Astronomy/Hallo around Sun

Advertisement

Expert: - 5/27/2008


Question
Hi Philip,

I live in Central CA and today at 2:00 pm the Sun has a colorful halo around
it.

It looks like  a rainbow around the Sun. AMAZING!'
What would cause that?

LEANA

Answer
Hello,

How large would you say the angular dimension (radius) of the halo was? About 20-22 degrees? (Bearing in mind the Sun is a half degree across). If so, then it was likely caused by ice crystals in the atmosphere refracting incident sunlight.

A previous question (and my answer) also addressed this for the case of the Moon. The same agency applies to halos of the stated dimension formed around the Sun.

Astronomy

All Answers

Answers by Expert:

Ask Experts

Volunteer

Philip Stahl

Expertise

I have forty years of experience in Astronomy, specifically solar and space physics. My specialties include the physics of solar flares, sunspots, including their effects on Earth and statistics as applied to astronomical investigations.

Experience

Astronomy: more than forty years experience starting with construction of my own simple telescopes. Worked at university observatory in college, doing astrographic measurements. M.Phil. degree in Physics/Solar Physics and more than ten years as researcher.

Organizations
American Astronomical Society (Solar Physics and Dynamical Astronomy divisions), American Mathematical Society, American Geophysical Union

Publications
Solar Physics (journal), The Journal of the Royal Astronomical Society of Canada, The Proceedings of the Meudon Solar Flare Workshop (1986), The Proceedings of the Caribbean Physics Conference (1985). Books: 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level'.

Education/Credentials
B.A. Astronomy, M. Phil. Physics

Awards and Honors
American Astronomical Society Studentship Award (1984), Barbados Government Award for Solar Research

©2012 About.com, a part of The New York Times Company. All rights reserved.