Image Credit & Copyright: John Chumack
Explanation: The Horsehead Nebula is one
of the most famous nebulae on the sky. It is visible as the dark
indentation to the red emission nebula in
the center of the above photograph. The horse-head
feature is dark because it is really an opaque dust
cloud that lies in front of the bright red emission
nebula. Like clouds in Earth's
atmosphere, this cosmic cloud has assumed a recognizable shape by
chance. After many thousands of years, the internal motions of the cloud will
alter its appearance. The emission nebula's red
color is caused by electrons
recombining with protons
to form hydrogen atoms. Also
visible at the bottom left of the picture is a greenish reflection nebulae that preferentially reflects the blue light from
nearby stars.
Aucun commentaire:
Enregistrer un commentaire