Question

What is the cause of red moon???

Answer 1

this happens mainly during the LUNAR ECLIPSE,, thts bcoz

The reason is that during total eclipse, while the moon falls into the "shadow" of the earth; some sunlight that passes through the earth's atmosphere will actually be refracted (yes, I mean refraction, not reflection) to the earth's shadow, ultimately reaching moon, and then gets reflected back to us. 

The refracted sunlight is always in the reddish-orange colors, in a way not too unlike why the color of sunset is always reddish-orange.

Depending on the specific condition of the earth's atmosphere (amount of dust, cloud, etc.), the amount and the color of the sunlight refracted to the moon via the earth's atmosphere varies, resulting in different colors you see during total lunar eclipse, ranging from bright orange  to extremely dark red. Hence, scientists use the color of the moon during total lunar eclipse to gauge the condition of the earth's atmosphere too.

Answer 2

hey here ur best ans..
Earth and moon line up so that the moon passes through the Earth’s shadow,This causes moon to appear a dull red color due to sunlight scattered through the Earth’s atmosphere...hope its help uu☺☺☺