Orion Molecular Cloud Complex, dominated in the center of this view by the brilliant Flame nebula (NGC 2024). The smaller, glowing cavity falling between the Flame nebula and the Horsehead is called NGC 2023. Image credit: NASA/JPL-Caltech.
Noctilucent clouds were once thought to be a fairly modern phenomenon. A team of researcher have recently calculated that Earth and the entire Solar System may well have passed through two dense interstellar clouds causing global noctilucent clouds that may have driven an ice age. The event is thought to have happened 7 million years ago and would have compressed the heliosphere, exposing Earth to the interstellar medium.
Noctilucent clouds, or PMC's, form high in the atmosphere above the poles. NASA launched a five-day balloon mission to observe and photograph them. Image: NASA’s Goddard Space Flight Center/Joy Ng
Noctilucent clouds are one of the atmosphere’s most ethereal natural wonders. They form high in the mesosphere, about 80 km (50 mi) above the Earth’s surface, and are rarely seen. In July, 2018, NASA launched a five-day balloon mission, called PMC (Polar Mesospheric Clouds) Turbo, to observe them and photograph them.
Noctilucent clouds over the city of Rosmalen, Holland, July 3, 2014. Taken with Canon 60D, 28 mm lens. Credit: Rob van Mackelenbergh
A trio of talented Dutch astrophotographers have captured a series of magnificent views of the rare and beautiful phenomena known as Noctilucent Clouds, or NLCs, during a spectacular outburst on the night of July 3, 2014 in the dark skies over southern Holland – coincidentally coinciding with the fireworks displays of the Dutch 2014 FIFA World Cup team and America’s 4th of July Independence Day celebrations!
“I suddenly saw them above my city on the night of July 3rd and ran for my camera!” said Dutch astrophotographer Rob van Mackelenbergh, who lives in the city of Rosmalen and excitedly emailed me his photos – see above and below.
“I was lucky to see them because I left work early.”
Noctilucent clouds are rather mysterious and often described as “alien looking” with “electric-blue ripples and pale tendrils reaching across the night sky resembling something from another world,” according to a NASA description.
Noctilucent clouds over the city of Rosmalen, Holland, July 3, 2014. Taken with Canon 60D, 28 mm lens. Credit: Rob van Mackelenbergh
They are Earth’s highest clouds, forming on tiny crystals of water ice and dust particles high in the mesosphere near the edge of space by a process known as nucleation, at altitudes of about 76 to 85 kilometers (47 to 53 miles).
NLCs are generally only visible on rare occasions in the late spring to summer months in the hours after sunset and at high latitudes – 50° to 70° north and south of the equator.
Noctilucent clouds over the city of Rosmalen, Holland, July 3, 2014. Taken with Canon 60D, 28 mm lens. Credit: Rob van Mackelenbergh
Another pair of Dutch guys, Raymond Westheim and Edwin van Schijndel, quickly hit the road to find a clear view when they likewise saw the mesmerizingly colorful and richly hued outburst on July 3rd and also sent me their fabulous NLC photos.
“To have a free view to the horizon, we drove to the countryside just north of the city of Oss. On a small road we have stopped to witness these beautiful NLCs and to take pictures,” said Westheim.
Late night Noctilucent clouds outside Oss, Holland, July 3, 2014. Taken with Canon EOS 450D, 17-40 mm lens, ISO 200, f=5.6, exposure time 5-15 seconds. Credit: Raymond Westheim
See a gallery of Raymond’s and Edwin’s photos herein.
“The NLCs of last night were the most beautiful ones since 2010. They were remarkably bright and rapidly changing and could be seen drifting towards the South,” Westheim explained with glee.
“These pictures were taken a few kilometers north of our city Oss between 23:15 p.m. and 0:15 a.m. (Central Europe Time) on Thursday evening, July 3,” said Edwin van Schijndel.
Noctilucent clouds near Oss, Holland on July 3, 2014. Taken with Canon EOS 60 D, 17 – 40 Canon lens, exposure time 2 to 4 seconds, ISO 200. Credit: Edwin van Schijndel
Rob, Raymond and Edwin are all members of the “Sterrenwacht Halley” Observatory which was built in 1987. It houses a planetarium and a Celestron C14 Schmidt-Cassegrain telescope. The observatory is located about 50 kilometers from the border with Belgium, near Den Bosch – the capitol city of southern Holland. The well known club hosts astronomy lectures and star parties to educate the public about astronomy and science.
The spectacular NLC sky show is apparently visible across Europe. Spaceweather.com has received NLC reports “from France, Germany, Poland, the Netherlands, Scotland, Ireland, England, Estonia and Belgium.”
Here are some additional NLC Observing Tips from NASA:
NLC Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6 degrees to 16 degrees below the horizon. If you see luminous blue-white tendrils spreading across the sky, you’ve probably spotted a noctilucent cloud. Although noctilucent clouds appear most often at arctic latitudes, they have been sighted in recent years as far south as Colorado, Utah and Nebraska. NLCs are seasonal, appearing most often in late spring and summer. In the northern hemisphere, the best time to look would be between mid-May and the end of August.
The first reported sighting of NLC’s are relatively recent in 1885 by a German astronomer named T.W. Backhouse, some two years after the enormous eruption of the Krakatoa Volcano in 1883 that wreaked enormous death and destruction and which may or may not be related.
