A Super Blue Blood Moon

A Super Blue Blood Moon certainly sounds spectacular but what really makes this event special is that it is three individual events lining up.

On Wednesday 31 January, a Super Moon, a Blood Moon, and a Blue moon will all occur at the same time. But what do these names actually mean for our closest cosmic companion, the Moon, and what will we be able to see in the UK?

Supermoon

A ‘Supermoon‘ is the name given to the coincidence between a full or new moon and the point when the Moon is the closest to the Earth.

This is only really noticeable during a full moon when it is bright and visible in the night sky. Because the Moon is closer to the Earth it appears larger in the night sky. But don’t believe the misleading images that make the Moon look enormous compared to its usual size. While the Moon does look bigger because it is closer to the Earth, the actual size increase is only around 14 percent.

This is still a noticeable size increase, especially when the Moon is close to the horizon, so definitely worth checking out on the 31 Jan.

Blue Moon

Typically a month has just one full moon, but because the length of a month (28-31 days) and the length of the lunar cycle (28 days) are different, we occasionally get an ‘extra’ full moon, called a ‘Blue Moon’. Sometimes this is the third or fourth moon in a season, or it is the second full moon in a single month. This month, we’re seeing the latter – January had a full moon at the start of the month on 2 January, making the full moon on 31 January a Blue Moon.

A common misconception is that the Moon changes colour during this period. This, I’m afraid, doesn’t happen, however there have been recorded example of when the Moon does ‘appear’ to turn blue. This happens when there are certain sized particles in the air, usually from volcanoes or forest fires.

Blood Moon

Viewers in the United States get to see a third event on 31 January – a ‘Blood Moon’. This is the colloquial name given to a totally eclipsed Moon, or a Total Lunar Eclipse. A lunar eclipse occurs when the shadow of the Earth moves across the Moon. As this happens, light from the Sun gets refracted and scattered through our atmosphere and some of it makes its way to the Moon’s surface. This scattered light is mainly from the red end of the spectrum, giving the Moon a reddish hue for a few moments during totality. This reddish moon is what is referred to as the Blood Moon.

Sadly for those of us in the UK, this eclipse will occur during our daylight hours and we won’t be able to see it. The next Total Lunar Eclipse visible from the UK will be on 27 July 2018.