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.
Explanation:
What if you woke up one morning and saw
more than one Sun in the sky?
Most probably, you would be seeing sundogs, extra-images of the
Sun created by falling
ice-crystals in the Earth's atmosphere.
As water freezes in the atmosphere,
small, flat, six-sided,
ice crystals might be formed.
As these crystals flutter to the ground,
much time is spent with their faces flat, parallel to the ground.
An observer may pass through the same plane as many of the
falling ice crystals near sunrise or sunset.
During this alignment, each crystal can act like a miniature lens,
refracting sunlight into our view and creating
parhelia,
the technical term for sundogs.
Sundogs were
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell (USRA)
<
Archive
| Index
| Search
| Calendar
| Glossary
| Education
| About APOD
>
NASA Technical Rep.:
Jay Norris.
Specific rights apply.
A service of:
LHEA at
NASA/
GSFC
&
Michigan Tech. U.