Kewl!!
Posted on 06/18/2008 2:49:28 PM PDT by lainie
As the full moon rises this Wednesday evening, June 18, many people will be fooled into thinking it's unusually large.
The moon illusion, as it's known, is a trick in our minds that makes the moon seem bigger when it's near the horizon. The effect is most pronounced at full moon. Many people swear it's real, suggesting that perhaps Earth's atmosphere magnifies the moon.
But it really is all in our minds. The moon is not bigger at the horizon than when overhead.
The illusion will be particularly noticeable at this "solstice moon," coming just two days before summer starts in the Northern Hemisphere. The reason, according to NASA, lies in lunar mechanics: The sun and full moon are like kids on a see-saw; when one is high, the other is low. This week's high solstice sun gives us a low, horizon-hugging moon and a strong, long-lasting version of the illusion.
If it's any consolation, space station astronauts report the same effect.
Here's how it works: Your mind believes things on the horizon are farther away than things overhead, because you are used to seeing clouds just a few miles above, but the clouds on the horizon can indeed be hundreds of miles away. So if we think something (such as the moon) is farther away, and it's not, then it seems larger.
If you remain doubtful, test the idea yourself. Go out at moonrise with a small object, perhaps a pencil eraser. Hold it at arm's length as the moon rises and compare the sizes of the moon and the eraser, then repeat the experiment an hour or two later when the moon is high in the sky. A rolled up tube of paper works well, too.
Moonrise times vary by location. On Wednesday, it will come up at these local times at these locations, according to NASA: New York City, 8:58 p.m.; Miami, 8:35 p.m.; Seattle, 9:51 p.m.
The moon rises about 50 minutes earlier Tuesday night, when the effect will also be noticeable because the moon will be nearly full. Oh, and that raises another fallacy: There's no such thing as a full moon.
Additional moonrise times for your location are available from the U.S. Naval Observatory Web site.
Kewl!!
This view of a full moon was photographed by an Expedition 14 crewmember onboard the International Space Station. Earth's horizon and airglow is visible at left. Credit: NASA
HUGH !
What, Bill and Hillary! are on the same stage?
bump
That lainie is always posting the cool threads. Glad I stumbled on it.
While I have been enjoying a few days of cloudy and cool weather, I kind of hope it clears this evening so I can see this moon. I have a thing about the moon.
What, Bill and Hillary! are on the same stage?
No, that's a Huge Loon Illusion.
I saw this once but in the early morning on the way to school. The moon appeared huge, much larger than the mountain it was rising behind. I doubt it was all in my mind because about two hundred people, teachers and students, were just standing there staring at it. It lasted about 15 minutes and was one of the coolest things I’ve ever seen.
I doubtit was in your mind, too.... since it actually IS larger than any mountain! ;^)
When my kids were small, they used to ask me why the moon was ‘following us’ as we drove down the road.
Telling them it just looks like it’s following us because it’s very big and very far away just produced blank looks.
Yeah, sure Dad...
I have seen this effect many times in my years of travel. There has to be some sort of lensing effect because it seems 5 times larger.
...and series...
The moon appeared huge, much larger than the mountain it was rising behind...
...imagine what the Moon looked like millions of years ago when it was a mere 15,000 miles or so from earth...can you imagine the tidal effects?
You can test this by comparing your thumb held at arms length to the moon while it is close to the horizon and appears large.
Do it again when the moon is high in the sky and you will see that the moon’s size relative to your thumb doesn’t change.
Just your perspective.
Thanks for posting this. I’ll be looking for it. I have the most amazing view from my deck...no light pollution/air pollution. I bought a Barska telescope and viewing the Moon’s craters is just awesome.
ping
Kewl, indeed.
I was out lookin’ at the moon last night and believe it or don’t, I was seeing one and a half moons directly over one another.
I took off my glasses and the ‘second’ moon appeared smaller. Glasses back on and tipping my head to adjust the view through my progressive (not a gay thing) bifocals it changed shapes again.
I’ll try it again tonight without the benefit of Jim Beam. :)
Huge Moon,
You saw me standing a-lone......
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