Wrap up, get out of the city – see the rare beauty of the northern lights across Britain tonight
Compare the bucket lists of your friends and the chances are that seeing the northern lights will be on many of them. So the news that, instead of trekking northwards to Norway or Iceland, you can just step out of your back door to see them sounds like a dream come true. In the past couple of nights many people in the UK have done just that, and in some cases as far south as the home counties.
But is it as easy as that, and what are the chances of seeing something tonight?
Although the northern lights, or aurora borealis as they are technically known, originate in solar activity, they have occasionally been seen beyond the polar regions for thousands of years. Even the Ancient Greeks and Romans knew of them from appearances over their native lands.
Every so often, the sun emits strong streams of particles that subsequently interact with our upper atmosphere and cause the thin gases to glow, in much the same way that gas in a neon sign glows with a characteristic colour. Earth’s magnetic field directs the particles towards the night side of the polar regions, which is why they are much more commonly seen in the Arctic and Antarctic.
Solar activity waxes and wanes over a period of about 11 years. We are now coming out of a period of what’s called solar minimum, where sunspots are often absent, but solar activity is now on the increase.. When the sun is more active, it is more likely to erupt these streams of particles, and they tend to give stronger displays.
Right now there’s one moderately large sunspot on the sun, but what has given rise to the current spurt in the northern lights is an event called a coronal mass ejection (CME). These can occur any time, but this is a CME that is sufficiently strong as to give an auroral display visible from England and farther south, which is rare.
Sky-watchers, in particular, remember the dates of the big events. On 14 March 1989, I could see streamers of the aurora over my house in Middlesex, despite moonlight, and on 8 November 1991, another goodie. And the best was 6 April 2000, when I saw the classic view of curtains of the lights shimmering through my car window as I travelled along the M40 past High Wycombe to get a better view from the country. Since then, I haven’t seen anything particularly spectacular, and the current activity is actually not overly unusual. But what’s changed is the ability to alert people through social media and online, and the press interest. These days, the TV weather forecast will often tell you to get out there, but back in 2000 that didn’t happen.
So, should you put on your coat and set up your deckchair tonight, what might you see? There are no guarantees, and the activity can come and go within a matter of minutes. Clear skies are required, obviously, but also you need to know what you are looking at.
Don’t expect to see anything like the photos and videos with dancing red and green streamers. Sadly, most of the displays you see on TV are speeded up for the sake of effect, and cameras are much more sensitive to the colour than our eyes. I have to give this warning even when I do northern lights trips to the Arctic aboard cruises. Only the very brightest displays are strong enough to show colour to the eye, and most appear as grey. So taking a photo really helps to confirm what you’re seeing. Usually the structures of the aurora move quite slowly, but I’ve witnessed some very rapid displays, including one that appeared like a whirlpool above my head.
If you want to get a picture, most modern cameras, including phone cameras, will automatically adjust to take night shots, so be prepared to keep the camera still for a longer exposure time. Green is the most common colour for the aurora, but when there is a strong display the higher and more rarefied oxygen molecules can glow red. A display near the horizon as seen from more southerly counties could well be only the red part, whereas those farther north will see the same glow higher in the sky, with green at the bottom and red at the top.
Improve your chances of seeing something by getting away from city lights and finding a place with a low northerly horizon. Keep an eye ona tracking site for hourly updates, but don’t wait until they show strong activity, as by then it may be too late. Displays don’t always occur due north, but that’s the most common direction. And above all, wrap up well!
Robin Scagell FRAS is vice-president of the Society for Popular Astronomy and is an astronomy cruise lecturer