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Astronomy Picture of the Day 12-30-02
NASA ^
| 12-30-02
| Robert Nemiroff and Jerry Bonnell
Posted on 12/30/2002 12:21:46 AM PST by petuniasevan
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2002 December 30

A Sun Pillar
Credit & Copyright: Dave Liquorice
Explanation: Have you ever seen a sun pillar? When the air is cold and the Sun is rising or setting, falling ice crystals can reflect sunlight and create an unusual column of light. Ice sometimes forms flat, stop-sign shaped crystals as it falls from high-level clouds. Air resistance causes these crystals to lie nearly flat much of the time as they flutter to the ground. Sunlight reflects off crystals that are properly aligned, creating the sun-pillar effect. In the above picture, a sun-pillar reflects light from a setting Sun.
TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: air; atmospheric; clouds; crystals; fog; halo; ice; light; parhelia; phenomena; pillar; sky; sun; sundogs
The effects depend on the shape and orientation of the ice crystals. Halos can be found around other bright objects, such as the Moon or streetlights.
More APOD halos for your enjoyment:






To: MozartLover; Joan912; NovemberCharlie; snowfox; Dawgsquat; viligantcitizen; theDentist; ...
To: petuniasevan
Ah! I see now how the symbol for the Sun possibly came about. (A dot surrounded by a disk)
3
posted on
12/30/2002 1:47:45 AM PST
by
BradyLS
To: BradyLS
Quite possible.
To: petuniasevan
These are great....thanks for the ping (-:
5
posted on
12/30/2002 4:23:10 AM PST
by
firewalk
To: petuniasevan
Wow ! Beautiful. Mother Nature sure does a GREAT job, huh?...
To: petuniasevan
Wow! What a series of pictures to come back to! Thanks.
To: petuniasevan
Beautiful!
Thanks for the ping.
To: petuniasevan
Those are fine examples of the phenomena. The sun dogs in the top image show only part of the full display.
There is a white spot with no color in the sky at the opposite position of the sun at the same altitude and a showshoe shaped figure tangent to the ring at the top above the sun that crosses over the top of the sky and ends up at the white spot.
The white ring horizontal to the ground goes all the way around the sky and meets the white spot opposite the sun.
Note the prismatic colors at the bright spots and note also that the interior of the ring is darker than the rest of the sky. The light for the display comes from the inside of the ring.
To: petuniasevan
Beautiful pictures!
To: petuniasevan
AWSOME! Great pictures. We have seen many of these types of pillars here in Duchesne Utah. Tonight how ever its to darn foggy to see much of anything. Great work on this site!
To: petuniasevan
12
posted on
03/03/2025 7:42:41 AM PST
by
No name given
( Anonymous is who you’ll know me as)
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