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Low-Hanging Moon Explained

Zonk posted more than 9 years ago | from the watch-your-head dept.

Space 381

gollum123 wrote to mention a BBC article which explains the low-hanging moon of the past few nights. From the article:"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. The mystery of the Moon Illusion, witnessed by millions of people this week, has puzzled great thinkers for centuries. There is still no agreed on explaination for why the moon appears bigger when it's on the horizon than when it's high in the night sky."

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381 comments

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Mr President, Dr. Evil is on the line... (5, Funny)

TripMaster Monkey (862126) | more than 9 years ago | (#12905665)


Good day, gentlemen. As you are no doubt aware, I have perfected a device capable of altering the orbital path of the moon. First of all, I must offer kudos on a most inspired cover story...'illusion' indeed...really, a first rate piece of propagan-da. Of course, you know it cannot last...

You see, gentlemen, things will only get worse...my device, which I've dubbed 'the Lunatrix', will continue destablizing the moon's orbit, drawing it ever closer to our fragile planet. First, abnormally high tidal waves will decimate all costal regions...then, as the tidal influence grows steadily stronger, geological disruptions will occur on a global scale, tearing apart the earth's crust like fresh bread, releasing the liquid-hot mag-ma within. No place on the planet will be safe...civilization as you know it will cease to exist...that is...unless you pay me...

One hundred billion kajillion fafillion dollaaars!!!

<DramaticMusic>

Gentlemen, you have my demands...peace out.

Re:Mr President, Dr. Evil is on the line... (0)

Anonymous Coward | more than 9 years ago | (#12905765)

Offtopic???

This is the most plausible explanation yet!!! ;)

Mod parent up, before the moon gets us!!!

Re:Mr President, Dr. Evil is on the line... (1)

TimothyTimothyTimoth (805771) | more than 9 years ago | (#12905837)

,,,grandparent is either the cause of moonsize or the fastest thinking ever fp or slashdot is predictably slow to report... ... YOU DECIDE!

Re:Mr President, Dr. Evil is on the line... (0, Offtopic)

XanC (644172) | more than 9 years ago | (#12905910)

,,,grandparent is either the cause of moonsize or the fastest thinking ever fp or slashdot is predictably slow to report...

...or he's a subscriber.

Re:Mr President, Dr. Evil is on the line... (0, Offtopic)

TimothyTimothyTimoth (805771) | more than 9 years ago | (#12905932)

granted

Re:Mr President, Dr. Evil is on the line... (1)

TrippTDF (513419) | more than 9 years ago | (#12905917)

For the LOVE of GOD TMM, do you have a job?

Re:Mr President, Dr. Evil is on the line... (0)

Anonymous Coward | more than 9 years ago | (#12905923)

I wonder the same thing... he must have some mad scripts or something that instantly shoot a huge message to his screen with the topic, being a subscriber probably helps him jump on it quicker too.

Obvious. (3, Funny)

Anonymous Coward | more than 9 years ago | (#12905670)

Duh! Because it's closer!

Re:Obvious. (1)

dancpsu (822623) | more than 9 years ago | (#12905731)

They look like models. We can't tell how fast they're moving because we need a frame of reference. Someone find me some clouds!

/obscure?

Actually... (5, Interesting)

objekt (232270) | more than 9 years ago | (#12905787)

Assuming a perfect non-eliptical orbit, the moon on the horizon is farther away than the moon directly overhead by almost half the diameter of the Earth.

Additionally, I wrote a college term paper about this illusion and in my research I found the illusion to be less pronounced in denizens of mountainous areas who have less exposure to things like train tracks that extend straight into the horizon. Without that frame of reference, they are less likely to think of objects near the horizon as necessarily being very away.

Re:Actually... (1)

DerekLyons (302214) | more than 9 years ago | (#12905916)

Additionally, I wrote a college term paper about this illusion and in my research I found the illusion [of a large moon near the horizon] to be less pronounced in denizens of mountainous areas who have less exposure to things like train tracks that extend straight into the horizon. Without that frame of reference, they are less likely to think of objects near the horizon as necessarily being very away.
Except your thesis seems to fail by inspection - because you are comparing apples to oranges. Denizens of mountainous areas often don't see the horizon at all - their line of sight to it is blocked by said mountains. By the time the moon rises to a point where it is visible to them, it's long been above the horizon, and thus is past the point where the illusion occurs.

