Voyage in Space (1913).djvu/290

270 The names in the first column need not concern you further than to notice that they are mostly of a weird kind; clearly these are not familiar stars, but small fry; and the brightness in the second column shows this even more clearly. They are stars which are chiefly of interest to astronomers because of their rapid movements shown in the third column: and you see that they all have measurable "squint" and are within 100 light years of us. The last column shows that they are probably much smaller than the former stars.

The table therefore shows that if a star seems to be moving quickly it is probably nearer us than other stars: if very slowly it is probably far away. But again we must not be too sure in either case, because appearances are often deceptive. Have you ever noticed a train coming nearly straight at you from a long way off? When you are waiting at a station sometimes the lines curl round a corner, so that you do not see the train till it is pretty close; but sometimes they run straight for a long distance and then you can see your train coming from a long way off. It looks no bigger than a toy train, and moreover it seems to be quite still. You know that it is coming towards the station (at least you hope so if it is the train you want to join), but you cannot see it move because it is coming at you end-on. It might even be going the opposite way for all you can tell by looking at it. Similarly, if a star seems to us to remain nearly still, we must not be too hasty in thinking that it has very little movement of any kind, and therefore it is very far away, for it may be coming directly at us, or going directly away from us; by merely watching