In the next few months of summer, one may get to observe golden, silver, and blue streaks across the northern skies in the Northern Hemisphere. These distinct clouds will be visible one to two hours before sunrise and after sunset.
Noctilucent Clouds
This unique phenomenon is referred to as noctilucent clouds, "night-shining clouds," or NLCs, Live Science reports. NLCs are the coldest, rarest, driest, and highest clouds on the planet, based on a 2018 study.
These NLCs pop over the mesosphere, which is a layer of the atmosphere that is situated below the thermosphere and above the stratosphere. It is roughly 47 to 53 miles above the surface of the Earth.
Such NLCs have also been dubbed "space clouds" or "polar mesospheric clouds." They form below the hidden boundary that distinguishes the atmosphere of the Earth and outer space, Live Science notes.
Noctilucent clouds occur when water vapor solidifies into ice crystals that cling to particles and dust that falling meteors leave behind. Scientists have also discovered that the frequency of these NLCs ends up fluctuating each year due to the solar cycle and atmospheric changes, Space.com reports.
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How To Spot Noctilucent Clouds
Space.com notes that these high-altitude clouds can only be viewed under very specific conditions and that they appear during the summer. During this time, the mesosphere is at its coldest point at the poles.
Live Science adds that the peak time to observe NLCs across the northern hemisphere is around the time the summer solstice takes place in late June up until the end of July.
These NLC sightings have become more prevalent in the past few years, especially in lower latitudes. NOAA notes that this could be due to how climate change leads to more water vapor generation due to the increased levels of methane in the atmosphere. In fact, last summer, sightings of NLCs reached a 15-year record high, the Washington Post notes.
As per Windy, they are most visible from roughly 50 to 70 degrees north latitude. However, according to Spaceweather.com, some of them were already sighted in northern and colder regions, such as Denmark.
To get the best possible view of NLCs during the night, one may need to find a good viewing spot that is low in the northern horizon as the stars start shining. Sky & Telescope notes that displays can be typically seen at roughly 20 to 25 degrees in the northern sky.
It is best to catch a glimpse of these night-shining clouds with the naked eye. However, using premium stargazing binoculars may enable one to get an impressive close-up view of the stunning sky sight.
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