On 27 July 2018, there will be a longest total lunar eclipse , during which the moon appear a lot bigger and also red.And the eclipse can be seen for the whole one hour. So ,what causes the moon to turn red?.This question baffled scientists for many years , but with new technology, it has been discovered that the moon turns red , when the earth blocks the light coming from the sun to the moon , it casts two shadows called the penumbra and umbra shadow . The penumbra gives of a blue light that deflects the red colour to the umbra which is the darkest shadow , since no light gets to moon , the deflected red colour cast a red colour on the moon. If the moon keeps on going round and round the earth then we should get a lunar eclipse every month.Instead , we get a lunar eclipse once every year.Why