Aurora Australis: The Southern Lights

Few sights in the natural world can compare with the dancing, shimmering, pulsating glow of the auroras, and enjoying it is definitely a possibility for travelers to the bottom of the world.

On the whole, it’s probably safe to say that the aurora borealis—the Northern Lights—are the most familiar of the two “brands” of auroras experienced on Earth. The auroras of the Antarctic and elsewhere in the Southern Hemisphere, the aurora australis or Southern Lights, are less widely known. That’s not because they’re any less spectacular, not by a long shot. (Some contend they’re more spectacular, in fact.)

The main reason the Southern Lights are somewhat lower-profile is simply because there’s a lot more landmass up in the Northern Hemisphere than in the Southern Hemisphere, and the primary aurora zone in the North is much more populated. Many countries and cities in the higher latitudes of the Northern Hemisphere market themselves as aurora-viewing destinations, and indeed Northern Lights tourism is quite the big deal. Seeing those gorgeous and phantasmal pillars in the sky is, after all, on the bucket list of many people, willing to make the effort to travel to places such as Scandinavia, Iceland, Canada, and Alaska for a shot at it.

The primary territory of the aurora australis, by contrast, is mainly the farflung pelagic wilderness of the Southern Ocean and—yes—the great White Continent itself, the most remote land on Earth.

In this article, we’ll flesh out the basic science behind the Northern and Southern Lights and detail how to potentially spot the latter on a once-in-a-lifetime Antarctic journey.

Understanding Auroras, the Northern & Southern Lights

Auroras arise (to mesmerizing effect) on account of the interaction between the solar wind and Earth’s magnetic field, or magnetosphere. The Australian Antarctic Division does a bang-up job explaining and illustrating this interaction—highly recommended—but we’ll summarize it here.

The solar wind describes the high-speed output of charged particles—electrons and protons—from the Sun: the other, smaller component of our star’s mass loss besides that life-sustaining release of solar energy.

While there’s also a stream of solar wind issuing from the Sun, the magnitude varies on an 11-year cycle. More significant emissions occur with significant solar storms generated by phenomena such as solar flares and coronal mass ejections. Auroras are benign—and beautiful—repercussions of such storms, which, on the other side of the spectrum, can wreak havoc with radio communications, electrical transmissions, and other technology.

The Solar Wind’s Effects on Earth

Earth’s magnetosphere helps buffer the planet from harmful solar radiation. The solar wind streams around the planet; much of it is deflected away, but some of its charged particles sweep along the looped lines of Earth’s magnetic field, which converge at the two poles.

Some of those particles breach the magnetosphere and become trapped within it, sweeping at great speed along the magnetic-field lines and colliding with atmospheric gases, namely oxygen and nitrogen. They excite these gases—that is, they transfer energy to them. And one way the oxygen and nitrogen deal with that excess energy is by releasing it in the form of photons: light.

Oxygen at higher altitudes tends to release red light, while at lower altitudes it emits green light. Nitrogen produces red and violet light. It’s these colors that are the predominant hues of the Northern and Southern Lights, although our naked eye often perceives some or all of the auroral pillars and curtains as whitish. Cameras often better capture the full colorful brilliance of auroras.

Because of the convergence of Earth’s magnetic field at the North and South poles, it’s those extreme points—and specifically the magnetic poles, as opposed to the nearby but not identical geographic poles—and their surrounding auroral oval where the auroras are most commonly observed. The Northern and Southern Lights often coincide, given strong solar-wind emissions send charged particles sweeping toward both poles.

Under the right conditions, including following high-magnitude solar storms, the auroral oval may enlarge to encompass much broader areas, offering rare opportunities to enjoy the Northern or Southern Lights at lower latitudes. For example, the Southern Lights are sometimes visible from places such as Tasmania—even the southern tier of the Australian mainland—and New Zealand’s South Island.

The Southern Lights in Antarctica

Antarctica is easily one of the world’s aurora hotspots, but definitely not one of the easiest to appreciate firsthand. While auroras may occur anytime of year, especially near the poles, they are, unsurprisingly, best seen at night. And the most clement time to visit Antarctica is the austral summer, when the Midnight Sun beams away for the better part of 24 hours. Nighttime, if it comes at all (which depends on your location on the White Continent), is a fleeting window during this time of year.

We can envy those hardy researchers and staff who populate Antarctica’s remote research stations over the austral winter, when the roughly around-the-clock Polar Night—and the pristine, unpolluted, frequently cloudless skyscape at the bottom of the world—set the stage for utterly spectacular Southern Lights displays.

Viewing the Aurora Australis (Southern Lights) on an Antarctic Cruise

What are the odds of marveling at the aurora australis on a cruise to Antarctica? Well, there are certainly a few things working against you, not least the aforementioned Midnight Sun. The majority of cruisegoers, furthermore, head for the Antarctic Peninsula—an absolutely gobsmacking place to visit, dishing out some of the most spellbinding scenery and wildlife-viewing on Earth, but not the most propitious corner of the White Continent for spotting auroras. That’s because it’s on the other side of Antarctica from the Magnetic South Pole, which, being a mobile point, currently lies off the East Antarctic coast.

That said, the Peninsula is still, all things considered, a very solid place to attempt to see auroras. And a cruise timed for the “shoulder season” of Antarctic tourism—and particularly the tail-end of the season, in March—gives you longer and darker nights, improving aurora-hunting conditions. The March equinox, marking the halfway point between the austral summer and winter solstices, also often coincides (as does the September equinox, not a feasible time for most tourists to get to Antarctica) with an uptick in auroral activity. The reasons are complicated and also not completely understood, but a leading idea suggests (basically) that around the equinoxes Earth’s magnetic field is most auspiciously aligned with the solar wind and that holes within the field more frequently open up then, allowing more charged particles in.

March, by the way, also happens to offer some of the best whale-watching of the year in Antarctica, and the sea ice is at a minimum, affording maximal access to the White Continent. Indeed, this is a good time of year to venture to more farflung places such as the Ross Sea—which, farther south as it is, gets you deeper into the auroral oval.

It’s also worth pointing out that South Georgia—often combined with cruises to the Antarctic Peninsula—is its own topnotch place to look for the Southern Lights: a nice middle-ground between far enough south, making for decent auroral frequency, and far enough north to enjoy longer summertime nights.