A more interesting comparison would be between island and coastal peoples and inland peoples - because the two groups have very different horizons.

old news... (5, Funny)

deft (253558) | more than 9 years ago | (#12905674)

some guy who got gods powers is trying to get laid... apparently its taking longer than the last guy i saw try this one.

whoever ranked this "offtopic"... (0)

Anonymous Coward | more than 9 years ago | (#12905806)

seems to have never have seen bruce Almighty...

Re:old news... (3, Funny)

AstrumPreliator (708436) | more than 9 years ago | (#12905828)

Why did you rate this guy Offtopic? I mean come on, Bruce Almighty wasn't that bad. =P

Bruce Almighty flashback (4, Insightful)

JWSmythe (446288) | more than 9 years ago | (#12905679)

This is news?

I was thinking the same thing a few nights ago, watching the moon rise
over LA. Then I considered, "Near the ground, I consider it in proportion to the objects around it. In the sky, I have no reference"

Great thinkers? Centuries? Bah.

Now what they need to figure out is how to fix the pollution in LA. The
moon is red until it gets above the smog. Well, that is if you're not
*IN* the smog.

Re:Bruce Almighty flashback (1)

MythMoth (73648) | more than 9 years ago | (#12905693)

That's what I thought, until someone pointed out to me that the illusion goes away when you stand on your head.

Guaranteed to make you look foolish, but it works.

Re:Bruce Almighty flashback (4, Interesting)

nofx_3 (40519) | more than 9 years ago | (#12905877)

So what you are saying is that this "Moon Illusion" is simply an occipital lobe processing error? Makes sense to me, there are obviously intances where our brain is incapable of properly processing information. This [michaelbach.de] was the first hit on google. I recommend trying the full tour, its neat stuff.

-kaplanfx

Re:Bruce Almighty flashback (2, Interesting)

dillon_rinker (17944) | more than 9 years ago | (#12905948)

the illusion goes away when you stand on your head

And the perception of depth goes away if you close one eye. And the appearance of continuous motion vanishes if you blink your eyes rapidly. In other words, if you literally change the way you are looking at the world, you will change the way your nervous system processes the light that enters your eye. Your example is intriguing, but not all that revealing.

I won't hypothesize why what you said works (since I haven't tested it), but I will point out that there's more to perception than thinking "That is a tree. That is a bird. The bird is in the tree. Therefore the bird is smaller than the tree. There is the moon..." Vision processing occurs in the retina and the optic nerve and on who knkows how many levels in the brain before conscious thought ever gets involved. Inverting an image completely alters its appearance; is it to much to suppose that the processing of rarely inverted images would be different from the processing of normally upright images?

Completely off-topic I once read that intelligence was nothing more than an overgrown hack on the optic nerve. I partly believe it. The optic centers of the brain imporant bits of the visual signals - there's some lines, there's some blue, there's some motion. Intelligence is little more than astract abstractions - feeding the abstractions back into the engine that produced the abstractions, mixing the levels of abstraction, and seeing what useful behaviors the whole process produces.

Re:Bruce Almighty flashback (3, Informative)

Laivincolmo (778355) | more than 9 years ago | (#12905716)

I've heard however that the illusion even occurs while flying high in an airplane. A horizon of clouds really doesn't give much of a landmark to compare to.

Internal representation of the sky. (3, Informative)

Joe Random (777564) | more than 9 years ago | (#12905776)

The way I've heard it, humans subconsciously model the sky as a flattened dome. Thus, when presented with two objects of equal apparent size, one on the horizon and one at the zenith, the one on the horizon looks bigger (i.e. is perceived as having a larger actual size) because it's "farther away" than, yet appears to be just as big as, the object that is directly overhead (and thus "closer").

Re:Bruce Almighty flashback (0)

Anonymous Coward | more than 9 years ago | (#12905735)

The red light isn't pollution. You're looking at a moonset. It's a sunset, but dimmer.

Take a photo of the moon on the horizon, then take another when it's high in the sky. Measure the moons with a ruler. The horizon one will be bigger. It's not an optical illusion.

Re:Bruce Almighty flashback (1)

JWSmythe (446288) | more than 9 years ago | (#12905809)


> The red light isn't pollution. You're looking at a moonset. It's a sunset, but dimmer.

