Staring at the full Moon, Joshua feels his skin begin to itch. Looking down, he sees thick hairs appearing on the back of his hand. Before long the hair has spread all over his body; his fingers and toes have turned into claws; his teeth have become razor-sharp. He feels a deep need to howl. "This is what I am," he thinks. "A werewolf!"

Legends about the Moon's effect on humans have existed for many centuries. And though scientists do not believe in werewolves, some are convinced that the movement of the Moon does influence how we feel.

At the end of this week, a 33-foot asteroidA small body in space, made of metal and rock material. Asteroids usually orbit the sun, but if knocked off course they can be drawn into Earth's gravity and fall towards it. named 2024 PT5 will be captured by our planet's gravity and pulled into a horseshoe-shaped orbit around Earth. But on 25 November, pulled by the Sun, it will start to move back towards the asteroid belt from which it came. Experts classify such temporary visitors to our orbit as "mini-moons."

Sadly, we will not be able to see 2024 PT5. Not only is it a fraction of the Moon's size, but it will be five times further away.¹

Because mini-moons are relatively tiny, they are hard to detect - so nobody is sure how many Earth has had. We know about 2024 PT5 because it was picked up last month by a network of telescopes called the Asteroid Terrestrial-impact last alert system. This was created to warn of asteroids that could damage Earth.

2024 PT5 is travelling at around 2,200 mph. According to Professor Derek Richardson of Maryland University: "To become a stable moon orbiting us, the object would need to lose a lot more speed... The dance will only last a little while."

The Roman philosopher Pliny the ElderGaius Plinius Secundus (23 - 79AD), better known as Pliny the Elder, studied botany and philosophy in Ancient Rome and created the first known encyclopaedia. thought that the full Moon made dew heavier, and that this created extra moisture in the brain, which led to madness. The term "lunatic" derives from the Latin word for the Moon, and was defined in the 1700s as "one who hath lucid intervals, sometimes enjoying his senses and sometimes not and that frequently depending upon the changes of the Moon".²

Writing in Discover, Kate Golembiewski suggests a reason for this belief. Because our ancestors slept less well when the Moon was bright, tiredness sometimes made them behave oddly. A study in 2013 found that even in the 21^st Century people sleep on average for 20 minutes less during a full Moon.³

In the 1970s a psychiatristA doctor who specialises in diagnosing and treating mental illnesses. called Arnold Lieber argued that because around 70% of the human body is water, we are affected by the phases of the Moon in the same way as ocean tides are. He claimed that murders and suicides increased dramatically during a full Moon.  

Later studies have contradicted this. A Finnish one even found that there were fewer murders.

But a few years ago a professor of psychiatry, Thomas Wehr, noticed a strange pattern among 17 of his patients during a full Moon. They suffered from rapid-cycling bipolar disorderA mental condition affecting mood, which can swing between extremes. , which makes people switch quickly between depression and mania.

He found that with some the mood swings followed a 14.8-day cycle, while others followed a 13.7-day cycle - mirroring the two cycles of ocean tides.⁴

Will it affect our mood?

Yes: Many extremely intelligent people through the ages have believed that heavenly bodies exert an influence over us, and Professor Wehr's findings cannot simply be put down to coincidence.

No: Even if we accept that our own Moon has an effect us, which is doubtful, this mini-moon is so small and will be so far away that it cannot possibly make any difference to anything.

Or... It might cheer us up. Most people get excited by celestial phenomena, from shooting stars to solar eclipses, and this could be a welcome distraction from our problems here on Earth.