Orion's got cavities!

Bad Astronomy
The entire universe in blog form
Oct. 26 2011 7:00 AM

Orion's got cavities!

The Orion Nebula is perhaps the most famous gas cloud in the sky. And no wonder: it's easily visible to the unaided eye, it looks fuzzy and diffuse even in binoculars, in small telescopes its shape can be discerned, and in long time exposures its beauty is devastating. The delicate wisps and tendrils, the bold colors, the odd shape... it's got it all.

I've seen hundreds of pictures of it, and there's almost always something new to see. But I don't think I've ever seen a shot of it quite like this:

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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Isn't that incredible? It was taken by Jesus Vargas (Astrogades) and Maritxu Poyal [click to ennebulenate]. Amazingly, it was taken with a telescope that had a lens only 10.6 cm (4") across! But the nebula is so bright that it doesn't take a big 'scope to get great images of it (though, to be fair, Takahashi makes very high quality 'scopes).

What I like about this image is how obviously it shows that the nebula is actually a giant cavity in space. The actual cloud is far larger than what you see here, very dense and dark. But many stars are forming in the heart of the Orion Nebula, and a handful of them are massive and hot. Their ultraviolet radiation has flooded the interior of the cloud, eating away at it, carving out a huge divot light years across, and lighting it up. What you're seeing here is more tenuous gas filling that cavity.

I love that. When I was younger I thought the nebula was just this diffuse puffery floating out in space, but reality is -- as usual -- more interesting, more profound, and more awesome than what we might first think. Images like this really drive that home.

Vargas and Poyal have several other images of this magnificent gas cloud, including this slightly wider field-of-view, one with different color filters, and one with a much wider field-of-View. These are all magnificent, and well worth your time looking at.

I've written about this nebula many times, as you might expect. Check out the Related posts links below for lots more info on this fantastic object.

Image credit: Jesus Vargas and Maritxu Poyal, used by permission.



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