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Santhosh Mathew, PhD

Santhosh Mathew, PhD

Posted: March 15, 2011 06:46 PM

The Moon Is Not a Harsh Mistress


The speculation that the full moon and its gravitational effect on Earth could trigger earthquakes and other natural disasters is getting attention in some quarters. It is not surprising, given the fact that humans have been looking above rather than below our feet for answers since ancient times.

The coming March 19 is a full moon day, in fact, a special one dubbed as "supermoon. On this day, the Moon will be closer to Earth in its last 18 years -- it's full and close. It will approach the Earth at a distance of 221,567 miles -- a lunar perigee.

The gravitational pull of the Moon on Earth is evident from the ocean tides. Basic science tells us that the tides are caused by the difference in the gravitational force of the Moon across the Earth. Stronger tides near the full moon are nothing unusual. When the Sun, Moon and Earth are along a straight line, as in the case of a full moon, the tidal effects will be increased.

Although the Sun has a larger gravitational influence on Earth, the difference in the Sun's gravitational force between one end of the Earth and the other is not as much as that of the Moon's -- the reason tides are caused mainly by Moon's gravity.

The whole idea that the proximity of moon could affect the Earth seems to have some weight. It is true that Moon's gravity can cause land tides similar to ocean tides. But, this stress can accelerate tectonic activity to cause earthquake is beyond any known science now. We need to know the real science rather than mere coincidences or the statistical flukes.

The recent Japanese earthquake and the upcoming full moon have no correlation at all.The Moon will be at its perigee on March 19th and was actually farther than the average distance on the day the Japanese quake hit.

Scientists have studied the Moon for decades and have found no conclusive evidence to connect the Moon with the seismic activities here on Earth. Being in an elliptical orbit, the Moon's distance varies as it orbits the Earth. It will go through perigees and apogees several times a year. On some of these occasions we may face natural disasters but many other days are just fine. If we insist on finding the correlation between earthly events and celestial phenomena, we could find plenty of them, and there are numerous such incidents in the universe to link even with our everyday activities. No wonder that in the past (perhaps even now) people believed moon can affect our individual moods. Remember the phrase lunatic!

If we are determined to search the root cause of earthquakes, it may be a better idea to look for reasons below the Earth's surface as well. There are inconclusive discussions about the correlation between drilling and the possibility of earthquakes. There could also be several other factors which we don't know yet, natural or man-made, which trigger earthquakes. By all accounts, the Moon seems to be a minor player now.

The Moon's gravitational pull on Earth at lunar perigee is not hugely different from other times, which can be calculated from simple mathematical equations. Even if we consider the effect of the Sun along with that of the noon when they align together, it is not significant enough to alter the internal balance of the Earth. We can reasonably assume that the only change on March 19th would be an apparently bigger Moon and it may offer a special treat for skygazers.

 
The speculation that the full moon and its gravitational effect on Earth could trigger earthquakes and other natural disasters is getting attention in some quarters. It is not surprising, given the fa...
The speculation that the full moon and its gravitational effect on Earth could trigger earthquakes and other natural disasters is getting attention in some quarters. It is not surprising, given the fa...
 
 
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01:07 PM on 03/19/2011
Yay! Heinlein reference!
06:59 AM on 03/17/2011
You are so right when you say "It is not surprising, given the fact that humans have been looking above rather than below our feet for answers since ancient times." More importantly we need to look right "under our noses!" There are many issues we ignore that lead to harmful consequences directly in our line of sight but apparently beyond our capacity to understand. Overpopulation pollution, resource depletion, malnutrition and the list goes on. How wonderful it would be to live in a magical world where moons caused earthquakes and nuclear reactors to meltdown! Then it could be folly. Demons then might be responsible for madness, God's for retributions and superstitions for fortune and misfortune. Maybe we know too much but have learned very little.
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HUFFPOST BLOGGER
Santhosh Mathew, PhD
05:19 AM on 03/17/2011
While the earth and mars would be approximat­ely the same age, Mars is not geological­ly active because it lacks a large dance partner to exert tidal forces on it.

The Martian mantle is too rigid and the crust too thick for plate tectonics to occur. Mars appears to be a planet where such activities started but was stifled by the rapidly cooling outer layers long back. However, Earth’s thin crust is composed of separate solid plates which float on top of the hot mantle.
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Visionary Excellence
02:49 PM on 03/16/2011
Its my understanding that the the earths gravity is inconsistent. http://www.geekosystem.com/hd-gravity-map-earth/

I also understand that there would be gravitation distortions to time and space from many celestial masses, such as the super massive blackhole in the center of the milky way that cycles at 10million years, or all that dark matter and dark energy theyve just discovered. Everything in the universe is in motion too, so those distortions would be in motion.

Is this what is covered in astroseismology? The wiipedia entry only describes the study of the inside of stars.

I would also imagine that extremids might be important too. Whats the relation between tectonic plates and biomass?

Also the magnetosphere, the earths core, cosmic radiation etc.

I'm just a layperson making stuff up, but it seems complex. I wish there was more funding for basic science. Earthquakes suck.
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HUFFPOST BLOGGER
Santhosh Mathew, PhD
05:30 AM on 03/17/2011
The super massive black hole at the galactic center has negligible effect on the solar system.This is about 30,000 light years away.The only important force that acts on the Earth is the gravitation of the Sun and Moon.

Asteroseismology is the the study of Stellar Oscillations .For more information,
http://astro.phys.au.dk/KASC/seismology/seism.html
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Visionary Excellence
12:28 PM on 03/17/2011
Do you have an opinion re double dark theory?