Over the past few years, astronaut crews aboard the ISS have also photographed splendid NLC imagery from low Earth orbit.
Stay tuned here for Ken’s continuing OCO-2, GPM, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, MAVEN, MOM, Mars and more Earth & Planetary science and human spaceflight news.
Late night Noctilucent clouds outside Oss, Holland, July 3, 2014. Taken with Canon EOS 450D, 17-40 mm lens, ISO 200, f=5.6, exposure time 5-15 seconds. Credit: Raymond Westheim
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Learn more about NASA’s Mars missions and Orbital Sciences Antares ISS launch on July 11 from NASA Wallops, VA in July and more about SpaceX, Boeing and commercial space and more at Ken’s upcoming presentations.
July 10/11: “Antares/Cygnus ISS Launch from Virginia” & “Space mission updates”; Rodeway Inn, Chincoteague, VA, evening
Late night Noctilucent clouds outside Oss, Holland, July 3, 2014. Taken with Canon EOS 450D, 17-40 mm lens, ISO 200, f=5.6, exposure time 5-15 seconds. Credit: Raymond Westheim
Late night Noctilucent clouds outside Oss, Holland, July 3, 2014. Taken with Canon EOS 450D, 17-40 mm lens, ISO 200, f=5.6, exposure time 5-15 seconds. Credit: Raymond Westheim
Noctilucent clouds near Oss, Holland on July 3, 2014. Taken with Canon EOS 60 D, 17 – 40 Canon lens, exposure time 2 to 4 seconds, ISO 200. Credit: Edwin van Schijndel
Sterrenwacht Halley Observatory in Holland. Credit: Rob van Mackelenbergh
Soon you may see an eerie spectacle on clear summer nights if you are located at latitudes between 50° and 70° north and south of the equator: Noctilucent Clouds.
These ghostly apparitions are a delight to see and are quite rare. It is incredibly difficult to predict exactly when they will appear, but we do know they should begin to appear soon.
The season for Noctilucent Clouds (Noctilucent = Latin for “Night Shining”) starts early June and continues into late July. They are seen just after dusk, or before dawn and an apparition can last around an hour.
These mysterious clouds, with their bizarre tenuous wispy shapes reminiscent of ripples in sand or the changing surface of a pool of water, spread like a glowing web across the northern sky. Colours can range from brilliant whites, with tinges of blue, pink and orange.
Formed by tiny ice crystals, they are the highest clouds in the Earth’s atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 miles) almost at the edge of space.
They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon, while the lower layers of the atmosphere are in the Earth’s shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon, only being recorded for about 120 years.
Noctilucent clouds can only form under very restrictive conditions, and their occurrence can be used as a guide to changes in the upper atmosphere. Since their relatively recent classification, the occurrence of noctilucent clouds appears to be increasing in frequency, brightness and extent.
There is evidence that the relatively recent appearance of noctilucent clouds and their gradual increase, may be linked to climate change. Another recent theory is that some of these bright displays come from particulates and water vapour in the atmosphere left over from Space Shuttle launches.
How can you see them? Over the next couple of months look north during dusk and dawn and try and spot this mysterious and elusive phenomenon. They are best seen when the sun is between 6 and 16 degrees below the horizon, and seem to occur more frequently in the Northern hemisphere than the Southern.
Good luck!
Noctilucent clouds over Blair, Nebraska, USA. Credit: Mike Hollingshead
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Seen from space, the Earth’s atmosphere is incredibly thin, like a slight haze around the planet. But the atmosphere has several different layers that scientists have identified; from the thick atmosphere that we breathe to the tenuous exosphere that extends out thousands of kilometers from the Earth. Let’s take a look at the different atmosphere layers.
Scientists have identified 5 distinct layers of the atmosphere, starting with the thickest near the surface, and then thinning out until it eventually merges with space.
The troposphere is the first layer above the surface of the Earth, and it contains 75% of the Earth’s atmosphere, and 99% of its water. Breathe in, that’s the troposphere. The average depth of the troposphere is about 17 km high. It gets deeper in the tropical regions, up to 20 km, and then shallower near the Earth’s poles – down to 7 km thick. Temperature and pressure are at the their highest at sea level, and then decrease with altitude. The troposphere is also where we experience weather.
The next atmosphere layer is the stratosphere, extending above the troposphere to an altitude of 51 km. Unlike the troposphere, temperature actually increases with height. Commercial airlines will typically fly in the stratosphere because it’s very stable; above weather, and allows them to optimize burning jet fuel. You might be surprised to know that bacterial life survives in the stratosphere.
Above that is the mesosphere, which starts at about 50-85 km above the Earth’s surface and extends up to an altitude of 80-90 km. Temperatures decrease the higher you go in the mesosphere, reaching a low of -100 °C, depending on the latitude and season.
Next comes the thermosphere. This region starts around 90 km above the Earth and goes up to about 320 and 380 km. The International Space Station orbits within the thermosphere. This is the region of the atmosphere where ultraviolet radiation causes ionization, and we can see auroras. Temperatures in the thermosphere can actually reach 2,500 °C; however, it wouldn’t feel warm because the atmosphere is so thin.
The 5th and final layer of the Earth’s atmosphere is the exosphere. This starts above the thermosphere and extends out for hundreds and even thousands of kilometers. Air molecules in this region can travel for hundreds of kilometers without bouncing into another particle.
