Light travels at a speed which is about a million times faster than the speed of sound. You can get some idea of this difference by watching the start of a race. If you stand some distance  away from the starter, you can see smoke from his gun before the sound reaches your ears. This great speed of light produces some strange facts. Sunlight  takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light rays left the moon 1.3 seconds before they reached you. The nearest star is so far away that the light that you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million km. per minute. In some cases, the light from one of tonight's stars had started on its journey to you before you were born. Thus, if we want to be honest, we can't say, "The stars are shining tonight." We have to say instead, "The stars look pretty. They were shining four years ago, but their light has only just reached the earth." The scientific way of saying "The stars are shining tonight" should be   _  .
the stars have been shining all the time the stars seen tonight will shine four years later the stars were shining long ago but seen tonight the starlight seen today could be seen four years ago