I just read the article "Catch a manmade Star" by Philip Chien. It is really interresting for me, because it provides me a lot of useful information. Before reading this article, I always think that satellites are moving around the earth from a very far distance. I never think that they can be visible by naked eyes. At night, whenever I look up the sky and see some lighted dots moving. I though , they are the stars. But now, I know that may be some satellites.... Who know? or a plane. I will try , if I have time . I will save this article to my computer...