This is what you get if you take a photo of the Moon every night for a month, then make a movie out of those pictures. The Moon’s phases aren’t surprising, but the Moon also appears to grow and shrink as it orbits the Earth. This happens because the Moon’s orbit is slightly elliptical; its distance to the Earth varies by about 10%.
Also, the Moon appears to “wobble” from left to right. That’s because the Earth’s gravity pulls harder on the Moon the closer it is to the Earth, so the Moon travels faster in its orbit when it’s closer to the Earth. The Moon’s rotation rate matches its average orbital speed (which is why we only see one face of the Moon), but its orbital speed varies during the orbit while its rotation rate remains fixed, so the Moon appears to wobble from left to right.
2009-08-10 Update: I’ve noticed that many people arrive at this article by googling moon wobbles. All the other sites on the first page claim that “moon wobbles” are responsible for explosions, mass-murder, earthquakes, terrorism, etc. Sadly, I need to emphasize that the wobbling I’m describing can’t possibly result in these kinds of ludicrous effects.
Last modified January 17th, 2010
Also, if you look carefully, you’ll notice a slight up-down wobble as well.
The origin of this wobble is totally different: it’s caused by the fact that the Moon’s axis of rotation isn’t quite perpendicular to the line that connects the Earth and the Moon.
In other words, the Moon wobbles up and down for the same reason that the Earth experiences seasons.
Interesting, it doesn’t surprise me that the moon wobbles to a certain extent. The 10% part surprised me, larger than I would’ve thought.
Beautiful visual. I’m thrilled to see this. Thanks for sharing.
Have you ever researched why the moon looks so much larger at certain times of the year? For example, the harvest moon seems very much larger than a typical moon. I’ve always wanted to stop and figure this out but I’ve been just simply too lazy.
I can’t claim credit for the image, it’s from here.
I think you’re referring to the moon illusion where the moon appears larger and closer when it’s near the horizon rather than directly overhead. It’s probably a quirk of human vision rather than an inherent property of the moon’s orbit. I say this because the moon’s angular size is actually slightly larger when it’s directly overhead than when it’s on the horizon because we’re 1 earth radius closer to the moon when it’s directly overhead.
There are quite a few hypotheses to explain this illusion, but most of them are inadequate. Here’s a very comprehensive overview where the author argues that “oculomotor micropsia” is responsible.
Nice pic. The “Moon Wobbles” you describe are not the “Moon Wobbles” that mark disaster-prone phases in the world. These other Moon Wobbles were discovered in the 1930’s, when research by astrologer Carl Payne Tobey (1902-1980), the original editor of Astrology Magazine, revealed that disasters occur in cycles associated with the conjunction (0°), opposition (180°) and square (90°) from the Sun to the Moon’s Node. These powerful contacts occur when the Sun and the Node are in the same sign, or the opposing sign, or when the Sun is in a square aspect to the nodal axis. They are especially potent when the New Moon or Full Moon are square to the Nodes.
I gather you are skeptical of the astrological POV, since you use the word “ludicrous” but you should read my article to get a better idea of what is actually being discussed.
Best wishes
Rob Tillett
I’m skeptical of astrology because it’s been repeatedly disproven. It’s certainly not a science.
… A highly unscientific analysis that makes no astrophysical sense and doesn’t even bother to calculate a p-value?
Unless you use rigorous statistical methods, you’ll continue to draw bizarre conclusions from random noise, just like Carl Payne Tobey did.
I think that if you choose not to see you will not see regardlesss of what is real. Science is a religion. So it is limited but do not try and tell that to the limited visioned scientist. And just as science is finally bumping up against religion and the truth is being revealed…there will always be those who refuse to see anything beyond their limited ability. If you cannot concieve of it you cannot see it. And by the way, rigorous statistical methods only prove that the scientist affects the experiment. There is no way of getting around it, we are all connected.
Only in the sense that baldness is a hair color. I’ve previously defined religion and science; they seem completely different. If your definitions differ from mine, please tell me how– explicitly– so I can understand what you’re saying.
There’s no need to tell us, because we already recognize that science is limited.
I’ve noted that science isn’t capable of revealing truth at all. Science is limited to developing models that make unique predictions, which can then be compared to experiment.
How ironic that you write such an anti-scientific sentence on a computer– a device that works based on principles of modern quantum mechanics. Without rigorous experimentation, the flaws of classical physics wouldn’t have been discovered, so semiconductors probably wouldn’t have been invented. If generations of scientists hadn’t poured their lives into understanding the properties of light, the fiber-optic cables that transmitted your words to this website wouldn’t exist.
I can only assume that you didn’t bother to read any of the links I provided in my last comment. They conclusively show that astrologers can’t make predictions that are more accurate than random chance.
The moon and other planets and sun all have a force upon our planet. If the moon can move oceans than it can also slightly move thicker magma both creating massive preasure on our delicate outer crust. Major recorded events of catastrophes coralate with lunar and solar events and that is factual. And if meteor can have such long long orbits around earth and or sun this proves the far reaching effect of gravity. The moon is so massive and so close its effects are enourmous especially when there is a solar eclipse. The gravity is magnified and more concentrated. God says the planets are for a sign and wonders, read!!!!!!!!
Yes, scientists have known about universal gravitation since the time of Newton.
Yes, the moon’s gravity causes body tides where the solid earth is compressed at tidal frequencies. The only reason we notice tides in the ocean is because ocean tides are ~3x larger than body tides; what we actually observe at the beach is the difference between the ocean tide in the water and the body tide of the beach itself.
But this is well established in mainstream science, and has nothing to do with these ridiculous astrology claims.
Solar storms such as coronal mass ejections shorted out telegraph wires in 1859, shut down a Canadian power grid in 1989 and disrupted communications satellites in 1994. The near-complete lack of sun spots during 1645-1715– a period later called the Maunder Minimum– worsened a “Little Ice Age” on Earth.
But, of course, that’s not what these astrologers are talking about. And there aren’t any lunar events that affect Earth aside from eclipses and regular variations in tide heights, all of which are accurately predicted by modern science.
Instead of declaring your statement to be “factual” maybe you should consider providing evidence to back it up.
Not nearly as impressively as observations of galactic superclusters, which show that gravity reaches across billions of light years.
Again, this is irrelevant. Physicists understand very well that gravity has infinite range, which (in many current theories) is a consequence of the graviton having zero rest mass.
No, spring tides are larger whenever the moon is “new” (which means it’s dark, so it’s roughly in between the Sun and Earth.) It doesn’t have to be exactly in between the Sun and the Earth as in the case of a solar eclipse.
For example, spring tides also occur whenever the moon is full (which means it’s entirely lit up, so it’s roughly on the other side of the Earth as the Sun.) That’s because, as I’ve discussed, high tides happen on both sides of the Earth simultaneously.
No. Just… no. Gravity isn’t ever magnified or concentrated. The spring tides I just discussed happen because the gravitational force vectors of the Moon and Sun add constructively, rather than partially canceling as in the case of neap tides.
Maybe I should read all the rigorous, peer-reviewed sources you provided to back up these astrology claims? Oh, wait…