What is with the Moon?

Question

Why sometimes does the moon look like it is at a normal distance away from earth and is white and then the next night it looks very close to earth, it looks HUGE and its an orange color? And this will happen at the same time of night...i drive my sister to work at 10:30 at night and sometimes its little and white and others its huge and orange...Can someone explain this to me?

Answer 1

The lower the moon is in the sky, the closer it is to the horizon, the bigger and more orange it will appear. It has to do with us looking through more atmosphere so the moon becomes 'stretched' due to the amount of water vapor we are looking through. So when its nearer the horizon its larger and colored (due to the amount of dust in the atmosphere) and when its above its smaller and whiter. Same thing with the Sun.

Also, the moon is not in perfect circular orbit with the earth, so some days/months the moon looks larger due to the fact that it is physically closer to us than the day/month before.

I hope this helps and if it does please consider me for those 10 points.

Answer 2

The orange and red tints that the Sun and Moon sometimes take on are caused by the particles in the Earth's atmosphere.

When light (or more specifically, packets of light called photons) from an astronomical object passes through the Earth's atmosphere, it scatters off of particles in the latter. It turns out that these particles like to scatter blue light more than they do red light; so "bluer" photons (those with shorter wavelengths) tend to get scattered, and "redder" photons (those with longer wavelengths) pass through. So, astronomical objects look redder from Earth than they would from space, because the redder wavelengths from the objects penetrate the atmosphere better than the bluer ones. Incidentally, this is why the sky is blue: blue light from the Sun is scattered in all directions on its way to the Earth.

But how does this explain the occasional redness of the Moon or the Sun? Your son may have noticed that they always occur when the Sun or Moon is close to the horizon. If you think about it, sunlight or moonlight must travel through the maximum amount of atmosphere to get to your eyes when the Sun or Moon is on the horizon (remember that that atmosphere is a sphere around the Earth). So, you expect *more* blue light to be scattered from Sunlight or Moonlight when the Sun or Moon is on the horizon than when it is, say, overhead; this makes the object look redder. In other words, the Sun or Moon tends to look orange or red when it is rising or setting because that's the time when the light has to travel through the most atmosphere to get to you. The effect is exacerbated when there are thin clouds in front or behind the Sun or Moon: the clouds themselves often glow bright pink as well, because they are so good at scattering blue light.

The Moon's orbit around Earth isn't a perfect circle - it's actually fairly elliptical - about 5.5% eccentricity. This means there's a fairly large difference between the perigee (when the Moon is at the closest point in its orbit) and apogee (when the Moon is at its farthest). This means that the Earth-Moon distance varies by about 13,000 miles either direction of the average distance. So if the full moon occurs at or near perigee, it appears noticeably larger in the sky than if it occurs at apogee, and it also it is brighter, because the amount of light received by the Earth from the Moon depends not only upon the amount of light the Moon gives off, but also how far the Earth is from the Moon. The farther the Moon, the smaller the fraction of the Moon's light that reaches Earth. I should add, however, that while this is a significant effect, all full moons are large and bright, so it's difficult to tell the difference without being able to look at a perigee and apogee full moon side by side. This year, the lunar perigee occurred only hours from the full moon on April 16th. It was the closest full moon of the year, but not the closest the Moon has been to the Earth in recent times. The nearest perigee recently was in 1912. For a much more detailed explanation, check out this site - it even has a link to a perigee and apogee calculator so if you want to observe this phenomenon you'll know when to take a look!

Answer 3

The amount of atmosphere change the color, but not the size. The distance from the Moon to the Earth doesn't change appreciately during the course of the night, so that's not explaining the size change either.

It's an optical illusion. On the horizen, your eyes have a lot of things to compare the size of the moon to - trees, buildings, etc. Overhead, they don't. It's a little more complicated then that, actually - your eyes percieve the moon as CLOSER overhead, and therefore translate it as smaller, whereas they see it as FURTHER on the horizen and make it look bigger to your eyes. It's a hard one to wrap your head about so - just go with 'optical illusion'. It's not changing size or moving away, it's all in your head.

Answer 4

As you would know the Earth isn't actualy state up and down the globe is tillted so there is always a closer point in the horizon and when the moo approaches the closest point to your position it seems larger (15 degrees over 5cm isn't much but over 30000km it is a huge gap

Answer 5

Moon -- Lots of beauties