Geomagnetic climax: the Northern Lights tickle the G4 point in France!
Jonquière (Vaucluse), around 11:20 p.m. We can notice the end of the “pan” of the Big Dipper on the left. © Sylvain Gairaud & Brice Haziza
The northern lights of last May have been surpassed. The night of “severe” level magnetic storm was even more spectacular. Spain has even benefited from this enchantment of the sky and space. Amateur observers were surprised to see them from city centers, particularly in Nantes.
To be honest, at the (very) early morning hour when we are writing these lines, after having gone to contemplate and photograph the spectacle in the middle of the night, it continues. The scientific indices are still extremely high, we will come back to this later.
A few photos as a breakfast to illustrate how these northern lights arrived in the sky – or polar lights, it's the same thing, although France has not moved towards the pole…
Show EXIF Slowly, it starts towards the northwest. It’s 10:38 p.m. © Brice Haziza
Show EXIF In 3 minutes, the intensity increases and it is visible to the naked eye (22:41). © Brice Haziza
And then the festival begins:
The Northern Lights therefore arrived from the northwest. © Sylvain Gairaud & Brice Haziza
We can clearly see the green and red colors, as well as the drape of the Earth's magnetic field! © Sylvain Gairaud & Brice Haziza
The central glow to the left of the two prominent trees was bright to the naked eye. The Big Dipper is almost entirely within the field of the aurora borealis. © Sylvain Gairaud & Brice Haziza
And to fully understand what we can distinguish with the naked eye from what a camera in night mode (or “long pause”) manages to image, here is a comparison:
Show EXIF This is what we could see with our own eyes. © Brice Haziza
And practically the same photo of the same sky, at the same moment, with a longer pause and a more efficient camera:
The long pause allows the green color, which is difficult to see with the naked eye, to appear, as well as the drapes of the magnetic field which we could barely guess. © Sylvain Gairaud & Brice Haziza
We recommend following X-Twitter accounts, which monitor and inform the community in real time (NotreEspace, the author of his linesthe excellent Astrostone Or AurorAlpsFor example). You can also watch on SpaceWeather. Exactly, yesterday around 7:30 p.m., all the signs of a fantastic night presented themselves and several accounts raised the alarm:
The KP and G indices are two of the crucial indicators (SpaceWeather.com website). © Brice Haziza on X
The KP index, based on 9, is an index of geomagnetic activity. From a value of 7, auroras can be perceptible, but rather in long pauses on the phone. In May, like last night, the KP index was at 8 at its highest, which is what we need to reach to enter the naked eye visibility threshold, in our opinion.
The G index is that of geomagnetic storms. It starts at 1 for a light geomagnetic storm and was set at 4 last night and last May. G4 is therefore equivalent to a “severe” geomagnetic storm. The map ofauroral oval shows you where the chances of observing the Northern Lights are greatest: the thicker the red, the better!
High KP (8/9) and G4 index = two reasons to look north!
In summary, if Kp = 9 and G = 4 like last night, then you can head towards a clear sky, in clear weather too, and legitimately hope that the earth's magnetic field offers you the wonders of which it is capable.
To be truly rigorous, we must specify that our Earth's magnetic field must be configured in such a way as to allow particles from the ejection of solar matter (known as coronal mass, or CMe) to pass through. This is the Bz index that applies and it must be negative, which of course was the case last night.
The solar and terrestrial magnetic fields must recombine. For this, you need a negative Bz index, so the particles are sucked into the magnetosphere instead of being repelled. © AuroreAlpes (X/Twitter)
But where did this material come from? Areas of our star where the sunspots AR 3848, AR3849 and AR 3850 were located, which we had just photographed with a suitable solar filter (otherwise the telescope would have burned) this Tuesday, the day when the ejections of matter were directed towards the Earth took place:
Show EXIF The sunspot AR 3848 was then perfectly pointed in our direction. It is about 10 times the size of Earth. © Brice Haziza
For 36 hours, let's see what the Sun has expelled and is responsible for our dream night. Note three elements in this incredible suite of photos from the SoHO satellite: the comet Tsuchinshan-Atlas, whose hair shines for several million kilometers in the middle of multiple CMe (solar flares); the burst of solar protons which stains the image with white spots; and Mercury which passes almost anonymously on the left.
A comet, gigantic solar flares and even the planet Mercury (left). © SoHO, gif made on ezgif.com
But will this continue for a long time?
Frankly, as much as we want to be careful and not give false hope: the answer is yes. We are in the middle of the solar maximum – which was theoretically supposed to start in 2025, but is perhaps a little earlier – and the most likely thing is that it will continue for a few months like this. Let's remember that a week ago, the Sun had graced us with the biggest flash of X-rays over the last 15 years!
These cycles last 11 years, but some are stronger than others, and that is clearly the case here. We live in a truly favorable time for astronomical wonder with the Northern Lights, the comet that returns this weekendand space, including the takeoff of the Starship IFT-5 Sunday promises to be unforgettable.
And finally, a photo of what we could see with a little more luck: comet AND northern lights (fingers crossed):
Comet Tsuchichan-Atlas and the Northern Lights! © Riuzhu Chen (X/Txitter)
