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Low-Hanging Moon Explained
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."
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.
____
~ |rip/\/\aster /\/\onkey
Duh! Because it's closer!
some guy who got gods powers is trying to get laid... apparently its taking longer than the last guy i saw try this one.
There's nothing Intelligent about Intelligent Design.
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.
Serious? Seriousness is well above my pay grade.
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
500 dollar reward for tip(s) leading to the arrest of the person(s) who stole my sig.
For the past few nights the moon has appeared larger? Could this open some eyes and increase interest in alternative (Linux, Mac) offerings?
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!)
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.
Business Voyeur
That's no moon!
if you moon the moon there will be more moon?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
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
The moon, like a testicle, hangs low in the night sky.
There goes the karma.
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.
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").
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.
-- Boycott Shell
I'd really like to see a bit more attention paid to making Slashdot headlines accurate, both by submitters and editors.
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.
--
RumorsDaily
Everyone knows that cameras add an extra 200,000 tons.
Just because you can mod me down, doesn't mean you're right. Shoes for industry!
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.
What this world is coming to - is for you and me to decide.
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.
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.
The Chronic *WHAT* les of Narnia!
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!
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?
In March 1999, Sky and Telescope magazine published an article about Blue Moons by Philip Hiscock, who has studied the folklore and history of the expression. In that article, Hiscock traced the many meanings of the expression over the centuries, but noted that the "two Full moons in a single month" meaning couldn't be explained satisfactorily.
In the May 1999 issue of Sky and Telescope, there appeared a follow-up article which proved that Sky and Telescope had in fact created the current meaning by mistake in an article published in March 1946. The author of the 1946 article had misinterpreted a page of the 1937 Maine Farmers' Almanac.
By studying copies of the Maine Farmers' Almanac dating as far back as 1819, the authors of the May 1999 article showed that the compilers of the Almanac used the term to label the third Full Moon in a season which has four.
We have calculated the dates of this type of Blue Moon for the 20th and 21st centuries and put them in a list for you to browse.
It's a delightful irony that Sky and Telescope, in publishing an article in March 1999 on the history and folklore of Blue Moons, should turn out to be celebrating a "tradition" which it inadvertently created in an article 53 years before!
So which definition is "correct"? The authors of the May 1999 article admit,
With two decades of popular usage behind it, the second-full-Moon-in-a-month (mis)interpretation is like a genie that can't be forced back into its bottle.
And Charles A. Federer, Jr., the founder of Sky and Telescope magazine, adds,
Even if the calendrical meaning is new, I don't see any harm in it. It's something fun to talk about, and it helps attract people to astronomy.
http://www.obliquity.com/astro/seasonal.html
The answer is that it is an optical illusion of your brain, the moon doesn't change.
To test this, go outside at noon (when the sun is highest and 'smallest'), take a penny, close one eye, and hold the penny out towards the sun so that it perfectly blocks the sun. Note how far away the penny is from your eye.
Now go out at sunset when the sun is low on the horizon and seems huge. Again take the penny and hold it out to where it perfectly blocks the sun. You will notice that you are holding the penny at the exact same distance from your eye, meaning the size of the sun is exactly the same, you just perceive it to be huge.
This is a natural adaptation of our brain, allowing us to deal with distance. For example, if you see a huge tower far away in the distance, you know that it is huge, even though in actuality it is very small from being so far away, much smaller than something close to you (like a tree or a house).
What happens with a sun/moon that is low on the horizon is this unintended side effect of our brains dealing with distance. Because it is low on the horizon and is so far away, you perceive it as being huge, when in fact it is the exact same size as when it is overhead.
it's bug in Matrix. A 2D transform/rendering artefact. Ever noticed a simple static texture for moon, with a black circle occlusion blended, no animation at all?
There you are, staring at me again.
Well, if you're patient you can prove to yourself it isn't any bigger without standing on your head.
