判断正误Light travels at a speed which is about a million times 急.The Speed of Light　　Light travels at a speed which is about a million times faster than the speed of sound.　　In one second,light travels about 300,000 kilometres.　　But sound travels only 0.344 kilometres .You can get some idea of this difference by watching the start of a race.If you 　　Stand some distance(距离) away from the starter,you can see smoke come from his gun　　(枪) before the sound re

判断正误Light travels at a speed which is about a million times 急.
The Speed of Light
　　Light travels at a speed which is about a million times faster than the speed of sound.
　　In one second,light travels about 300,000 kilometres.
　　But sound travels only 0.344 kilometres .You can get some idea of this difference by watching the start of a race.If you
　　Stand some distance(距离) away from the starter,you can see smoke come from his gun
　　(枪) 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 left the moon 1.3 second before they reached you.The nearest star is far away from the earth.The light which you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million kilometers one minute.In some cases(情况) the light from one of tonight’s starts started on its journey to you before you were born.
　　If we want to be honest(诚实),we can not say “The stars are shining tonight.” We have to say,“The stars look pretty(漂亮).They were shining four years ago.But their light has only just reached the earth..”
　　判断正误：
　　（ ）1.Light speed is about a million times faster than sound speed.
　　（ ）2.If you stand 100 metres away from a starter,you can hear the gun before you see the smoke.
　　( )3.The moon must be about two million kilometers away from the earth.
　　( )4.The sun must be about 480 times300,000 kilometres away from the earth..
　　( )5.The moonlight we see tonight started to travel towards us four years ago.