Amazing. Nice. Great.
These are words many people often describe one of the most beautiful specimens in the sky: noctilucent clouds.
And it’s the right time for Canadians to try to see them for themselves, especially during this long weekend, if you have clear skies.
Every year, approximately from early June to August, these clouds, also known as NLC or polar mesospheric clouds, appear in the northern sky.
They are different from the best-known clouds: they appear almost iridescent, bright, and bright as darkness descends, the sun fades, and the stars begin to dot the sky or when darkness begins to turn into daylight. when the sun begins to rise.
Another image of the amazing Noctilucent clouds this morning. Newcastle upon Tyne, United Kingdom. June 23, 2022. pic.twitter.com/FHWJlxnKs8
– @DavidBflower
It seems that the phenomenon has a standard recipe for formation: an increase in water vapor, very cold temperatures and particles, such as excess dust from meteors in our atmosphere or even the escape of rockets, on the which water vapor can be frozen.
The NLCs are also incredibly high in the atmosphere, about 80 miles above sea level. For comparison, the highest clouds we associate with the weather are at altitudes between five and 13 kilometers.
Noctilucent clouds seen over Medicine Hat, Alta., June 26th. (Submitted by Jackie Armstrong)
They are also believed to be a somewhat new phenomenon. They were first reported in 1885, two years after the massive volcanic eruption of Krakatoa. Although the initial belief was that it was due to the eruption and that they would disappear, they have been seen ever since.
How to see them
In the past, NLCs were mostly observed in the high latitudes of the north, making northern Canada an ideal place to observe them. However, in recent years, they have been detected further south, as far as Utah and even Nebraska in the United States.
There is a certain belief that climate change is also contributing to its development and even to being seen in latitudes never seen before. For example, in 2019, they were seen as far south as Joshua Tree, California. The main theory is that with more greenhouse gases in the atmosphere, there is more water vapor available on which they can form.
A 2019 study suggests that the emergence of NLCs fluctuates from year to year and even from decade to decade, but that they have generally become “significantly” more visible.
These bright clouds appear during the summer in the northern hemisphere because more water molecules travel from the lower atmosphere and mix with remnants of meteorites. Also, this is a time when the mesosphere, where these clouds develop, is colder.
MIRAR | Scientists capture a spectacular screen of noctilucent clouds in Canada:
Most of Canada is in a good position to see these undulating clouds, although those in southern Ontario may have more difficulty because they are at a lower latitude.
If you try to spot them, the key is to have a good view of the northern horizon. You really don’t need to get to a dark sky place in this case, as the clouds are bright, lit by the sun below the horizon.
They often appear between 30 minutes and two hours after sunset or between 30 minutes and two hours before sunrise, as the sun should be between five and 13 degrees below the horizon.
And you’ll be able to differentiate them from weather clouds, as those clouds will be dark instead of bright NLC.
So whether you’re at a country house, a park or just celebrating this weekend, remember to look up. You never know what you’ll see.