Hmmmm..

When I lived in the lands far away, where they sky was clear of impurities, the moon would rise white.

When I moved to the land of {{COUGH}}{{COUGH}} pollution, the moon rises many colors.

For the last few days, it's been a nasty sickly red. It's the pollution. I've watched it rise over the smog.

Unless, you're simply saying that the moon isn't really colored red, that it's my perspective through the atmosphere, which is correct. :)

The pollution is still nasty. It's even eerier after the moon is a couple hours up, because you can see the haze over the city under the full moon light. I feel like I should be wearing some sort of air filter to go into the valley.

Re:Bruce Almighty flashback (2, Interesting)

Council (514577) | more than 9 years ago | (#12905914)

The hell, it will be bigger? I predict you are wrong, but will try it out. Though I'll just measure the angle it makes in the sky using my arm and some object (a penny, my thumbnail) for reference.

Speaking of thumbnails, a really good trick for estimating distances if you can estimate object size:

Measure the width of your thumbnail. Measure the distance between your thumb and your eye (arm extended, hitchhiker). Divide the thumb-eye distance by the thumbnail width. You'll get a number around 30.

To estimate distances, stretch out your arm and estimate the height of your thumbnail against an object at that distance. If there's a person standing on a boat, and my thumb is slightly wider larger than their height, my thumb is about 2 meters high. Times 30 puts them at 60 meters away. Best distance estimation trick I know, and great for the compulsive quantiphiles among us.

Re:Bruce Almighty flashback (5, Interesting)

toddbu (748790) | more than 9 years ago | (#12905760)

There's a similar illusion with mountains. When I look at Mount Rainier between some large trees, it looks huge. When I look at it while driving down the highway, it doesn't look all that big. I actually find it disappointing to stand at the foot of the mountain. From that vantage point, it doesn't look all that impressive. Having climbed Mount St. Helens, looking down on a mountain from the top, it looks huge. It's really weird.

Re:Bruce Almighty flashback (1)

Ungrounded Lightning (62228) | more than 9 years ago | (#12905792)

Near the ground, I consider it in proportion to the objects around it. In the sky, I have no reference

Near the ground you compare it to objects on the horizon. Some of those objects are things you have experience with up close (like buildings, trees, and mountains). So you get a sense of scale. The moon appears to be just behind the horizon, making it gigantic (though nowhere as big as it really is).

Far from the ground you compare it to other flying objects that you also occasionally see on the ground or at known distances (i.e. birds) and thus can use for a reference. It appears to be at or just beyond birdflight altitude, which makes it appear much smaller (though it subtends the same angle).

Same illusion happens with the sun, of course. But it's usually not quite as pronounced - because it's more difficult to look directly at it and compare it to objects on the horizon. The "Oh, GOSH it's BIG!" phenomenon happens when the moon or sun and the objects near its postion on the horizon are visible simultaneously, and that happens more often and more clearly with the moon.

It also happens with traffic lights, which are much larger than they appear when they're hanging over an intersection.

So what's the big mystery?

Re:Bruce Almighty flashback (0)

Anonymous Coward | more than 9 years ago | (#12905798)

I've noticed a trend. Those you subscribe to Slashdot (ie. have an asterisk next to their username) are either, (1) arrogant, (2) Republicans, (3) Microsoft shills, or (4) plain old arseholes.

The parent to this post is a worrying combination of observations one and four.

I'm being serious. The only conclusion I can come to is that people subscribe to Slashdot simply to camouflage their agenda and to bestow upon their posts an illusion of credibility.

I'm prepared to admit that observations one and four are opinions but if anyone can point out to me any Slashdot subscribers who don't fall into any of the listed categories, I'll resist posting again on this matter.

Re:Bruce Almighty flashback (1)

letxa2000 (215841) | more than 9 years ago | (#12905833)

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

Huh? What in the world does "this low in the sky" mean? Can it get any lower than "right on the horizon?" That happens each and every day/night and when it's sitting right on the horizon, it's no lower or higher than when it was sitting right on the horizon every day since 1987.

And you can measure the moon and see it's the same size when it's right on the horizon as when it's high in the sky, so how do they come off saying that it's "lower" (or larger) than at any point since June 1987?

In short, what in the world are they talking about???

