Light Pillars

Light Pillars
photo © Powhusku
 

Light pillars are beams of light formed by an optical phenomenon created by the reflection of light from flat hexagonal ice crystals horizontally suspended in the atmosphere.

Different shape and colour depend on the source of light, which can be natural (sun, moon) or artificial (streetlights), on the position of the crystals: the higher they are, the taller the pillars are, and on the number and dimensions of the crystals: the larger and more numerous they are, the more pronounced is the effect.
Due to the low temperature required, this effect is typical of arctic regions.

Moonbow

“The rainbow is seen by day, and it was formerly thought that it never appeared by night as a moon rainbow.
This opinion was due to the rarity of the occurrence: it was not observed, for though it does happen it does so rarely.
The reason is that the colours are not so easy to see in the dark and that many other conditions must coincide, and all that in a single day in the month.
For if there is to be one it must be at full moon, and then as the moon is either rising or setting. So we have only met with two instances of a moon rainbow in more than fifty years”

Aristotle – Meteorology, book III  (350 b.C.)
 
 
Moonbows may be seen in waterfalls and cloud forests areas like Yosemite and Cumberland Falls in U.S.A., Victoria Falls in Africa, Plitvice Lakes in Croatia and in the cloud forests of Monteverde and Santa Elena in Costa Rica.
Other places where it is common to see moonbows are the Waimea Canyon State Park (Hawaii), Skogafoss Waterfall, (Iceland),  Wallaman Falls (Australia) and Jerome (U.S.A.).

Borealis & Australis Auroras

Northern lights Alaska
© National Park Service, Alaska Region

The Polar Aurora, well known as Aurora Borealis/Australis or Northern/Southern Lights depending on which hemisphere it occurs, is an optical phenomenon of the atmosphere, characterized by green, blue and red luminous bands with a different range of shapes.

The phenomenon, visible in two stripes around the magnetic poles and more intense and frequent during high solar activity, is caused by the interaction of charged electrons of the solar wind with the earth’s ionosphere (a process similar to the neon lamp light).
The color depends on the atmosphere’s gases: atomic oxygen is responsible for the green, the molecular oxygen for the red and nitrogen for the blue color.

Aurora Borealis
© NASA
According to old myths, the Northern Lights appear for the Inuits like souls playing with walrus skulls, for Lappish they are created by the tail of a big fox that hits the snow and it is believed that children conceived beneath them are more intelligent and lucky.
In Central Europe, they were considered a bad omen due to the predominance of red in its colours.
 
Best places to see Northern Lights / Aurora Borealis (the best period is from September to April):

 


Iceland:
Kirkjufell, Reykjavik, Jökulsárlón Lake, Þingvellir National Park
Norway: Svalbard Islands, North Cape, Tromsø, Alta, Karasjok
Finland: Kakslauttanen Arctic Resort, Inari Lake, Sodanklya, Luosto
Sweden: Abisko National Park, Kiruna region
Alaska, USA: Fairbanks, Denali National Park, Juneau, Barrow, Coldfoot
Canada: Mucho Lake Provincial Park, Yukon, British Columbia, Yellowknife
Greenland: Kulusuk, Ammassalik, Kangerlussuaq
Fær Øer Islands
Russia: Kola Peninsula
Scotland: Caithness coast
Ireland: Donegal region, Malin Head, Antrim region

 
Best places to see Southern Lights / Aurora Australis (the best period is from March to September):

 


Antarctica 

New Zealand: Stewart Island, Lake Tekapo, Aoraki Mt Cook National Park, The Catlins
Australia: Mount Wellington (Tasmania), Victoria
Argentina: Ushuaia
South Georgia Island
Falkland Islands

Waitomo Caves, New Zealand

Waitomo Caves
© 2il org

The Waitomo Glowworm Caves, part of the Waitomo Caves system that includes the Ruakuri Cave and the Aranui Cave, are located in the southern Waikato region of the North Island of New Zealand, about ten km northwest of Te Kuiti.

They are known for its population of thousands Arachnocampa luminosa, a species of glowworms that radiate the ceiling with their blue luminescent, creating a unique atmosphere.

The guided tour brings visitors through the caves by boat rides.

22° Halo (Lunar Halo)

Lunar Halo
photo © mytouristmaps
A 22° halo (known also as moon or solar halo) is an optical phenomenon, forming a circle with a radius of approximately 22° around the moon or sun, produced by reflected/refracted light interacting with millions hexagonal ice crystals suspended in the cirrus or cirrostratus clouds (troposphere, 6-13 km high).


No light is reflected towards the inside of the ring, giving it the impression of a big hole in the sky. As the sailors say, when the 22° halo appears in the sky, a storm is approaching.

In clear sky conditions the view of this phenomenon is spectacular: the one in the photo (taken in Thaba-Tseka, Lesotho) is a lunar halo, much rarer than the solar halo.