This coming Tuesday marks the 150th anniversary of a unique astronomical event that has repercussions even today. On the morning of September 1st, 1859, Astronomer Richard Carrington found his routine of carefully drawing and recording the transit times of sunspot groups disrupted by an odd phenomenon emerging on the face of the Sun. The day dawned unusually sunny over his private observatory in Redhill, England, and 33 year old Carrington had taken to his usual daily task of sketching sunspot groups projected onto a screen in a darkened room. The scope used was a 2-meter long brass refractor, (scopes were often measured by focal length instead of aperture in those days) and it yielded an 11-inch diameter projected image of the Sun. the Sun itself had been extremely active most of the year, and there was plenty to draw. Carrington was not, however, ready for what appeared on the disk of the Sun at about 11:18 AM local: two kidney shaped beads of light appeared to stab upwards from an enormous sunspot group. This group was active, and as the chronometer ticked away the time in the background, Carrington realized he was witness to a rare event; what we now know as a white-light solar flare. He rushed back into the house to nab a witness, but as they returned not more than sixty seconds later, the flare was largely gone. After a span of five minutes, the flare had covered an estimated 35,000 miles over the face of the Sun and had faded entirely. Carrington had managed to do a hurried sketch and ran the numbers in his head; the material in the flare had to be moving at an astonishing 420,000 miles an hour!
But Carrington wasn’t the only one to lay witness to this event; a truly global show was to come at sundown. Over the night of September 1st and into the early morning of the 2nd, the populated latitudes of North America and Europe were treated to an auroral display of northern lights, the likes of which have been seldom seen before or since. In fact, displays of northern lights stretched down as far as Puerto Rico and the Canary Islands, latitudes that scarcely see Aurora Borealis! In this age of cell phones and instantaneous communications, its hard to imagine the fear and wonder this must have evoked. In Arctic latitudes, aurora are common enough for folks to be familiar with them; these northern lights, however, were occurring over places and people who had largely never heard of, let alone seen such things! The natural presumption of many was that a fire lurked just beyond the horizon; perhaps only the great Leonid meteor storm of 1833 provoked more fear and wonderment.
The geomagnetic effects of the storm were felt by the new instruments of the time. Down the road from Carrington’s’ humble observatory, the magnetometer at the stately Kew Observatory in London operated by Balfort Stewart was recording inflections that were off of the charts as well. Other anecdotal tales of the “Great Super Flare of 1959” include telegraph operators getting shocked by their equipment, sometimes even after the battery was disconnected! Imagine your cell phone operating, even after you’d pulled the battery out…spooky! (Now that’s some current!) One telegraph office was even known to have caught fire as a result of the current induced by the storm.
But beyond the pretty light show and a few amusing foot notes, the Carrington Super flare told us something fundamental about the nature of our solar environment and our place in it. A flare such as the one that Carrington witnessed was of the rarest X-Class variety, releasing up to a billion megatons of energy from deep in the photosphere. Most of the time, these eruptions simply pass the Earth, such as the October 28, 2003 Halloween X-11 flare, and are thankfully not aimed directly at us. The Corneal Mass Ejection (CME) of 1859 smacked the magnetosphere of the Earth head on, sending a cascade of high energy particles and depressing the auroral oval over the southern and northern poles. This event also underscored the effects that the solar environment can have on terrestrial affairs, and Carrington was the first to deduce the Sun-Earth electromagnetism connection. In Carrington’s time, the eleven year sunspot cycle was already well understood; Carrington laid ground work for further understanding the dynamics of solar rotation and what became known as Sporer’s Law, or the fact that sunspots develop high in the solar latitudes at the beginning of a solar cycle, and then progress downward towards the solar equator at the end. Each 11 year solar cycle sees a reversal in sunspot polarity, and the solar cycle still bears his name. For example, we are now in the sputtering beginnings of Carrington Solar Cycle #24.
So what does these have to do with us? In Carrington’s time, the pinnacle of technology was the telegraph… maybe, if your ‘burgh was cutting edge, the town post office might have one. But other than the fact that the aurora may have caused your roosters to crow at 2 AM, life was pretty much unaffected for your average Joe. This wouldn’t be true today. We rely on technology much more intimately than most of us realize; and I’m not just talking about your dashboard GPS going on the fritz or your Blue-ray becoming possessed. Emergency, military, and commerce now all rely on a variety of electronica. A truly large CME like Carrington’s has never happened since the advent of the radio or telephone. The impact could dwarf hurricanes Andrew or Katrina, and everyone knows how well we were prepared for those fiascoes! In 1989, a solar storm plunged Quebec into darkness. In 1972, Apollo 16 & 17 astronauts narrowly missed being fried by a similar event. As we venture further out into space, understanding and protecting ourselves from these space-weather events will be tantamount. A recent study by NASA of the impact of a large CME on the eastern seaboard of the US is sobering; not only would a modern day super flare effect primary systems such as satellites and cell phone communications, but it would have lasting secondary effects, such as frying hard drives (!) and causing toilets to malfunction!
Its hard to believe that our currently quiet sun could have such a vicious streak. Perhaps we’re just being lulled by its current mediocrity. Looking out at other stars, we see flares of an intensity that would make life as we know it impossible. One thing is certain, the Carrington super-flare of 1859 was not a singular event. The only true question as we remember and mark this fascinating event in astronomical history is; when will the Sun once again reach out and touch us?
(Editor’s note, watch this space for a review this coming month of The Sun Kings: The Unexpected Tragedy of Richard Carrington and the Tale of How Modern Astronomy Began as we continue the saga!)