PS--To be fair, we saw the moon coming up last night over some local mountains and both my wife and I said "Whoaa." The color and apparent size were quite striking. But neither of us went off writing articles saying the moon was bigger than any time in the last 18 years.

Re:Bruce Almighty flashback (1)

GlassUser (190787) | more than 9 years ago | (#12905882)

Huh? What in the world does "this low in the sky" mean? Can it get any lower than "right on the horizon?" That happens each and every day/night and when it's sitting right on the horizon, it's no lower or higher than when it was sitting right on the horizon every day since 1987

They mean a full moon, I believe. Something about it coinciding with sunset on the past couple of days. I'm not sure of the specifics though.

Re:Bruce Almighty flashback (1)

willpall (632050) | more than 9 years ago | (#12905890)

Actually, the objects of reference would tend to make the far-away object appear smaller. Also, as a sibling poster noted, the illusion dissapears when you stand on your head.

My theory? (And by theory, I mean hypothesis) We perceive the sky to be "farther away" at the horizon and "closer to us" above our heads. And since the moon is "in" this sky, the fact that it is exactly the same size at the horizon as it is above our heads makes it appear that it is larger at the horizon because we perceive the sky there to be farther away.

Well.. (0)

slavemowgli (585321) | more than 9 years ago | (#12905683)

The logical conclusion obviously is that the moon *is* bigger when it's closer to the horizon. :)

logic schmogic (1)

handy_vandal (606174) | more than 9 years ago | (#12905742)

The logical conclusion obviously is that the moon *is* bigger when it's closer to the horizon. :)

No, that's the illogical conclusion ... making it more likely to be right.

-kgj

"Logic is a bouquet of pretty flowers that smell bad."
- Spock

Re:logic schmogic (1)

davidj0228 (543196) | more than 9 years ago | (#12905830)

ever heard of Occam' Razor?

You've got it wrong... (1)

exp(pi*sqrt(163)) (613870) | more than 9 years ago | (#12905826)

...it merely looks smaller when it's high in the sky.

I didn't think this was a big mystery. (2, Informative)

shawn(at)fsu (447153) | more than 9 years ago | (#12905685)

I heard on various shows that it's because it's closer to things that our mind knows are big when it's close to teh horizon, trees buildings towers etc. When it's high in the sky there is nothing around it.
Some one on some show said that if you bend over doubled and look through your legs at the moon, no matter where it is in the sky it will appear large as well for the same reason

you mean... (4, Funny)

circletimessquare (444983) | more than 9 years ago | (#12905728)

if you moon the moon there will be more moon?

Re:I didn't think this was a big mystery. (1)

Valiss (463641) | more than 9 years ago | (#12905733)

Some one on some show said that if you bend over doubled and look through your legs at the moon, no matter where it is in the sky it will appear large as well for the same reason


That's just silly. It's an obvious ploy to get people to look stupid.

Now I have to try it. Damn youse!

Re:I didn't think this was a big mystery. (2, Funny)

gardyloo (512791) | more than 9 years ago | (#12905769)

Some one on some show said that if you bend over doubled and look through your legs at the moon, no matter where it is in the sky it will appear large as well for the same reason

Dude, you're just begging to have someone mention that you're comparing the moon to your crotch. But I'll let someone else handle that (as it were).

Re:I didn't think this was a big mystery. (4, Funny)

clem (5683) | more than 9 years ago | (#12905819)

Some one on some show said that if you bend over doubled and look through your legs at the moon, no matter where it is in the sky it will appear large as well

That's no moon.

Re:I didn't think this was a big mystery. (1)

J. T. MacLeod (111094) | more than 9 years ago | (#12905845)

Well, the real test is this:
Hold up your thumb and cover the image of the moon. Most nights, it's easy.

However, some nights, especially in summer, when the moon is just over the horizon, it will appear several thumbs wide.

THAT is the illusion being referred to.

Re:I didn't think this was a big mystery. (1)

niko9 (315647) | more than 9 years ago | (#12905886)

Doesn't explain why pilots, who have no ground objetc references, also see the moon as very large at this time.

Re:I didn't think this was a big mystery. (1)

Dr Reducto (665121) | more than 9 years ago | (#12905951)

Goatse man has that angle covered.

