The end of the world. Really?

I suppose there are some people in the world with access to the internet or mass media who haven't heard the stories about how the world is possibly going to end on December 21, 2012. The usual reason for picking this date is that a calendar made by the Mayans several centuries ago only runs until this date.

Predictions of the end of the world are not new, and there have been thousands of them over the centuries, and they fall roughly into two classes: religious prophecy and weirdness, with the latter including psychics, UFO believers and the truly insane.

Predictions of the end of the world based on religion seems almost exclusively confined to Christianity and it is easy to ridicule people from the past who knew less that we knew now, but I found a few real scientists who devoted at least some of their time to trying to calculate the end of time.

John Napier and Jakob Bernoulli predicted the world would end in the late 17th/early 18th centuries – Napier predicted 1688 or 1700, while Bernoulli predicted a comet would wipe out the Earth in 1719. Isaac Newton made the safe prediction of 2000.

Another I put in the scientist category is Bishop James Ussher, often ridiculed for his estimate of 4004BC for the creation, but he based this on matching Bible stories with independent folk histories and produced the best estimate from the available data.

When Charles Darwin walked past the end of my street in the Blue Mountains on January 17, 1836, and looked out over the Jamison Valley, he assumed that he was looking at a drained seabed. He did not know that the Earth was old enough to allow the "tiny rill of water" to carve out the valley, and it wasn't until about a century later that the discovery of radiation and plate tectonics could explain both the age of the Earth and how the sedimentary rock he stood on managed to get almost a kilometre above sea level. Science is always a work in progress, and it is not fair to judge people harshly for doing the best with what they had at the time.

The outright crazy predictions are the most fun, although they raise a serious question about science education that I will revisit later. Nostradamus is there, of course, predicting July 1999. Sheldan Nidle had 16 million spaceships coming in 1996, and Nancy Lieder had the twelfth planet, Nibiru, crashing into Earth in 2003 (both dates since revised to December 21, 2012). Ronald Reagan's psychic adviser Jeane Dixon predicted February 4, 1962, later updated to "2020-2037". Assorted people worried about the Large Hadron Collider in 2010 and Comet Elenin in 2011, with the Earth being sucked into a black hole or shattered into a million pieces.

Dangerous predictions

As much as we may laugh at these bizarre end-of-the-world predictions, it's sobering to remember that some have ended in tragedy.

Charles Manson convinced his followers to murder strangers because the end was coming, and Jim Jones predicted the end in 1967. Fortunately nobody took any notice of him then, unlike 11 years later when he was able to convince people to kill their children and then themselves.

This brings me to the danger of failed prophecies. Believers have been known to sell their houses and property, leave their jobs and families and harm themselves and others. I've mentioned Charles Manson, but in Uganda in 2000 almost 800 people died because the world hadn't ended, we remember Marshall Applewhite and Heaven's Gate in 1997 when a group of intelligent young people killed themselves, the Aum Shinriko cult released sarin gas into the Tokyo subway in 1995 to hasten the end of the world.

There is also the danger of wasted time and resources needed to assure people that the next prediction is unlikely or even impossible. NASA have been receiving a large number of enquiries from fearful people, many of them young enough to not have experienced some of the past scare campaigns. They have had to waste time that would have been better spent exploring the cosmos to produce websites explaining why things just aren't going to happen.

Five reasons the world won't end

Here are the five most common disaster predictions:

• The planet Nibiru, larger than the Earth, will crash into the Earth – if something that big was nearby at least some of the thousands of astronomers in the world would have detected it by now, and even if it were invisible the perturbations it would have caused in planetary orbits would have been noticed.
• The Earth's rotation will change, either stopping completely, reversing spin or changing its axis of spin – all I really have to say here is "inertia". It isn't going to happen.
• All the planets will be in a straight line and the resulting gravity will cause devastating tides – even if the planets did line up, which they are not going to do, their gravitational effect on tides would be almost immeasurable when compared to the effect of the Sun and Moon.
• The Earth's magnetic field will reverse, with the poles swapping position – this happens on average every 400,000 years and we are overdue at about 700,000 years since the last time, but even if it happened (and it takes a long time, so it would have been noticed by now) it wouldn't have much effect except on compasses and pigeons.
• Time will just stop when the Mayan calendar runs out of days – the Mayan calendar was cyclic, just as ours is, and this is just as likely as there being no January 1, 2013, because the calendar on my office wall only goes to December 31, 2012. This is probably the silliest fear of all.

I mentioned science education before, and that is what really concerns me about the fears of December 21.

Knowledge of basic science, the stuff I was taught in primary school and the first years of high school, is enough to know that these predictions are not just unlikely, but actually impossible. No huge planet can wander through the solar system unnoticed. A spinning body with the mass of the Earth can not suddenly change its axis of rotation or direction of spin. Major shifts in the magnetic field of the Earth can't happen suddenly.

It's all very well to laugh at these silly predictions, but the laughing should stop when you realise that the fact that some people aren't laughing is a sign that they are lacking a basic education in how to tell fantasy and fiction from fact. And there be dragons in that unknown land.

This article was published on the ABC Science web site on December 12, 2012

This was based on a talk I gave to Canberra Skeptics on December 8, 2012