Wednesday, November 14, 2012

Doomsday Scenarios: Prophesy vs Science

You no doubt have heard of various 2012 "end of the world" doomsday scenarios that have been depicted in Hollywood films, on TV, in tabloid news magazines, and of course, online. These are all baseless and without any scientific merit. Since there are several “End of the World” claims circulating online, let's take a look at the top four scenarios.

Asteroid Impact
This is a common disaster scenario seen in many films and there are claims that an asteroid impact will strike the Earth in December 2012 and will cause mass extinction. This is completely false. Now, the Earth has been hit by asteroids before, and in fact, we believe a large impact is responsible for eliminating the dinosaurs millions of years ago. So this may happen in the future again, and from the geological record it seems as if every few hundred thousand years asteroids more than a kilometer across have impacted and caused global disasters. So it is important to survey the sky and to see if we can find such Earth-bound impactors well before they reach us! Indeed such work is the primary reason why this Dec 2012 impact hoax is not credible! Large asteroid surveys by NASA, for example, have not found any large asteroid/comet that is on a collision course with Earth in the foreseeable future. We face much greater threats in our daily lives from auto accidents, disease and other natural disasters than the threat from an asteroid impact.

Mayan Calendar
A popular end-of-the world claim is this notion that the Mayans predicted the world would end on December 21, 2012 since their calendar ends on that day. This too is nonsense. The basis for this claim comes from the fact that the Mayan "long count" calendar completes a cycle on December 20, 2012. Hence, this must necessarily imply that the world ceases to exist on December 21, right? I like to point out to people who ask me about this claim, the modern calendar ends on December 31 every year, yet every year, January 1 still always follows! Like modern day people, Mayans would likely celebrate the end of one cycle and prepare for the start of a new one. Just because their calendar ends, it does not mean they are predicting the End of the World!

Solar Storms
Another fanciful way some have envisioned the apocalypse to arrive is via a massive solar flare or solar “storm.” And like other astronomical end-of-the-world scenarios, there is a kernel of truth to this story, but little else to support the claim. Our Sun is the reason why we have life on our planet. It provides us with the necessary warmth and light for life to flourish on our planet. Now, our Sun does indeed go through a solar activity cycle in which the number of sunspots peak and then decrease with time. It turns out that massive solar flares are correlated with the increase in sunspots and can produce large quantities of charged particles (i.e., electrons, protons) directed toward Earth. Fortunately, our planet produces a magnetic field that protects us from these energetic, charged particles. It deflects these charged particles to the polar regions of our planet where we observe their interaction with the Earth's atmosphere as beautiful auroral displays that sometimes can reach as far south as Virginia during an intense storm!
Some solar physicists have suggested that this current solar cycle may be more energetic than the last, and we are indeed on our way to another solar maximum during 2012. This is the kernel of truth referred to in most doomsday claims. The problem with this doomsday scenario is that even a massive solar storm would have little impact to life on the surface of the planet. Unprotected astronauts and satellites would be impacted by large solar storms though. Science Operations Teams of the Chandra X-ray Observatory (Chandra, like the Hubble Space Telescope, is a NASA “Great Observatory”) at the Harvard-Smithsonian Center for Astrophysics,had to suspend science observations when a large solar storm erupted because of the potential damage to their detectors. Similarly, on March 13, 1989, a large solar storm did cause six million people in the province of Quebec to go without power when the solar storm caused a surge in current. Therefore, if a large solar storm was aimed directly at us, it could cause secondary problems like blackouts, damage to satellites and to unprotected astronauts, but it would not destroy the Earth! Because of the concern to satellite damage and the possibility of blackouts, several NASA missions like the Advanced Composition Explorer (ACE), the Solar and Heliospheric Observatory (SOHO) and the Solar TErrestrial RElations Observatory (STEREO) monitor solar "weather" and can provide us with up to an hour notice on the approach of a large solar storm. Now, five billion years in the future, when the Sun runs out of nuclear fuel and swells into a red giant, that will indeed be a bad time for life on Earth! But we have a long time to pass before we worry about that problem!

Changing Magnetic Fields
Another popular doomsday scenario suggests that on December 21, 2012, the core of our planet will re-orient in such a way that it will cause a change in our protective magnetic field. Such nonsense was the theme behind the popular Hollywood blockbuster called The Core (2003), which starred Hillary Swank and Aaron Eckhart. The generalized scenario suggests that not only will we see the rapid reduction in magnetic field strength, but we'll see the magnetic poles rapidly reverse polarity (i.e, the north magnetic pole will be located over the South Pole and vice versa). The consequence to us on the surface of the planet, according to this nonsense, is that we'll be exposed to large amounts of radiation from the Sun (see above!) and from "cosmic rays" that come from interstellar space! Some end-of-the-world claims even further predict that because of this change in the Earth's magnetic field, communication and military satellites will drop from orbit; and that without GPS, airliners will fall out of the sky! The kernel of scientific truth in this doomsday scenario is that the Earth's magnetic field is changing! Scientists with the Geological Society of Canada head to the Canadian arctic every few years to monitor the location of the north magnetic pole. Currently, it is located in northern Canada about 600 km from Resolute Bay (population 300). Since 1831, we've been monitoring its changing location. During this time period, the location of the North Pole has been shifting north as fast as 60 kilometers per year. Scientists have been monitoring the location of the South Pole for the last 100 years and it has been moving toward Australia at the rate of 10-15 kilometers per year. And, apparently, the strength of the global magnetic field has weakened 10 percent since the 19th century. But is the Earth's magnetic field collapsing? NO! In fact, as incredible as these changes sound, this is mild compared to what Earth's magnetic field has done in the past. For instance, the magnetic poles completely flip! We know this because geologists have found evidence for these reversals in the magnetism of ancient rocks. But these flips are unpredictable! The last one was 780,000 years ago. Will there be another one? We don't know. As for the 10 percent decline, the magnetic field strength is constantly changing. The latest supercomputer model of the Earth's interior, where the magnetic field comes from, suggests that the magnetic field increases and decreases, poles drift, and sometimes they flip altogether. These reversals take a few thousand years to complete and is therefore not "instantaneous." Moreover, during this time, the magnetic field does not disappear, it simply becomes incredibly complicated and it still protects us from solar storms and radiation from space. This geomagnetic reversal is not connected to the Sun's solar cycle and does not occur with any kind of "clockwork regularity." We are not "due" a magnetic flip as we cannot predict when the next one is going to occur! So there is absolutely no scientific evidence to suggest that this is going to happen in December 2012!

I could go on and on as there is just so much 2012 end-of-the-world nonsense. All of it is without any scientific evidence whatsoever; it is all bunk and scare-mongering! Our Earth has been here for 4.5 billion years and will continue to be here until our Sun reaches the end of its hydrogen fuel supply in the core in another 4.5 billion years. If you are truly worried about the Earth’s fate come this December, let me encourage you to donate your unneeded financial resources to the upkeep of this blog as you won’t need it in 2013!

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