The moon subtends about 2 solid degrees. By fortunate coincidence, this is more or less the same angle subtended by by most adult's fingers when their hand is held at arms length -- very rought it's true, but close enough.
So, just hold your index finger at arms length. It will be wide enough, approximately, to just cover the moon. Remember how it looked. Then look for the moon later when it's higher in the sky and try again. The moon looks much smaller in all that empty sky, but it will be about the same size compared to your finger.
The finger trick is useful for rough angle estimations. A hand width with closed fingers is about ten degrees, and a spread fingered hand (unless you have Marfan's syndrome) is about twenty. If you are really concerned about accuracy, you could calibrate it I suppose and multiply by some factor other than 2 degrees per finger width. I wouldn't use it for civil engineering purposes, but it will do for navigation and star hopping.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
My high-school science teacher Dad explained this to me when I was about 6 years old.. How is it that these 'great minds' of the world have been grappling with this for so many centuries?
It's refraction... The same reason it's very difficult to catch fish with a spear or bare-handed..
When you look at the water in a stream at an angle, you're not seeing 'in a straight line', the refraction due to the surface of the water causes you to perceive the fish in a different spot than it really is.
This can also be observed in a fish tank (get real, this is Slashdot, do any of us EVER find ourselves wading in fish-bearing streams?) If you look at the tank from the outside, straight-on, you see the fish where it really is. If you look from an angle, however, your perceprion of where the fish is will be distorted in proportion to the angle at which you deviate from the perpendicular (with respect to the side of the tank)
If the surface of the tank were curved (like the atmosphere) you'd perceive the fish to be larger than it is as well.
In the moon's case, if you are looking straight up at the moon when it is directly overhead, you're experiencing as little atmospheric/curvature distortion as possible. As the moon gets lower in the sky, the refraction becomes more pronounced resulting in the perception of a larger moon...
I dub this the Archibald Castell Jr. (Dad) theory of moon illusion.
I assume I'll be contacted by the Nobel people soon...
The Straight Dope answered this one 10 years ago: Why does the moon appear bigger near the horizon?
1) Nobody with even a passing knowledge of science spells "lense" with an "e" at the end.
2) The gravitational field of the Earth does not produce a lens effect. A gravitational lens occurs when light from behind an object is focused by the entire circumference of the object:whereas any "natural lens effect" by the Earth for Earth-dwellers would only bend the light, not focus it. Not to mention that this gravitational field is too weak to make a noticeable difference. That's why the experimental confirmation of the bending of light (after Einstein's prediction) had to wait for a solar eclipse, and couldn't be confirmed with Earth's gravity.
3) The angular diameter of the image of the moon (the light rays reflected from it) is equal when the moon is low and when it is high. It's an optical illusion, not a concrete fact. It also works with the Sun, which may be easier to measure. Take a picture of a sunrise or sunset, when the Sun appears large. Take a picture of the Sun in the sky, when it seems smaller. The disc of the Sun will have the same size in both pictures.
4) What the heck does the linked article have to do with the moon?
But I think he means that in a different way, your brain knows the horizon is far away, but has no idea how far up the moon actually is because you've never been up there.
It's about a distance frame of reference, not a size frame of reference.
*.sig
Basically, what this means is that the moon is the correct size on the horizon, and this "bug" causes it to look too small when it is high in the sky.
I would like to propose a hypothesis why this is actually not a "bug" but has a purpose: gravity and hand-to-eye-coordination.
Most of us may have noticed that when you throw things, the things won't keep going straight to that direction, but fall to ground. We are pretty good at throwing at things far away rather accurately. You don't need to calculate the "launch parameters" mathematically, but you just look at the target and your brain "just does it".
Now, if something is 20 meters up above, you need to throw a lot harder than when it's 20 meters away horizontally. Therefore, your brain makes it look like it's farther away to compensate. This may be a bit indirect way of compensating, but that's often how the nature works.
Just a 2.4132 cents worth from your AI guy.