Re:I didn't think this was a big mystery. (0)

Anonymous Coward | more than 9 years ago | (#12905960)


This is the very first theory debunked in the article, asshat:

"Sceptics of this theory point to airline pilots who also see the illusion, although they have no ground reference points."

The moon has appeared larger? (4, Funny)

Anonymous Coward | more than 9 years ago | (#12905688)

For the past few nights the moon has appeared larger? Could this open some eyes and increase interest in alternative (Linux, Mac) offerings?

No, NO. (1)

game kid (805301) | more than 9 years ago | (#12905734)

When the moon rains its cheese [wikipedia.org] , then the Windows users will switch.

Side note: nice lift. ;) [slashdot.org]

Re:The moon has appeared larger? (0)

Anonymous Coward | more than 9 years ago | (#12905773)

I for one, welcome our new slashdot troll-inventing overlords.

Not by itself, but (0)

Anonymous Coward | more than 9 years ago | (#12905885)

it has also been determined by the NYT that this moon is covered in spam zombies.

Re:The moon has appeared larger? (1)

mversteege (883906) | more than 9 years ago | (#12905919)

Remember, VCPR is an advertising free zone, much like the moon, or Time Square.

life (-1, Troll)

Anonymous Coward | more than 9 years ago | (#12905689)

it's Friday, get a fucking life

Re:life (-1, Offtopic)

TripMaster Monkey (862126) | more than 9 years ago | (#12905915)


Definition of irony:
Someone posting on Slashdot on a Friday night, informing other Slashdotters that it is Friday night, and they should 'get a fucking life'.

Priceless.

Oh please (1)

molrak (541582) | more than 9 years ago | (#12905690)

Everyone knows the moon does that because it's made of cheese.

That's some moon. (1)

centauri (217890) | more than 9 years ago | (#12905692)

Too bad Princess Leia is away on that diplomatic mission and can't be here to see this.

Re:That's some moon. (1)

tverbeek (457094) | more than 9 years ago | (#12905726)

That's no moon...

Re:That's some moon. (1)

On Lawn (1073) | more than 9 years ago | (#12905754)


The more Star Wars allusions you make, the more moderation will slip through your fingers.

Re:That's some moon. (3, Funny)

mugnyte (203225) | more than 9 years ago | (#12905860)


Any attack made by you against this post would be a useless gesture, no matter what technical data you have obtained. This post is now the ultimate power in the universe. I suggest we use it.

Re:That's some moon. (0)

Anonymous Coward | more than 9 years ago | (#12905887)

The power to flog a joke to death is insignificant next to the power of the Force.

Easy Fix (4, Funny)

Laivincolmo (778355) | more than 9 years ago | (#12905698)

If you bend over with your head between your legs and look at the moon upside down, the illusion disappears. (I'm being serious too!)

Re:Easy Fix (3, Funny)

Lattitude (123015) | more than 9 years ago | (#12905889)

When you're in that position, it's important to look at the correct moon...

Illusion (1)

CriminalNerd (882826) | more than 9 years ago | (#12905699)

I'd say the reason is because of how the light bends in the atmosphere, or something like that. I thought "experts" would know better than we do. Or at least figure it out faster. =/

Re:Illusion (0)

Anonymous Coward | more than 9 years ago | (#12905744)

No, RTFA, dumbass. If the affect was caused by the atmosphere bending the light, then not only would the Moon subjectively appear bigger, but also, when you measured it, it would actually be bigger. Instead, it can be easily verified to be almost exactly .5 deg in diameter, as always.

The article in its entirety (0)

Anonymous Coward | more than 9 years ago | (#12905704)

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.

Can the Moon Illusion be explained? Here are two theories
In graphics Two main theories dominate. The first, known as the Ponzo Illusion - named after Mario Ponzo who demonstrated it in 1913 - suggests that the mind judges the size of an object based on its background.
Ponzo drew two identical bars across a picture of railway tracks which converge as they recede into the distance (see pop-up, right). The upper bar looks wider because it appears to span the rails, as opposed to the lower bar, which sits between the rails.
In the same way, with a low-lying moon the trees and houses, which are familiar foreground reference points, appear smaller against the moon, which appears bigger than it really is.
Sceptics of this theory point to airline pilots who also see the illusion, although they have no ground reference points.
Alternatively, there's the theory that the brain perceives the sky as a flattened dome rather than the true hemisphere it really is.
Try for yourself
The theory runs that we believe things immediately overhead, flying birds for example, are closer than birds on the horizon. When the moon is on the horizon, the brain therefore miscalculates its true size and distance.
Then there are those who scoff that this is an illusion at all. They, at least, can be proved wrong. Hold a coin up to a low-lying moon to and compare differences in size. Any difference will remain exactly the same, as one traces the trajectory of the moon through the night.
Indeed, it's said that by viewing a low moon though a rolled up piece of paper, to block out the surroundings, the illusion immediately vanishes.
But experts have yet to agree on either or, indeed, any explanation. For the moment at least, the real reason for the Moon Illusion remains up in the air.

