Archive for noctilucent clouds

Arctic Circle have reported nightly displays of bright noctilucent clouds.

Posted in 2017, astronomy, Galaxy with tags , , on July 29, 2017 by theboldcorsicanflame


NASA’s AIM spacecraft took this picture of the entire Arctic surrounded by an electric-blue glow on July 24th

NOCTILUCENT CLOUDS FROM SPACE: This week, sky watchers near the Arctic Circle have reported nightly displays of bright noctilucent clouds.  The silvery ripples of NLCs look amazing from the ground, but they look even better from space. 

Regular readers of have been waiting for this image since June. Normally, AIM  transmits pictures of NLCs every day, but the regular flow of data was interrupted months ago. The reason has to do with the spacecraft’s orbit. Since AIM was launched in 2007, its orbit has been precessing–that is, slowly rotating with respect to the planet below. Eventually, accumulated changes in AIM’s orbital elements required a new way of pointing the spacecraft’s instruments. Mission controllers have been working on that problem all summer long–and it has finally been solved.



August is the month when noctilucent clouds (NLCs) typically begin to wane

Posted in 2016, astronomy with tags , , , on August 9, 2016 by theboldcorsicanflame



August is the month when noctilucent clouds (NLCs) typically begin to wane.

Indeed, images from NASA’s AIM spacecraft show the electric-blue oval around the north pole is beginning to recede.

Nevertheless, high-latitude sky watchers are still seeing some impressive displays.



Climate Change at the Edge of Space

Posted in 2016, astronomy with tags , , , on June 30, 2016 by theboldcorsicanflame


Noctilucent clouds overNykøbing Mors, Denmark, on June 13, 2016. Photo credit: Ruslan Merzlyakov

“noctilucent clouds” (NLCs). They appear with regularity in summer months, shining against the starry sky at the edge of twilight. Back in the 19th century you had to go to Arctic latitudes to see them.

In recent years, however, they have been sighted from backyards as far south as Colorado and Kansas.

Noctilucent clouds are such a mystery that in 2007 NASA launched a spacecraft to study them.

The Aeronomy of Ice in the Mesosphere satellite (AIM) is equipped with sensors specifically designed to study the swarms of ice crystals that make up NLCs.  Researchers call these swarms “polar mesospheric clouds” (PMCs).

Read all about it on

Climate Change at the Edge of Space






Posted in 2014, astronomy with tags , , , on July 8, 2014 by theboldcorsicanflame


Forecasters expected a solar flare today, and indeed one has occurred. But it came from an unexpected source. Emerging sunspot AR2113 showed that it is capable of strong flares with an M6-class eruption at 1630 UT on July 8th. NASA’s Solar Dynamics Observatory recorded the extreme ultraviolet flash

Ionizing radiation from the flare briefly disturbed the propagation of shortwave radio transmissions on the dayside of Earth, but conditions have since returned to normal. The impulsive flare might have produced a coronal mass ejection (CME); if so, the storm cloud is almost certainly not heading toward Earth. For now, this sunspot is too far off the sun-Earth line to produce geoeffective CMEs.

With this flare, AR2113 joins two other sunspots capable of potent activity: AR2108 and AR2109. NOAA forecasters estimate a 70% chance of M-flares and a 15% chance of X-flares on July 8th. Solar flare alerts: textvoice

This morning in Russia, the sunrise was electric-blue. Bright bands of noctilucent clouds zig-zagged like lightning across the twilight sky, continuing a two-day display that has delighted observers across northern Europe. Michael Zavyalov sends this picture taken July 8th from the city of Yaroslavl:

“Another night with bright noctilucent clouds (NLCs) in Yaroslavl!” says Zavyalov. “We could even see their reflection in the water.”

NLCs are Earth’s highest clouds. Seeded by “meteor smoke,” they form at the edge of space 83 km above Earth’s surface. When sunlight hits the tiny ice crystals that make up these clouds, they glow electric blue. 

In the northern hemisphere, July is the best month to see them. NLCs appear during summer because that is when water molecules are wafted up from the lower atmosphere to mix with the meteor smoke. That is also, ironically, when the upper atmosphere is coldest, allowing the ice crystals of NLCs to form.

The natural habitat of noctilucent clouds is the Arctic Circle. In recent years, however, they have spread to lower latitudes with sightings as far south as Utah and Colorado. This will likely happen in 2014 as well. Observing tips: Look west 30 to 60 minutes after sunset when the Sun has dipped 6o to 16o below the horizon. If you see blue-white tendrils zig-zagging across the sky, you may have spotted a noctilucent cloud.

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