Given that scientists have yet to discover a direct one on one correlation between lunar cycles and seismic activity. Could this be a sign of complexity such as a+b+c phenom. Ive heard that supernova(?) gamma ray spikes from across the galaxy can cause the earth magnetosphere to vibrate. Arent electromagnetic forces stronger than gravitational forces at a sub planetary scale?
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hagagaga
My comments are funnier than yours.
12:30 PM on 03/16/2011
I approve of the title, Heinlein being my favorite author, but when Manuel Garcia-O'Kelly said "Luna is a stern schoolmistress" to the Federated Nations in the book, he was referring to the fact that adapting to the moon and surviving required the Loonies to struggle much more than any Terran.
11:53 AM on 03/16/2011
of course the tidal pull of the moon and sun cause (or at least contribute to) seismic activity. if one merely looks at mars, further from the sun and lacking a sizable moon, there are fewer tidal forces to keep the plates rubbling and jostling against one another and the result is a planet that is much quieter seismologicly speaking.
02:32 PM on 03/16/2011
Are you kidding? Mars is dead geologically, or close to it, because it's small, not because of it's tiny moons. It had a vigorous past though. As evidence of Mars geologically active past look up the Valles Marineris and Olympous Mons: A canyon bigger than 10 grand canyons and the biggest volcano in the solar system.
04:21 PM on 03/16/2011
while the earth and mars would be approximately the same age, mars is not geologically active because it lacks a large dance partner to exert tidal forces on it.
04:25 PM on 03/16/2011
io, one of jupiter's moons is very volcanically active yet it is much smaller than mars
11:55 PM on 03/15/2011
Well, ..I'm going to be one of those fools who rush in where angels fear to tread, and begin by observing that according to David Freedman's book 'Wrong', scientists *do* get it wrong most of the time.

From a geological perspective global deformation does implicate a celestial mechanical cause, for which Moon capture would fit the bill very well. Seems to me that in explaining major earthquakes of the circum-Pacific we could well be witnessing the residual effects of that event.

To advance this however requires dismantling Plate Tectonics. As a theory, PT appeals to many but as a *geological model* (cognisant of the geological evidence) it fails abysmally.

If readers are interested, I run a website on the alternative view, which admits a contribution of the Moon to this devastation, a topical gateway to which in view of the negation in the article above is:- http://users.indigo.net.au/don/nonsense/fraud.html

The effect of the Moon is interactive with the geological condition of the Earth. It is not a unilateral system.

Always acknowledging of course that "Wrong" is a sword that cuts both ways.
10:50 AM on 03/16/2011
This is the part of the Bugs Bunny cartoon where Bugs holds up a sign with a screw and a baseball on it.
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11:17 AM on 03/16/2011
You're too kind.
05:13 PM on 03/18/2011
Chicagoans go through perigees several times a year too. I like the cheese ones myself. Applegees? Is that a special at Applebees?
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Santhosh Mathew, PhD
09:03 PM on 03/15/2011
Please read the last paragraph of post as;

"Even if we consider the effect of the Sun along with that of the Moon when they align together, it is not significant enough to alter the internal balance of the Earth."
08:10 PM on 03/15/2011
Let's assume that there's something spectacular about the gravitational effects of the sun, earth, and moon being aligned and that the moon is closest to the earth at that point.

It doesn't really make any difference as the quake took place a week before that moment when the moon was not in alignment but was, instead, at right-angles to the sun/earth axis.

That means tidal stresses were at their lowest.

Some people don't seem to realize just how quickly the moon moves. It was nowhere near this magical spot when the quake struck. Thus, even if we were to assume that the moon's tidal stresses could trigger earthquakes, it couldn't have been the moon that did it this time.
12:59 PM on 03/16/2011
just because a given seismic event and the maximal tidal forces do not exactly coincide in time does not mean they are not related. suppose that everytime the moon completed an orbit around the earth the pressure at some hypothetical fault line increased by a small amount. the fault may or may not shift when maximal force is applied but when it eventually does one cannot dismiss the tidal forces.

suppose a gun shot victim survives for a month before clearly dying from complications of the injury. the doctors do not shrug and exclude the gun shot because it happened a month before.
04:32 PM on 03/16/2011
Then it would have happened a week before when the sun, moon, and earth were again in alignment. You're trying to have your cake and eat it, too: You want the tidal stresses of the moon to be so great as to be able to cause earthquakes, but you want them to be able to do it when it isn't really pulling that hard because the effects are subtle.

Look, I fully understand the effect that tidal forces can have on a body. It's why Io is wracked with vulcanism: It's orbit around Jupiter puts such large gravitational stresses upon it that it is constantly being churned up and spewing lava.

But that simply isn't the case here. The tidal stresses upon the earth were minimal at the time both due to the alignment of the moon, earth, and sun as well as the fact that the moon wasn't that close. And you're displaying the exact failure that I mentioned: You don't seem to realize just how quickly the moon moves. If the moon were doing this, if it truly were tidal stresses, then it should have happened either this weekend or two weekends prior when the mechanism for causing such an event was at its strongest.

By your logic, we should consider the gun because it was in the room despite it being disassembled and with no ammunition.
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Daphydd
Lets play some music
07:47 PM on 03/15/2011
Thanks for this reality check. I've read many posts on this site suggesting that the moon is somehow causing or triggering earthquakes. This has been suggested many times over the years, often by unqualified people making earthquake predictions. If there was a causative effect, scientists would be very interested in it.