Unusual streak of light over Canadian sky excites netizens and stargazers 

Imagine this, it’s just before Christmas and you have travelled all the way to Norway and one fine night, while stargazing, you witness one of the most beautiful celestial phenomena. It’s an unusual streak of colourful lights spread across the night sky. At first you are mesmerised but then you literally thank your stars for placing you at the right place at the right time. After all, you just experienced the Northern Lights!  

Well, something similar yet different happened in southern Canada a few days back. An unexpected line of light was observed by people, something that is said to have been triggered by a solar storm, that had hit the Earth recently. Guess what? Contrary to popular belief, it wasn’t really the northern lights, rather something called STEVE phenomenon. Interestingly, this chance occurrence has resonated well with both netizens and amateur stargazers. Here’s everything that you need to know about it. 

What exactly happened in Southern Canada? 
As revealed by astronomy author and photographer Alan Dye on Twitter recently, the northern lights (Kp5 aurora) lasted for a few hours and then subsided. However, right after they faded away, another rare streak of greenish and purplish light was seen across the night sky near southern Alberta, that lasted for more than 40 minutes past midnight. This is what is known as the STEVE phenomenon.  

STEVE phenomenon: A bird’s eye view 
First things first. What’s the Northern Lights or the aurora? Simply put, aurora is an atmospheric phenomenon created by charged solar particles that strike the upper atmosphere, forming coloured lights in the sky. Aurora is usually named ‘borealis’ or ‘australis’ depending on whether it is in the Northern or Southern Hemisphere respectively. As you can guess, aurora borealis is popularly called the Northern Lights, while its southern counterpart is called the Southern Lights. Now, let’s come to STEVE phenomenon. 

As it turns out, STEVE phenomenon is an aurora-like light that is solely found in southern Canada, as it falls in the right geomagnetic latitude or the sub-auroral zone. In fact, guess what, STEVE was discovered in the same region, back in 2016 by a team of Canadian scientists. While much of STEVE still remains unknown, what’s know is that it expands to Strong Thermal Emission Velocity Enhancement and is caused by 25 kilometres wide ribbon of hot plasma. Scientists also believe that it is not a normal aurora. In fact, some even don’t consider it to be an aurora at all. However, one thing is for sure, the spectacular show of lights helps in the better understanding of the complex space environment, allowing astronomers predict and mitigate its consequences on communication signals on Earth.  

Now, let’s come to its major differences with the aurora. Firstly, this atmospheric optical phenomenon turns up as glowing purplish ribbons of light with green spikes coming off obliquely parallel to each other, unlike aurora that’s more widespread, usually yellowish or reddish in colour. However, the most significant distinction is the fact that it appears in a lower latitude and moves east to west, unlike aurora borealis that is consistent with higher latitude, more specifically near the Arctic Circle and moves south to north. Interestingly, STEVE usually follows aurora and not the other way around.