Great balls of fire!

A first for me ...

Just a bit of light relief this time …

My colleague Richard Querel shared this great sequence from Lauder taken at about 11:08 pm local time (10:08 UTC) on Friday 31 January 2025.

Pretty impressive! (assuming the movie played OK for you 😊).

It was well after my bedtime but was beautifully captured with an automated multi-camera system for recording sky conditions. This is what the one at Lauder looks like.

It’s part of a world-wide network designed to monitor fireballs. By clicking on that link you can navigate to any network site, including Lauder, to get a real time view of current or past sky conditions, day or night. Nifty …

The sequence of images above is a great example of a fireball that was caused when a meteor from outer space broke up when it entered Earth’s atmosphere and collided at high speed with molecules of air. The average speed of meteors entering Earth’s atmosphere is more than 50 kilometres per second, far exceeding the speed of sound or any man-made projectiles.

The sonic boom - as reported by witnesses nearby - was very noisy too. Due the high altitude of the burn-out (probably around 50 km above us), those sound-effects arrived a couple of minutes later than the light.

It briefly turned night into day and no doubt generated a fair bit of UV radiation as well in that short burst of light.

I wondered whether that UV light striking molecules of oxygen in the atmosphere could have generated a measurable transient increase in ozone. Unfortunately, we didn’t have any ozone measurements at the time, but if there was any increase, it was short-lived. As you can see from the plot below (as accessed here), by the next day there was nothing unusual in the readings. So far this year, all ozone values at Lauder have been remarkably close to the long term mean.

Although we’re currently headed towards the season of lowest ozone amounts, which occur in March, the UVI has passed its summer peak. The peak occurs around the New Year period when ozone amounts are only slightly more, but the noon sun is higher in the sky (so the path-length of radiation passing through the atmosphere is shorter).

I’m not an expert on meteors, but apparently, the next big shower is expected in April. If you want to know more about them, check out this website.