Perception of distance and perspective (2, Insightful)

Sv-Manowar (772313) | more than 9 years ago | (#12905708)

It's amazing how much of how our brains and sight work together to recognize object's size and position creates these kinds of illusions. It just shows that even a finely tuned system that works well in everyday use can be caught out, and how because we rely on our vision to give us the absolute truth, its shocking when something manages to fool that sense.

Wait a minute.... (5, Funny)

Joe Random (777564) | more than 9 years ago | (#12905710)

That's no moon!

it's all because (0)

Anonymous Coward | more than 9 years ago | (#12905722)

Bush, Cheney, etc... the fix is in!

PONZO (0, Redundant)

fonos (847221) | more than 9 years ago | (#12905724)

It's called the Ponzo effect. The surrounding horizon makes the moon seem larger but it really isn't.

Re:PONZO (1)

DoorFrame (22108) | more than 9 years ago | (#12905835)

But how is this related to the Ponzi Scheme?

Penis Size? (0)

Anonymous Coward | more than 9 years ago | (#12905861)

So what object can i place next to my penis to make it look larger than it actually is? Those pills from the interweb just aren't working for me.

Re:PONZO (0)

Anonymous Coward | more than 9 years ago | (#12905874)

ok, that's named the illusion. and described it. well done. perhaps you'd now like to explain it - why does the horizon make the moon look larger?

why does the illusion change when you stand on your head, or lie down even?

I think this is an illusion that can't be explained the way many others can, in terms of our increasing understanding of the visual system. a cirle by a line doesn't look larger than a circle a long way from a line, so why should the moon? it's clearly something very complex going on, and only works for the moon (altyhough it works to a lesser degree for the sun) because of its special place in our psyche.

Explained? RTFA? (4, Insightful)

StaticLimit (26017) | more than 9 years ago | (#12905732)

So the title of the submission is: Low-Hanging Moon Explained... and the text of the submission itself says "There is still no agreed on explaination for why the moon appears bigger".

Who writes these titles? Do they even read the submission, let alone the article... (extra scorn if the submitter wrote the title)

Wacky. And I read the article too (before it got posted here). There's definitely no explanation... a couple theories, sure, but they debunk the theories right in the article.

- StaticLimit

As Robin Williams said: (5, Funny)

mcSey921 (230169) | more than 9 years ago | (#12905739)

The moon, like a testicle, hangs low in the night sky.

There goes the karma.

Umm... maybe because a thicker atmosphere? (4, Interesting)

HighOrbit (631451) | more than 9 years ago | (#12905768)

Perhaps when it is closer to the horizon, your line-of-sight to the moon also follows closer to the surface of the Earth. Because the atmosphere is denser at the surface, the denser atmophere has a greater lens effect?

No? Well, it was just a shot-from-the-hip thought.

Re:Umm... maybe because a thicker atmosphere? (1)

ahsect8 (880135) | more than 9 years ago | (#12905853)

The moon is not actually larger. TFA mentions you can always obscure the moon with a dime held at a constant distance from your eye. If there was a lense effect, the magnification would not be illusory.

Re:Umm... maybe because a thicker atmosphere? (0)

Anonymous Coward | more than 9 years ago | (#12905855)

Your missing the point. It really is not bigger. If you hold a dime up in front of your face to make it match the moons size and do the same thing when its high in the sky, it will be the same. It's *image* is the same size. It's an optical allusion.

Re:Umm... maybe because a thicker atmosphere? (1)

sneakers563 (759525) | more than 9 years ago | (#12905859)

Because the atmosphere is denser at the surface, the denser atmophere has a greater lens effect?

