The Speed of Light

Light travel at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000 km. but sound travels only .344km. 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 come 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 which you can see from it tonight started to travel toward 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 started on its journey to you before you were born.

Thus, if we want to be honest, we cannot say, “The start are shining” tonight. “We have to say,” The stars look pretty. They were shining four years ago but their light has only just reached Earth.”

Vocabulary:

l   watching the start of a race觀看比賽的開始

l   starter[tkfFqfR](n.)賽跑時的發令員

l   come from來自;出生於,來自於;

l   take about大約花費

l   far away遠處, (離...)很遠

l   toward(prep.)向,朝;接近,將近

l   nearly(ad.)幾乎,差不多;近似

l   in some cases在某些狀況下

l   journey[tgYPna](vi.n.)旅行;旅程,行程

l   thus(ad.)如此,這樣,以此方式;因此,從而

l   honest[tFnakf](a.)誠實的;正直的;真誠的,坦率的;真正的;不攙雜的;

l   shining[tXAanaV](a.)光亮的;醒目的;優秀的;華麗的;