Is the Sun about to rise from the west?
Is the Earth going to plunge into darkness for three full days later this month?
These are the questions I have been asked about rumours that have been spreading like wildfire on social networks for the past several weeks. What is the story?
The first story goes like this: Nasa has “announced” that the Earth’s magnetic field will soon flip, so north will become south and east will become west; hence, the sun will be rising from the west! People then quickly recall that the sun rising from the west is one of the great signs of the Apocalypse, the Day of Judgement. And so needless to say, this “news” found great interest among the public and spread faster than a typical rumour.
The second story goes like this: Nasa (this label gives credence to any “info”) has “announced” that the sun has been so active lately that a special alignment with Earth on December 21 will produce the biggest blackout in the history of human civilisation, as charged particles from solar eruptions will disrupt power lines on Earth and satellites in orbit. (You may recall that, two years ago, December 21 was the special date of another Apocalypse, the one “predicted” by the Mayan calendar.)
Of course, there is no truth to either one of these scenarios, but it is instructive to review the real scientific information upon which these stories were constructed.
In case of the first one, I must explain that Earth’s magnetic field flips every half million years, on an average. That is due to irregularities and turbulences in the electric currents inside Earth. And indeed, we have geological and fossil records showing the planet’s magnetic field in different directions at various geological epochs. Such a reversal has occurred hundreds, perhaps thousands of times in our planet’s geological history (of 4.5 billion years). The last time this occurred was 786,000 years ago. Now, geologists had recently been noticing a weakening of the Earth’s magnetic field and since a reversal was overdue, they forecast one sometime in the next 1,000 or perhaps 10,000 years.
Things took a sharp turn last June, however, when new measurements from European Space Agency satellites were presented at a scientific conference in Denmark, showing that the weakening of the magnetic field had accelerated: It is presently decreasing at a rate of 5 per cent per decade instead of per century, as had previously been determined. Thus, a reversal could occur in the next 100 years instead of thousands of years.
The media then reported that “the Earth’s magnetic field may flip during our lifetime”, and someone (incorrectly) inferred that ... the sun may soon rise from the west! I must stress, however, that researchers are not even claiming that the magnetic field will soon flip, only that it may. Indeed, geological records show that sometimes the field weakens, but does not flip. And when it does, the reversal usually takes about a century to complete!
But what if it does? Doesn’t the magnetic field protect us from harmful solar particles?
A reversal does not necessarily mean that the magnetic field totally vanishes while flipping over. The field becomes chaotic, with multiple poles appearing over the planet. Moreover, palaeontological record does not show any past extinctions corresponding to magnetic reversal times. So while we may expect some sensitive animals to be affected by a weak magnetic field (many birds will lose their “internal compass” ability) and some humans may be more sensitive than others to magnetic variations, no large-scale disasters will likely occur.
But going back to the original story, if and when the Earth’s magnetic field does flip, would the Sun then be rising from the west?
That would only be true if one defines east and west using magnetic directions. For astronomers and almost everyone else, directions are set by the locations of stars and constellations around us. And since the rotation of the Earth will not change in any such reversal, the Sun will still arise from the geographic — though not the magnetic — east!
Indeed, we must remember that the Sun’s rising and setting is only an apparent effect that is due to Earth’s rotation around itself. Hence, if and when the Earth’s magnetic field does reverse its poles, Earth’s rotation will not be affected and Sun will still rise and set in the same way as ever.
On the second story, scientists have known for centuries that the Sun goes through an 11-year cycle of magnetic activity, thus producing flares and eruptions in quasi-periodic manner. And the past two years have corresponded to a high period of solar activity. But nothing special will occur on December 21. In fact, the Sun’s activity is now decreasing. No particular bursts of charged particles can be expected and thus no special power blackouts or satellite disruptions.
Science literacy has become more and more important these days, as information spreads more quickly than ever. If the public is not equipped with the basic information that allows it to filter correct information from wild rumours, much time, effort, and energy will be wasted in correcting such stories. Moreover, panics may occur among the public (as we may recall from the ‘2012’ Mayan “apocalypse” craze) and people may resort to irrational solutions (e.g. buy special “products”) that will help them deal with the situation, at least psychologically.
More than ever, scientists, educators and media communicators have an important role to play in making science and the world understandable and enjoyable, not fearful, for the general public.
Nidhal Guessoum is a professor of physics and astronomy at the American University of Sharjah. You can follow him on Twitter at: www.twitter.com/@NidhalGuessoum.