On some ocasions i have looked at the moon and have been convinced it looks larger and i can see more detail. Is this a consequence of the lensing effect of ou atmosphere, or sometimes is it flying closer to make it appear so?
2007-12-02 05:01:43 · 14 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Wacko! Answers rides again.
It is NOT caused by lensing of the atmosphere. If it was, it would be measured as larger close to the horizon. Using a small coin, anyone can show that its the same angular size close to the horizon and high in the sky. Those 3 thumbs-ups are a worry.
It is NOT caused by comparison with terrestrial objects.
The moon does have an elliptical orbit, but the change in apparent size is very small. It isn't noticeable from one night to the next.
This is the best explanation we have so far:
http://facstaff.uww.edu/mccreadd/
2007-12-02 09:58:03 · answer #1 · answered by Anonymous · 0⤊ 0⤋
The moon's orbit around the earth is eliptical and sometimes the moon is closer to the earth, and sometimes it is farther. Read all about it here:
http://www.fourmilab.ch/earthview/moon_ap_per.html
John Walker also has some cool astronomy based programs on his web site.
PS: There is an effect that when the moon is low in the sky (risinging, etc.) that the earth's atomsophere can sort of act like a magnifier. Sometimes it looks bigger when it is just rising, but when it rises a little bit, it looks smaller. When it is low on the horizon, the image (the light) passes through more atomosphere (I do wonder if the fact that the atomphere "curves" at that angle comes into play).
2007-12-02 05:09:23 · answer #2 · answered by Damocles 7 · 0⤊ 0⤋
There are two effects.
One is the Moon illusion, where it looks bigger when seen near the horizon. People just perceive things (all things, not just the Moon) on the horizon as bigger than they really are. This is an optical illusion that can be overcome by looking it it upside down.
Another is that the Moon's orbit is elliptical, sometimes coming a little closer than other times. But the difference is small, too small to notice easily, and it is usually the Moon illusion that people talk about.
2007-12-02 05:07:35 · answer #3 · answered by campbelp2002 7 · 2⤊ 0⤋
It is strictly a matter of contrast,it stays virtually the same size all the time.
If you could put a house 20 or 30 miles straight up towards the full moon,the moon would suddenly look much larger when contrasting it with the house.
The greatest contrast is on the prairies where the horizon is clear it look that much larger.
2007-12-02 06:24:27 · answer #4 · answered by Billy Butthead 7 · 0⤊ 0⤋
I would love to know more about Astronomy, but I dont.
But, I do know that the moon has a shorter orbit of the earth (29 days) than the earth has in it's own rotation, which is 30/31 days, This is why you offen see the Moon in the daytime. However, as far as it getting, or seeming, bigger, can only be attributed to (in my limited knowledge) the fact that the earth tilts on a regular basis, hence, giving us our seasons.
Therefore, the Sun certainly does get closer & bigger, but the Moon? I'm not sure
I've never asked a proffessional about this, but I certainly will do now.
Hopefully, I will get my answer here along with you?
2007-12-02 05:39:06 · answer #5 · answered by Anonymous · 0⤊ 0⤋
I know that 2 months ago, the moon was at its closest orbit to the earth and therefore looked 30% larger. I get updates from spaceweather.com. They're very informative.
2007-12-02 05:11:01 · answer #6 · answered by EarthGirl 6 · 0⤊ 0⤋
It's a consequence of the lensing effect of our atmosphere. You'll notice that the lower it is on the horizon the larger it will look.
2007-12-02 05:05:06 · answer #7 · answered by Anonymous · 3⤊ 1⤋
The Moon's orbit is not a circle. It orbits in an ellipse - therefore, when it's at the end of the ellipse, it's further away from Earth than when its at the flattest point of the ellipse.
At its closest, its about 222,000 miles away from this planet. At its furthest away, its around 252,000 miles away. Therefore, you are correct when you say that it appears closer - it IS closer! 30,000 miles closer at the flattest point of the ellipse.
2007-12-02 05:12:15 · answer #8 · answered by Anonymous · 1⤊ 0⤋
Campbel is correct except that it does not appear larger on horizon it appears correct size ... it appears smaller than reality when nothing to compare it to.
Source University Opthalmics department 1968 UK
2007-12-02 06:49:36 · answer #9 · answered by eastanglianuk1951 3 · 0⤊ 0⤋
Yes you are exactly right. At times the moon is closer due to the path of its orbit, but you are correct with your original thoughts.
2007-12-02 05:08:26 · answer #10 · answered by trymilkingme 1 · 1⤊ 0⤋