Comments and questions about the APOD
on the main view screen.
- Otto Posterman
- Posts: 4525
- Joined: Fri Dec 04, 2009 3:27 am
The Horsehead Nebula
One of the most identifiable nebulae in the sky, the Horsehead Nebula
, is part of a large, dark, molecular cloud
. Also known as Barnard
33, the unusual shape was first discovered
on a photographic plate
in the late 1800s. The red glow originates from hydrogen
gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis
. The darkness of the Horsehead
is caused mostly by thick dust
, although the lower part of the Horsehead
's neck casts a shadow to the left. Streams of gas leaving the nebula
are funneled by a strong magnetic field
. Bright spots in the Horsehead Nebula
's base are young stars just in the process of forming
. Light takes about 1,500 years to reach us from the Horsehead Nebula
. The featured image
was taken with the large 3.6-m Canada-France-Hawaii Telescope
- :---[===] *
- Posts: 2691
- Joined: Sun Apr 22, 2007 12:07 am
WOW... that has got to be the most DETAILED image of it, I have seen... differentiation between sections, with some depth...layers of dark grey, and strands... just WOW...
- Posts: 1398
- Joined: Mon Aug 29, 2005 12:46 am
- Location: Auburn, Washington, USA
have to get the bazillion pixel poster and an ice col one, like pairing up Star War mo vie an 3D glasses.
- 4725 Å
- Posts: 11712
- Joined: Sat May 29, 2010 5:33 am
I'd like to add a few words about Sigma Orionis, whose ultraviolet light ionizes the red background nebula and sculpts the shape of the Horsehead itself.
Sigma Orionis is a multiple star somewhat comparable to the Trapezium Cluster
, even though the most massive member of Sigma Orionis is not comparable to Theta 1C Orionis
in the Trapezium. The brightest component of Sigma Orionis, Sigma Orionis Aa, is a hot blue star of spectral class O9.5V, which radiates 35,000 times as much energy as the Sun from a 32,000K surface.
Read more here
- Science Officer
- Posts: 430
- Joined: Mon Sep 30, 2013 6:35 pm
Know what? With this new close up of the Horsehead Nebula, with the shape of the snout, it looks more like a moose head than a horse. Should we start a petition to rename it the Bullwinklehead Nebula?
I SEE THE GRINCH!!! In red, on the back of the horses head... Maybe a little too much egg nog this weekend... Sorry if I alarmed anyone...
- Vacationer at Tralfamadore
- Posts: 18725
- Joined: Mon Jan 21, 2008 1:57 pm
- Location: Alexandria, Virginia
The Stars, Like Dust
(1951) by Isaac Asimov: Asimov conducts a clinic on geocentrism in a galactic setting, having a character state that the literal adjective "horsehead" is meaningless from non-terrestrial vantages, and that the "generally believed" alternate derivation (that the nebula was first breached by the eponymous explorer Horace Hedd) is far more plausible.
The Hitchhiker's Guide to the Galaxy
(1979) by Douglas Adams: Galactic President Zaphod Beeblebrox and his companion Trillian have stolen the Infinite Improbability Drive prototype ship Heart of Gold. Reaching the Horsehead Nebula, and recognizing their location by the sheer impenetrable darkness outside, they discover the ancient planet Magrathea and its twin suns Soulianis and Rahm. Magrathea is a world whose economy was based on the manufacturing of bespoke planets for the wealthiest people in the universe, back in the days of the Galactic Empire (it was Magrathea that created the Earth).