Blog Roll

Earthquakes, tsunamis and supermoons! Oh, my!

Are we all doomed?!

Dubbed the “March supermoon” it’s going to be one big old full moon tonight.  It’ll actually be the largest we’ve seen for the last eighteen years and some crazy things are being said about its affects with one geologist, Jim Berkland, even warning California is at imminent risk of a huge earthquake because of it.  Given the recent quakes in New Zealand and Japan – both of which apparently occurred in so-called lunar-risk windows – I thought this worthy of further investigation.  What is this supermoon all about, what’s true and what’s false about how it could affect us?

Full moons are associated with all sorts of insane ideas, from lycanthropy (werewolves) to increased birth rates, casino payout rates and kidnappings.  And of course insanity itself: the word lunatic derives from the Latin luna, meaning moon.  However, numerous studies have been conducted and have failed to find anything of interest correlating lunar cycles with human behaviour.  The moon is known to trigger behaviour in many forms of plant and animal life from turtle eggs hatching to coral spawning; its gravity distorts the sea that wraps our planet causing the tides; and many evolutionary biologists believe that without the stabilising effect of the moon on Earth’s rotation, life here may not have evolved at all.

Earthquakes

The idea that the moon might trigger earthquakes is scientifically credible, if not proven.  The same forces that raise the tides in the oceans also pull on the Earth’s crust.  Yet why would a full moon mean an increase in earthquake risk? That’s just reflected sunlight isn’t it? Well, it’s all about position.

The full moon and the supermoon are separate events to do with different lunar cycles.  The full moon cycle (the synodic month) happens every 29.5 days but the moon orbits the earth every 27.3 days (the sidereal month).  This is because the earth is also orbiting around the sun.  The moon appears full when it is the opposite side of the Earth compared to the Sun, so that the sun’s light is reflected back towards us, rather than the moon shadowing the sun from us and appearing dark.  That’s the full moon.

These orbits are not perfect circles but ellipses (ovals), so the moon also moves closer and farther away from the earth during this cycle. At its closest point every 27.3 days (the lunar perigee), its gravitational pull is strongest and tides are therefore higher.  However, the orbits also wobble in much the same way that a spinning top wobbles.  The moon’s orbit wobbles every 18.6 years.  At its peak the moon reaches its closest physical position to the Earth – and that peak occurs today.  That’s the supermoon.

The moon is not alone in exerting tidal forces on Earth however, the sun also does, which is why we experience seasonal variations like the spring tides.  It’s March, so the Sun’s tidal influence is now reaching a peak, the 18.6 year cycle is peaking (the supermoon) and it’s also a full moon, so the moon and sun are on opposite sides of the earth, causing even larger tidal forces.  That is why Jim Berkland thinks the risk is higher than usual.  His logic is sound.

Is the observed correlation between the moon’s position in its 18.6-year cycle (or any other lunar phase) and earthquake activity just a coincidence though? Do the data support the hypothesis?

“There’s no evidence to support that,” said John Bellini, a geophysicist with the survey’s National Earthquake Information Center in Golden, Colorado. “There were some studies in the past that tried to link lunar effects to seismicity and there was nothing found.”

Berkland is not just factoring in lunar cycles though.  Berkland also uses strange animal data in his predictions, such as spikes in reported missing pets and unexplained fish kills, which some feel makes him seem even more on the kooky side – however his arguments again follow a logic.  Many animals use the earth’s magnetic field to navigate, but high tectonic plate stresses leading up to an earthquake can produce enormous piezoelectric activity that can distort the local magnetic field leading to aberrant animal behaviours and fish kills.

Berkland is convinced that the data are all pointing to a high-risk scenario for California.  He’s a maverick for sure, but he’s also a scientist. He’s not out to scare people, and he’s not saying there will be a quake, just that the risk factors appear to be higher.  Don’t be scared, be prepared, is his motto.

The jury is certainly still out on this one, but one thing scientists do agree is that California is 99.9% likely to experience a massive earthquake in the next 30 years.  Whether it happens in the next few weeks during Berkland’s risk window remains to be seen.

Moon illusion

On a less depressing note, the moon will appear very large tonight, possibly even frighteningly so.  Rest assured though that although it is technically closer than usual, it’s still 356,577 kilometers away.  Most of its apparent size is down to a well-known illusion, known as the moon illusion.  When the moon is lower in the sky, it appears larger to us because of the way our brains interpret size using visual and positional clues.

Professor Akiyoshi Kitaoka, who kindly permitted me to use some of his stunning illusions for my article on perception versus reality, has a nice demonstration of the moon illusion on his site.

Simulating runaway nuclear reaction… with mousetraps and golf balls

In an inspired bit of physics teaching, physicists at St. Mary’s University in Halifax, Canada have produced a video that simulates the runaway nuclear reaction using a set-up of mousetraps and plastic golf balls, . Each plastic golf ball represents a neutron, and the loaded mousetraps are unsplit uranium nuclei, or nuclear fuel. When a golf ball is dropped onto the arrangement, it sets the process in action by tripping a single mousetrap. The reaction proceeds until its mousetrap “fuel” is spent and the action fizzles out.

Given the terrible events happening in Japan right now, if you’ve ever wonder how nuclear reactions work, this is an excellent metaphor for uranium fission - and why it’s so hard to control…

Full details here.

My thoughts go out to all our Japanese friends during this terrible time.

Gruff 

Jehovah’s Witnesses deliver hypocritical religious propaganda…

…without a trace of a irony.

A charming mother-and-daughter pair of cult members knocked on my door this morning. I said I was atheist and the mother looked delighted and said she had something especially for me, asking if I thought ‘atheism was on the march?’ I brightly replied that it certainly was which seemed to make her very nervous suddenly.  I took the two leaflets she gave me, figuring they’d make fun reading.  I wasn’t disappointed.  It’s pages and pages of low IQ drivel, poorly researched, twisted-viewpoint propaganda.  And it’s wonderfully and hilariously hypocritical.  Poor things. I regretted not invited them in for a cuppa to see if could talk some sense into them.

Read this first paragraph (remember they actually came to my door to deliver this!)

Skepticism

I found this extremely well-written explanation of what Skepticism is, and what it is not.

It covers Burden of Proof, and some common misconceptions about Skepticism, that it is for example, a belief system (it is not, it’s a methodology).

Highly recommended reading.

I’ve switched to Tumblr…

It’s really rather lovely, and so is the import-from-blogger tool written by the very clever Jonathan Tran (thanks for your help importing my blog!).

This means nothing to you… (aaah Vienna), but for me it means a lovelier blog experience.  And no-one likes a hard blog, do they?