ST. PETERSBURG, Fla. — Did you walk outside this morning and see a strange cloud illuminate the sky and wonder what the heck it was?
You're not alone. And, the answer's both relatively simple and really cool.
So what was it? It's called a noctilucent cloud, or a "night-shining" mesospheric cloud, according to the National Weather Service. Also called a "space jellyfish." More on that later.
Basically, these types of clouds form at much higher altitudes — about 50 miles above Earth — than typical clouds, which generally only reach heights of up to 10 miles above Earth.
Because they're so high up, the atmosphere is really cold at that altitude, with temperatures reaching -180 degrees Fahrenheit. So, the water vapor forming the clouds actually turns into ice crystals.
Those ice crystal clouds then catch the light of the sun that's still below the horizon and in turn appear bright in the pre-dawn sky.
The National Oceanic and Atmospheric Administration's National Centers for Environmental Information says the first recorded observations of noctilucent clouds (NLCs) happened after 1885. "NLCs are considered harbingers of climate change resulting from the presence of increased atmospheric methane."
Why did it happen? SpaceX launched its latest batch of Starlink satellites into space around 5:42 a.m. from Cape Canaveral.
So the clouds were formed in part from the rocket's exhaust plume. The noctilucent clouds formed during a launch are also called "space jellyfish," according to Florida Today.
10 Tampa Bay Meteorologist Grant Gilmore says as the exhaust plume expands in the lighter part of the atmosphere, the sunlight is reflected off the moisture and ice crystals left over from the plume.