Physics Photo of the Week
March
11,
2011
Orion Nebula
Description by Evelyn Breziner
and Ryan Fougnier
The Orion Nebula is a diffuse nebula situated south of Orion’s Belt. It
is one of the brightest nebulas in the sky, and can be observed in the
night-sky in plain sight from Earth. Orion’s Nebula is one of the most
photographed, examined, and investigated astronomical bodies—from it,
astronomers have obtained information that has determined the formation
of stars and planets from clouds made of powder and gas. Stars
are currently forming in this cloud of gas and dust. Ever since
the Hubble Space Telescope first observed the nebula in 1993, it has
been an important subject of research for astronomers trying to
understand how star/planet systems, like our Solar System, are formed.
This photo of the Orion Nebula was taken on the evening of March 1st by
a small group from Dr. Collins’ Earth, Light, and Sky class: Kate Collins, Elan Gabel-Richards,
Gabriel Sistare, Rashad Ali, James Halal, and Ryan Fougnier. By
means of a telescope, CCD camera, and computer, this image is actually
a sum
of dozens of images taken over the course of a two hour observation
session. The Orion Nebula, also called M42, is located 1,344
lightyears from Earth in the constellation Orion. Although its
discovery and understanding can be credited to many astronomers over
the past few hundred years, it was Charles Messier who first catalogued
the nebula in detail in 1796, hence the name Messier 42, or M42.
The Nebula has three greenish zones, in addition to some red and bluish
regions with violet tints. The red tonality can be explained by the
emission of hydrogen radiation. The hydrogen atoms in the cloud absorb
the high energy light from ultra violet radiation from the Spectral O
stars deep in the center of the nebula. Upon absorption of the
ultraviolet radiation, the hydrogen gas emits the characteristic red
light. The blue-violet color is the dust in the nebula reflecting
visible blue light from these same very hot Spectral O-type
stars. The cause of the green color has been a subject of much
debate early in the 20th century, as astronomers had a difficult time
pinpointing its exact causes. With technological advances, it was
concluded that the green color was caused by the transition of an
electron over an oxygen atom. This type of radiation, however, is
impossible to reproduce in laboratories. It depends upon a medium
in which the excited oxygen atoms don't collide with any other atoms -
characteristics that can only exist in outer space.
There will be no Physics Photo of the Week next week due to spring
break at Warren Wilson College. The next Physics Photo of the
Week will be published on March 25, 2011.
Physics
Photo of the
Week is
published weekly during the academic year on Fridays by the Warren
Wilson College Physics
Department. These photos feature interesting phenomena in
the world around us. Students, faculty, and others are invited to
submit digital (or film) photographs for publication and
explanation. Atmospheric phenomena are especially welcome.
Please send any photos to dcollins@warren-wilson.edu.
All photos and discussions are copyright by Donald
Collins or by the person credited for the photo and/or
discussion. These photos and discussions may be used for private
individual use or educational use. Any commercial use without
written permission of the photoprovider is forbidden.
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