This Is New To Me

For the past few nights the moon has appeared larger than many people have seen it for almost 20 years. It is the world's largest optical illusion, and one of its most enduring mysteries.

It can put a man in space, land a probe on Mars, but Nasa can't explain why the moon appears bigger when it's on the horizon than when it's high in the night sky.

The mystery of the Moon Illusion, witnessed by millions of people this week, has puzzled great thinkers for centuries. There have even been books devoted to the matter.

Not since June 1987 has the moon been this low in the sky, accentuating the illusion even further.

But opinion differs on why there is such an apparent discrepancy in size between a moon on the horizon and one in the distant sky.