It happens at least once every month. Sometimes, rarely, it happens twice a month. It’s when lunatics roam the streets and when drivers get distracted by what they see up there in the sky. It’s a bird. It’s a plane. No, it’s a FULL MOON.
Yesterday, inspired by the beautiful sight of the Moon outside my window and soon after reading Thomas’s post about impact craters on the different hemispheres of the Moon, I wanted to find out if there were others around the world who were also thinking about the Moon. It turned out there were lots of people tweeting about the Moon (hashtag analysis suggested atleast hundreds of tweets per hour). Historical statistics suggested the around this time of each month, the webosphere goes wild about the Moon and so I began digger deeper. I plotted data from Google Trends and noticed how periodic peaks in searches for the keywords “Big Moon” coincided with the days around a full moon. Over the last few years, since social media took over the world, annual Supermoon events sparked the most interest with about 4 times as many Google searches than a typical day in the year.
So, what’s the fascination with the size of the Moon?
Once a month, every moonth*, the Earth prepares for an evening celestial date with the Sun. She asks the Sun, “Does My Moon Look Big In This?” As the Sun slowly sets in the west, as if in perfect synchrony, he can just make out the rising Moon in the east and finds that the Earth’s Moon does look kinda big. However, as many Earthly men have answered when faced with this tricky question, the Sun devotedly replies to his blue sweetheart: “No, my dear, it looks great! In fact, it looks smaller than when we last met!”
It’s almost certain you have seen this yourself: The Full Moon rises** over the horizon, bloated and fat. But a few hours later it is high in the sky and appears much smaller. You’ve just experienced the Moon Illusion.
Find out why this phenomenon, most prominent around days surrounding a full moon, has got astronomers, psychologists and brain researchers stumped.
Now, let’s find out how close the Moon really is and how quickly you could get there with a folding Gedankenexperiment.
But you have to be quick because the Moon is getting away from us – thanks, in part because of the celestial dance between the Sun, the Earth and the Moon. The belly dancing action of the oceans on Earth means that Earth’s rotation is slowing down (as the Moon pulls back on its tidal bulge). One hundred years from now, the day will be 2 milliseconds longer than it is now and the Moon will be about 4 meters further away. These numbers might seem small but over millions and billions of years they add up. Dinosaurs, for example had half an hour less to chew and poo in their 23.5 hour day!
In the past the Moon was closer to the Earth, perhaps even appearing 10 times as big as it does today, and in the future it’ll be farther away.
But let’s enjoy the Moon while we can in this Southern Hemisphere view of 2013 Lunar phases.
If you’d like to find out what causes the phases of the Moon, you can join this inquisitive NASA kid.
That’s all for today folks! Until our next date under the stars when we all turn into lunatic*** werewolves, enjoy the moonshine!
* The word “Month” may have been derived from the word “Moonth”, referring to the 29.53 day cycle of the phases of Moon.
** The Moon illusion can also be experienced during Moonset at dawn but a warm cosy bed often provides a comfortable incentive to miss the phenomenon.
*** Legend has it that the full moon brings out the worst in people: more violence, more suicides, more accidents, more aggression. Belief in the Lunar Effect was widespread throughout Europe in the middle ages. Even the word “lunacy” meaning “insanity” comes from the Latin word for “moon.” However, there is little scientific evidence to support these beliefs.