Nope, if you take a picture of the "large" moon at the horizon, and then take a picture of the "small" moon directly overhead with the same settings, they're exactly the same size on the image/photo.

Explained? (2, Interesting)

RedWizzard (192002) | more than 9 years ago | (#12905788)

I read TFA and didn't see any explanation. They described the two leading theories, but no conclusion was drawn. The end of TFA leaves it wide open: "For the moment at least, the real reason for the Moon Illusion remains up in the air. "

I'd really like to see a bit more attention paid to making Slashdot headlines accurate, both by submitters and editors.

Isn't it just because of the frame of reference? (2, Interesting)

DoorFrame (22108) | more than 9 years ago | (#12905789)

I thought the moon appeared larger while on the horizon because suddenly the moon appears to be right next to objects whose size we can comprehend. In the middle of a night sky, the mooon is just a circle of light in a giant black space, on the horizon the moon is much much larger than buildings we know to be enormous. Even if against nothing more than the horizon, it still seems bigger because at least it's next to SOMETHING.

Bah... (4, Funny)

NeuroManson (214835) | more than 9 years ago | (#12905790)

Everyone knows that cameras add an extra 200,000 tons.

I doubt that. (1)

game kid (805301) | more than 9 years ago | (#12905836)

The moon is just blossoming in puberty. When it shrinks in size again, the tabloids will wonder what drugs it's been absorbing.

Take a picture (1)

Miamisky (680264) | more than 9 years ago | (#12905796)

Simple enough, if it appears larger to you at the horizon, take a picture, and then take another one when it's higher. Cameras don't have brains.

Re:Take a picture (0)

Anonymous Coward | more than 9 years ago | (#12905939)

and what in the name of all that's holy is the point of that?

no-one actually believes it is bigger - that's why it's called an illusion. the interesting thing is it looks bigger. cameras do not have brains that's true, and the jury's still out on your case.

Is that really a picture of Einstien there? (1)

HoodCrowd (783572) | more than 9 years ago | (#12905799)

Noooooooooooooooooooooooo........ech, ehh, ehhhh.......ooooooooooooooooooo!!!!!!!!!!!!!!!!!!! !

Zonk's on a roll (1)

Buttercup (22814) | more than 9 years ago | (#12905811)

The title says "... explained" and the abstract says "there is no agreed-upon explanation". Read the frigging article, it's a fluff piece saying nobody really knows what accounts for the illusion.

Fucking idiot.

not just the moon (1)

at10u8 (179705) | more than 9 years ago | (#12905813)

The illusion extends to constellations as well. Take a look at a constellation when it is up high and it seems smaller than when it is near the horizon.

Bad science. (0)

Anonymous Coward | more than 9 years ago | (#12905820)

Actually more like brutally retarded "science" in the article:

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

I wasn't aware that the moon hasn't set risen or set since 1987. Apparently the moon has stopped moving relative to the Earth.

More detailed cluestick beating: For most points on the surface of the earth, the moon rose and set again at some point within the last ~24 hours as the Earth rotated. Going below the visible horizon is pretty damn "low in the sky".

Must be Friday (1)

hawkfish (8978) | more than 9 years ago | (#12905821)

And the editors have no dates. So they see the phrase "Low-Hanging Moon" and it sort of eats their brains.

huh? (1)

itzdandy (183397) | more than 9 years ago | (#12905823)

{ -There is still no agreed on explaination for why -the moon appears bigger when it's on the horizon -than when it's high in the night sky." }

first, i did not read every post so excuse this if it has been addressed.

is the earth round? is the atmosphere also round? so if a nearly clear object is bent does it not act as a lense? so if the atmosphere is between the viewer and the moon, wouldn't it bend light the same as a lense? so now tilt the top of the lense towards the viewer just like the atmosphere is tilted from the viewers point of view. doesn't it make the image larger? so..

{ -There is still no agreed on explaination for why -the moon appears bigger when it's on the horizon -than when it's high in the night sky." }

..is complete crap? wtf?

Re:huh? (1)

sneakers563 (759525) | more than 9 years ago | (#12905884)

..is complete crap? wtf?

Well, you could read TFA where it says "Then there are those who scoff that this is an illusion at all. They, at least, can be proved wrong. Hold a coin up to a low-lying moon to and compare differences in size. Any difference will remain exactly the same, as one traces the trajectory of the moon through the night."

