The moon has been turning red at the end of October 2019, leading to theories about what’s causing it.
The moon has been turning red in the last few days, which is leading to all sorts of theories about what’s causing it. The phenomenon is being dubbed a “blood moon” and is said to be caused by a lunar eclipse. The blood moon effect occurs when the Earth passes between the sun and the moon, casting a shadow on its surface. This causes light from the sun to shine through Earth’s atmosphere onto the moon, making it appear red.
However, people have also been reporting that they can see green and blue hues on the surface of the moon as well as red. So why does this happen? A lunar eclipse only occurs when there is a full moon, so that rules out some of these colours. Some people have speculated that there might be dust or smoke in Earth’s atmosphere that are causing these other colours to appear on the surface of our satellite.
Why does Earth’s atmosphere make a blood moon turn green?
What causes a blood moon?
The light from an eclipse makes our planet’s atmosphere glow.
“During an eclipse [the] Moon travels through our planet’s shadow,” says astronomer Dr Dave Reneke from Sydney Observatory.
“This means that some sunlight falls on parts of our planet which are usually in darkness.”
“As sunlight passes through our atmosphere it gets scattered around by air molecules,” he says.
“This scatters blue light more than red light — so when we look at things close to sunset or sunrise they often take on a reddish hue.”