The Horsehead Nebula, is one of the most recognizable sites in the cosmos. It lies in the Orion constellation, about 1,500 light years away. Just to put into proportion how massive this structure is, its head alone is about five light years tall.
Normally, when we think of nebulae, we think of glowing clouds of gas in space. However, not all nebulae are luminous.
The Horsehead is what is referred to as adark nebula. Quick factoid, all nebulae are made of ionized, mostly hydrogen, gas. Many of them either reflect or emit light, but not all. In cases of dark nebulae, a thick cloud of gas obstructs the light coming from a source in the background. Essentially, they are silhouettes.
Recent pictures have been taken, with the help of the Hubble telescope, that shed, literally, new light on the Horsehead nebula! Using a different filter that detect only the wavelengths of infrared light, we can get a better look at the cloud of dust that comprises this popular astronomical sight.
In, what is in my opinion, one of the most spectacular photographs ever taken, we can see the billowing creases and folds of the dust cloud that, until now, has alluded our detection. Viewing this section of sky in infrared we make out the details of the cloud’s shape never before seen.
Zooming in we can get a close up look at what actually makes up the head. It doesn’t look so much like a horse anymore, does it? In fact, it is more beautiful than I ever could have imagined.
“This image, the first to be released publicly from VISTA, the world’s largest survey telescope… the ghostly outline of the Horsehead Nebula [is visible ]. The bright bluish star towards the right is one of the three bright stars forming the Belt of Orion. The image was created from VISTA images taken through [three different] filters in the near-infrared part of the spectrum… The total exposure time was 14 minutes” (VISTA).
Filters allow us to see images that are not visible to our eyes naturally. The electromagnetic spectrum of light radiation is quite vast. It stretches from the longest of radio waves to the shortest, most energy packed gamma rays, with the portion of visible light sandwiched roughly, in the middle. By using telescopes that can pick up on specific wavelengths of light it makes it possible to study the region of sky in a detail unknown to us before. So, cheers to the Horshead in infrared!
- Vista/ESO (Visible and Infrared Survey Telescope for Astronomy and the Hubble space Telescope)