What are these 'alien clouds' and how can you see them?

Noctilucent clouds have an air of mystery around them as it's not fully understood how they form.

Noctilucent clouds: What are those colourful clouds and how can you see them? STV News

Move over northern lights, it’s time for the noctilucent clouds to shine.

Our northerly location means we get to enjoy some of the best displays Mother Naure has to offer when it comes to the aurora, but we also get some of the best views of the beautiful polar noctilucent clouds which create bright highlighted streaks in our summer night skies.

While they don’t dance like the northern lights, they’re equally spectacular to see.

What are noctilucent clouds?

Noctilucent clouds are seen very late or during the early hours.STV News

Noctilucent clouds have an air of mystery around them as it’s not fully understood how they form, but it’s possible we’re seeing them more often in our summers due to climate change.

Noctilucents are not like our usual clouds which live in the lower portion of our atmosphere called the troposphere but are located a whopping 50 miles above us in the mesosphere.

At this very high altitude there is very little moisture available to make clouds, but as the climate warms, a little more is entering these higher elevations from more vigorous storms below.

Like any cloud, the moisture needs a nuclei to cling onto – like a dust or sand particle to condense or to form ice. At these levels the only dust will be from explosive volcanic eruptions or from meteors which have burned up entering our atmosphere – pretty cool stuff.

During summer, polar regions receive continuous sunlight, which paradoxically leads to cooling in the mesosphere. You might think that more sun in the summer should warm the air up, which it does near the ground, but as that air rises it expands and cools.

Bright, smooth, wavy and other-worldly looking - we're seeing more noctilucent clouds than before.STV News

This means in the summer with more warm air rising and cooling it makes the mesosphere colder and perfect for the formation of noctilucent clouds.

This is the climate change connection, as with warmer summers we’ve got more violent convection, which means big punches of air into the upper atmosphere which will cool the mesosphere even more – so while it gets warmer down here, conversely, it’s getting colder up there.

What do these night shining clouds look like?

You’ll see from the photos I took in June 2019 that they have quite a fanciful look to them.

I can only describe them as bright, smooth, wavy and other-worldly looking – you’ll see what I mean when you spot them.

Also, you will only really see them around midnight and during the early hours – outside those times it’ll probably just be cirrus clouds.

The reason they light up our summer skies is because the sun is actually still shining on them as they’re so high up. In our summer the northern hemisphere is tilted toward the sun, so even though the sun is on the other side of the planet in the middle of the night here, the light from it is still peaking over the north pole and hitting these icy wonders high above us.

So, it’s time to start looking out for these alien clouds as they’ll only be with us for a few months while we remain tilted in our summer position. As we move into late August the sun starts to get much lower in the sky and it’s at this point the light will no longer be able to reach the noctilucents at night and they disappear into the shadows for another year.

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