It is not larger.

"There is still no agreed on explaination..." (1)

Knetzar (698216) | more than 9 years ago | (#12905824)

I love how many people say that the answer is obvious, but they don't agree with the other obvious answers that are listed.

The math (4, Funny)

MindPrison (864299) | more than 9 years ago | (#12905829)

The more you drink...

...the bigger it will seem

20 % alcohol = 20 Bigger moon 40 & alcohol = thats one BIG moon 90 & alcohol = the size of the moon is no longer a concern of yours. You're somewhere else.

Perspective (1)

SoCalEd (842421) | more than 9 years ago | (#12905842)

Although it makes some sense that the moon appears larger when its near the horizon due to having nearby points of reference to compare it with, this still doesn't explain why on some nights it appears larger than on other nights from precisely the same vantage point. Odd indeed.

Just as long as it stays... (0)

Anonymous Coward | more than 9 years ago | (#12905857)

up in the sky long enough for me to enjoy the Festival of Time that'll be happing in 3 short days.

a joke from my mother: (2, Funny)

zenneth (767572) | more than 9 years ago | (#12905865)


A blond newlywed was enjoying her honeymoon by staring at the night sky from a Hawaiian mountaintop with her newly betrothed. At one point he asked her which is closer, Texas or the moon.

She thought about it for a moment and then her eyes glittered with a knowing look.

She glanced around dramatically and replied, "Duuuh! Do you *see* Texas?"

-
This joke is intended as humor, no offense to any blondes out there, real or implied.

No blondes were harmed during the creation of this joke.

Mod me whatevever.. (1)

sinner0423 (687266) | more than 9 years ago | (#12905873)

I live in a light polluted town (Aurora, IL) so I barely get to see anything besides an ominous orange glow in the sky at night.

But these past few nights I've just been sitting out watching the moon for a few hours at a time, and it really is something to look at if you haven't done so already. I know late night is prime geek computing time, but go outside for 5 minutes and check it out.

This is no mystery, its an optical illusion. (2, Informative)

kevlar (13509) | more than 9 years ago | (#12905880)

The Moon doesn't change sizes (that the human eye can ascertain at least) and it is not magnified by the atmosphere on the horizon. It is merely an optical illusion.

When the Moon is close to the horizon your brain compares its size with terrestrial objects. When its at its zenith, the brain does not. We only perceive it as being larger on the horizon, when in fact our brains are just misjudging its size.

NASA scientists don't know this? Bullshit alert!

Easy way to tell a poster doesn't wear glasses (1)

WillAffleckUW (858324) | more than 9 years ago | (#12905893)

when they post news stories about optical illusions instead of the bending of light due to the refractive index of the atmosphere.

Once in a Blue Moon (volcanic eruptions, forest fires, burning crops), they remember there's a Red Moon (ditto, more active, different light levels), and then decide to just post about the difference between a Lunar Eclipse and a Solar Eclipse.

Explaination (0)

Anonymous Coward | more than 9 years ago | (#12905905)

There is still no agreed on explaination

There's apparently still no agreed upon way to spell explanation, either.

A simple test of the moons size... (1)

stefanlasiewski (63134) | more than 9 years ago | (#12905908)

Here's a simple test to convince most people that the moon is the same size near the horizon then it is in the middle of the sky.

When the moon rises, extend your arm all the way, hold your thumb next to the moon and take an approximate measurement of the moon against your thumbnail. You just need an approximation.

A few hours later, when the moon is higher in the sky, do the same thing.

This seems to be enough to convince most people that the moon is about the same size.

Of course, then you have to deal with the people who think that their thumb strinks as the night gets later, but I can't help you there.

Other moon phenomena. (1)

ChickenFan (887311) | more than 9 years ago | (#12905931)

The moon size illusion is interesting, but a lesser documented moon phenomena is this:

If you stare at a full moon long enough, you'll develop an irresistable urge to pee.

"Low-hanging" moon? (5, Insightful)

Kelson (129150) | more than 9 years ago | (#12905950)

Not since June 1987 has the moon been this low in the sky

Umm... how about twice a day, when it rises and sets?

Who writes this crap?

guns & roses (0)

Anonymous Coward | more than 9 years ago | (#12905956)

the moon is inpired by
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